Science Matters with Rod Charlton

A New Turn Of Events

2009-06-29T17:34:00.000-07:00

Hello Readers... my science column was carried in the Brockville Recorder and Times, but they have come under severe cost restraints and have had to eliminate frills such as science columns. This leaves me free to use this blog for my columns, although without financial reward.
I admit to not being as diligent as I could in keeping this blog up-to-date, but now that I am not constrained by either a bi-weekly schedule or a specific length limit, I may be able to be more flexible.
I welcome your comments about the content, the tone or any other part of my blog.
Thank you for reading and please let me know what you think.

Solar Energy - Solar Heating

2009-06-29T17:31:00.000-07:00

SOLAR ENERGY 2 – SOLAR HEATING

In my last column we looked at photovoltaics, the generation of electricity using sunlight. This week we will look at solar heating, SH.

SH is something we are all familiar with… remember those black vinyl car seats on a summer day when we were kids… ouch! Let’s see what can be done with this energy.

Solar heaters are available today in several forms, and a reasonably efficient version can be made with readily available materials. If you want to heat your swimming pool, simply putting a coil of black pipe on the south-facing garage roof, connected to the recirculating line will make a difference to your pool, and you can upgrade to more efficient designs fairly easily. In many tropical and sub-tropical countries, rooftop solar heaters are commonly used to supply domestic hot water, with small electric or fuel-fired in-line heaters to make up for cloudy days or night-time use. Passive solar heating consists of laying a floor of stone or tile in a south-facing room and allowing the low winter sun to warm it. Because stone and tile absorb heat slowly and release it slowly, this design can make a small difference to heating a room, even in Canadian winters.

More sophisticated systems can be fitted to homes to supply the bulk of the heating needs, even in Canada. These consist of a non-freezing fluid that is pumped through a flat panel collector on your roof and then through tubing incorporated into the floor, for example. The angle of the panel is critical to obtain efficient use of the sunlight, which is why you may see these mounted at awkward-looking angles. These systems require back-up power, but clearly would reduce the need for conventionally-generated power.

The large-scale generation of electricity through SH is also well advanced. In Spain a system has been in operation for several years. It involves a roughly circular field of flat mirrors, which move to track the sun and reflect the sunlight to a central tower. Inside the tower is a receiver in which a fluid (water) is heated to over 500 deg. C. and the resultant steam turns a turbine to generate 11 MW of electricity. This is over double the output of the photovoltaic plant in Arizona we looked at in the last column. As with photovoltaics, there are no emissions associated with this, but also it takes some land area, and more maintenance is required. Not everyone wants a 300 ft. tower in their neighbourhood.

The latest designs involve parabolic reflector technology. A parabola is a curve, a bit like the narrow end of an egg, which has the very useful property of focussing all the incident light onto one spot. So a parabolic reflector, in the form of a trough with a pipe containing water or glycol solution (similar to the fluid in your car radiator) running along inside it is a very effective way to capture solar heat. The catch (there is always a catch) is that the reflector has to track to sun to maximise efficiency. The good part is that you don’t need a tower, but you pipe the heated fluid directly to a generator building. Again, there are no emissions but maintenance is required for pumps, generators, and tracking mechanisms, as well as ensuring that the mirrors are kept clean. As with PV systems, there is a need for some form of storage so that energy can be generated at night and in cloudy weather. With SH systems, the latest technology involves heating a salt solution and storing it in a tank. The stored heat can be used to generate steam to run turbines and generators at night.

The world has about 500 MW of installed capacity, about 100 MW of planned capacity and about 2700 MW of announced intent to build capacity. This is a small but significant portion of our needs. All of this is in tropical or sub-tropical locations, and the newest plants use the parabolic trough technology, with computer-controlled tracking to obtain the highest efficiency. Efficiencies of about 40% have been claimed, compared with 15% for PV systems, based on the conversion of sunlight to electricity.

Currently the largest operational system is in California’s Mojave desert, with 354 MW capacity. This could supply over 300,000 homes. Even at this scale, the cost of SEGS electricity (solar energy generating system) is three to five times the cost of conventionally generated electricity. However, as we are painfully aware, the cost of fuel (natural gas and oil) is certainly not going down, so the gap is likely to narrow quickly.

So you can see that both photovoltaics and solar heating can play a significant part in meeting our energy needs, even with their known drawbacks. Their key advantage, that of generating power without accompanying greenhouse gas emissions, can only help in ensuring their widening adoption in the coming years. As well, if governments, utilities, and regulators are serious about reducing greenhouse gas emissions, they will have to encourage this kind of development through tax incentives, price supports and other inducements. Only through these actions will we see a meaningful advance in solar technologies of all types.

Solar Energy Part 1

2009-05-25T14:37:00.001-07:00

Solar Energy – Today and Tomorrow (I)

Solar Energy…. It has a nice ring to it, doesn’t it? The answer to humanity’s need for energy, limitless, perfectly clean, harness the awesome power of the sun… all sounds grand. As with most subjects, it is both right and off base.

Solar energy can be broken into two components, and we will look at each separately. Generating electricity from solar energy is called photovoltaics, or PV. Using the sun’s heat to generate useful energy we will call solar heating, SH.

Let’s look at PV, or photovoltaics first. Scientists are able to measure the solar energy which strikes the surface of the earth quite accurately. At our current rate of consumption, the solar energy falling on one half of Manitoba is enough to meet all of the worlds’ energy needs. So research is focussed on how to increase the output of PV cells, how and where to locate them, and how to store and distribute energy when the sun is not shining.

Many of you have, or have seen PV devices. You may know them as “solar powered”… the essential component is a small window, usually grey or blue, that converts light into electricity. Some calculators and watches have a PV cell to run them, and your local auto supply store sells panels which will recharge your car battery or run a small electronic device. Solar powered radios and patio lights are also popular. All those devices work because as a photon, a unit of light, strikes the treated silicon layer inside the cell, it knocks loose an electron. When you have enough loose electrons you soon have a usable electric current. The big problem with these devices is their efficiency, or rather lack of it. A PV cell, on a good day, converts only about 15% of the sunlight that strikes it into electricity. When you include clouds and atmospheric dust, you don’t get a lot of electricity out of your cell. On the good side, huge strides have been made in recent years to advance this and experimental efficiencies of over 40% have been demonstrated. This compares with nature’s efficiency of over 95% when converting sunlight to chemical energy using photosynthesis by plants

Scientists figure that in places where there is a lot of sun and electricity is expensive, such as Italy, California and parts of Japan, PV can compete with traditional generation methods within a decade. There is a working PV system near Springerville, Arizona, that covers an area of about 50 acres. It is built so that standard modules of about one acre in size can be added as needed, and it generates 4.6 megawatts, enough to power about 3900 homes, perhaps one third of Brockville. The best part is that it does this with no emissions whatever. Even with the low efficiency of PV, maintenance and wear and tear is minimal. In our part of Canada however, with relatively cheap electricity (about 6cents/kwh) and less sunshine, PV remains marginal, powering channel markers on the Seaway, for example.

The German government is encouraging PV development by allowing producers to sell PV power to the grid for up to three times the cost of electricity generated by conventional means. This is creating a boom in technological innovations in PV. A really cool development involves a PV cell that is created by a special version of an ink-jet printer, and is laid down on a flexible sheet only a millimetre thick.

The next issue with PV is that our need for electricity and the times the sun shines do not always match, so you have to have some kind of storage and backup system. Weight and space requirements for these can be considerable. Batteries to power your house for 24 hrs. or more would be as big as your kitchen stove. Current research is tending towards compressed air in which the PV system powers compressors when the sun is shining, and the compressed air drives a turbine when it is dark. Underground caverns previously used for natural gas storage are being considered to store the compressed air.

So, to get our moneys worth out of PV, and scale it up to make it economical, we can do either of two things… set up in a desert location, preferably near the equator, and take advantage of clearer skies and a more consistent solar angle, or hoist the whole thing into space.

As to putting the whole thing into space, there are obvious technical challenges associated with getting that much hardware up there, and assembling it, but it is technically possible. Increases in efficiency of factors of three to five are thought possible because of the lack of an interfering atmosphere and the ability of the panels to face the sun continuously. The power would be beamed back to receivers on Earth in the form of microwaves. If this project were to be started tomorrow we wouldn’t be seeing any “space-generated” electricity for at least twenty years, and then at a considerable cost, but largely pollution-free. Dozens of necessary shuttle launches may make this option less attractive. This or comparable plans are unlikely to be implemented until fossil fuels are in critical short supply.

PV is on the verge of huge growth, and we can expect to see a lot more of it in all areas of the globe over the next few years. Next week we will look at solar thermal power.

Gluten

2009-04-25T17:48:00.001-07:00

Gluten – Essential for Bread, possible Allergen

A friend mentioned to me that her granddaughter had recently been diagnosed with celiac disease, and that she was allergic to gluten. My friend asked me about gluten, and how she could spot it in foods and what to avoid. I have no wish to step into the territory of my medical colleagues, but there is quite a bit of science and chemistry associated with gluten which we can explore.

First, let’s look at the basic grains that have formed the staple food of most of humankind for thousands of years. These are wheat, rye, oats, barley, sorghum, maize (corn) and rice. Quinoa is a new (to North Americans) grain that is gluten-free. Only the first two of these yield a flour that gives bread the taste and texture we have come to want and expect. All of these seed grains consist of three parts: the embryo, which is the seed of the new plant, the endosperm, which is the store of nutrient for the developing plant, and the protective coating of the seed which ends up as the bran. In most seed grains the endosperm makes up about 80% of the bulk of the seed. This is what we make into flour, and flour consists of protein and starch. About 85% of the proteins in wheat, barley, and rye flour are responsible for dough formation, and are collectively known as gluten.

Flours from different types of wheat have different protein levels and dough-making characteristics. North American spring wheat, Canadian style, is described as “hard” by the millers as the endosperm is brittle and grinds easily. This makes an excellent bread flour. “Soft” wheat, usually made from winter wheat and more common in Europe, makes a better cake and pastry flour, where a more crumbly texture is desired. All-purpose flour isn’t, as any good baker can tell you. Interestingly, the bread-making properties of flour are improved by storage, and year-old flour will make better bread. However, most flour we buy today has been chemically aged.

So to gluten… as we noted above, glutens (there are two types) are found in the protein component of wheat, barley and rye. Because many of our foods contain flour made from these grains, people with a gluten allergy have to be very careful about their diet.

Some of the main sources of gluten in our diet are bread, pasta and cereals, biscuits, cakes pastries, some sauces and soups (which use flour as a thickening agent), vegetable oil which may be made from or contain wheat germ oil, many snack and fast foods, and beer and whisky (Rye and Scotch). American whisky is made from corn and should be acceptable. Not helpful for an eight year old, I realise.
Foods which do not contain gluten are fruit, vegetables, salads, potatoes, rice and maize (corn), nuts, red meat, chicken, fish, eggs and dairy products, and wine and cider. Potato flour or rice flour can be substituted for wheat flour, but you may not get quite the texture you have come to expect from wheat flour. Using cornstarch instead of flour to thicken sauces and gravy is an example of an easy change.
Two local nutritionists have written several recipe books with many delicious-looking recipes for gluten-free cooking. For more information, check out their website at www.bestbreadrecipes.com.

Recent research at Agriculture Canada has proven that oats are safe for celiacs. The problem is contamination from milling equipment, so look for oats milled in a gluten-free process, which are available in some health food stores.

Now we get to the effect part… the inside of the small intestine, the section right after the stomach, is lined with millions of tiny fingers called villi. These villi absorb the nutrients in the food you eat, the iron, the vitamins and minerals, the proteins etc. If you have celiac disease, your body, on exposure to gluten, produces antibodies that damage and ultimately destroy these villi. As you can imagine, this process inhibits your body’s ability to absorb nutrients. Because the symptoms are rather non-specific, you can function for quite a while, often years, without realising what is wrong. You may simply feel tired, have bowel problems, be anaemic, and have a bloated stomach. A simple test might be to remove gluten from your diet and if your condition improves over a few weeks or more, you may have an allergy. On the good side, the damage to your intestines often is reversible when gluten is removed from the diet. Without going into a long medical description, suffice it to say that if there is a gluten allergy in your family your likelihood of having the allergy is increased considerably, and if you think you may be allergic you should consult your doctor for guidance in your specific case.

It is estimated that about 1 in 300 North American and Europeans suffer from celiac disease at some level.

More and more packaging information indicates the presence of gluten, although declaring gluten on the label is not mandatory. The Beer Store now carries a gluten-free beer, and some beers are made from rice. Restaurant meals can be a bit of a problem, and it is advised to develop a relationship with your chef so that you can specify a non-gluten containing alternative. Most will try to accommodate you. Being careful and avoiding certain foods can allow someone with celiac disease to lead a normal healthy life.

Caffeine - Our Love-Hate Relationship

2009-02-18T16:45:00.000-08:00

Caffeine is one of those chemicals with which we have a love-hate relationship. Many of us enjoy a good cup of coffee in the morning and some can’t function before their second cup. Others find that the side effects are too much to bear and they forsake it altogether.

Let’s take a more detailed look at caffeine and understand its benefits and drawbacks.

Caffeine is a stimulant that works on the brain to cause it to release adrenaline, and to raise the body temperature slightly. This causes a heightened sense of alertness and readiness to act. As well, caffeine indirectly causes the liver to release more sugar, giving a sense of increased energy.

Caffeine is found in coffee, as we all know. It is also in tea, cola, chocolate, and several medicines. The amount in these sources varies greatly. It is classed as an alkaloid, a group of chemicals found in plants which are the basis for many medicines.

Coffee is the most readily available and identifiable source of caffeine. The coffee bush, the source of coffee beans, is native to Ethiopia, and its cultivation has spread around the world. It is claimed that drinking coffee or a coffee-like beverage began in the Arabian area around 1100 yrs ago, and gradually spread to Europe in the 17th century, and then round the world. It is claimed that coffee is the world’s most popular prepared drink (water being more popular), and world production of coffee is enough to provide one cup per day for everyone on Earth.

How much caffeine, you ask?
· 1 cup of coffee contains about 150 mg. (milligrams, one thousandth of a gram) caffeine.
· 1 cup espresso contains about 100 mg. caffeine (but in less than half the volume of a regular cup).
· 1 cup black tea (the kind most of us drink) contains about 20 – 75 mg, depending on the brewing time. By weight, tea contains more caffeine than coffee, but there is less caffeine in a cup of tea because of differences in the method of brewing.
· 1 cup green tea contains 5 – 20 mg. caffeine.
· 1 cup cola drink contains about 50 mg caffeine.
· 1 dark chocolate bar (about 50 grams of chocolate) contains about 75 mg.
· 1 milk chocolate bar about 50 mg.
· Anacin analgesic contains 64 mg per tablet.
· Excedrin contains 130 mg per tablet.
· Dristan contains 30 mg per tablet.
· Many cold medicines contain caffeine. If you are concerned, read the list of ingredients carefully.

Some of the negative side effects of caffeine are that it is a diuretic (it makes you pee) and an appetite suppressant. Probably not bad for some of us, so generally the benefits outweigh the negatives. Also, if you suffer from high blood pressure caffeine is not good, as it may also raise blood pressure slightly.

As far as dosage is concerned, research and experience indicate that an average adult can consume up to about 300 mg without significant negative effects. Two to three cups over about four hours would be about the limit.

Shift workers, of whom I was one for several years, are great consumers of coffee, and it definitely assists you in getting through a shift and functioning at a time when everyone else is asleep.

Caffeine does not affect everyone in the same way. There are some people who can drink lots of coffee and work well, for others, even a cup or two can be too much. In fact, in a recent study, a group of college students was studied. Half were given a cup of coffee before bed, the other half were given warm milk. They were then asked to describe how soon they fell asleep, and how well they slept. Most of those drinking coffee said they took longer to fall asleep and slept restlessly, while those drinking the milk reported they fell asleep quickly, and slept well. In actual fact, the coffee was decaffeinated, and the warm milk was spiked with caffeine to the level of regular coffee. This shows the huge effect of perception and expectation.

Nevertheless… the lifetime of caffeine of the body is such that it is suggested you don’t drink coffee within four hours of the time you expect to hit the sheets.

Decaffeinated coffee uses a process of extraction to remove the caffeine. Because caffeine is water-soluble, it can be removed fairly easily from tea and coffee. The water that contains the caffeine and other water-soluble flavouring compounds is then treated with activated charcoal, which removes only the caffeine. The residue containing the flavours is returned to the coffee. However there are those who say that this process removes a portion of the flavour and that decaffeinated tea and coffee do not taste the same. A recently-developed process uses high pressure liquid carbon dioxide to remove only the caffeine. This is said to give a better-flavoured decaffeinated drink.

In recent years we have seen a rise in the sales of so-called energy drinks. You know the brands… the main ingredient in these, in addition to sugar, is caffeine, along with a few plant and herbal extracts whose efficacy is uncertain. These drinks may contain up to twice the caffeine found in a cup of coffee. So a drink of one of these may give you a jolt and see you over a hump, but caution is suggested.

For those withdrawing from caffeine or switching to decaf drinks, they may have headaches for a few days as their body adjusts. Some are able to go without and see no symptoms; others can suffer quite a bit. It varies greatly.

So coffee and caffeine-containing drinks can give you a boost, but like many things we eat and drink, if we consume them excessively they can have negative side-effects. Moderation is certainly the key.

NOTE: This is presented for informational purposes, and is based on information the writer believes to be accurate. For specific medical recommendations about your own case, consult your doctor.

Fats.. Good or Bad?

2009-01-10T18:52:00.000-08:00

FAT – GOOD OR BAD?

It is pretty difficult to pick up a paper or see the news today without seeing an item related to fat. Some kinds are good, some kinds are bad, how much is too much, how much you need, how much is in different foods, both at home and in restaurants. How can anyone make sense of all this information? Let’s start at the beginning and see if we can figure out some of the basics. There is definitely more than one column here!

Fats of all sorts are key components of our diets, and are necessary for a balanced diet. Fats are a way of storing energy, and it has been said that the love of fat that we humans seem to show originated thousands of years ago, before there were Superstores.

Fat is stored in the bodies of mammals as a way of storing energy for future needs. It is “burned” in the same way as we burn a candle, although there is no flame in a body, to produce heat. This heat keeps the organism alive and the carbon dioxide that is produced in the process is exhaled in respiration. Fat also serves as a very good insulator. Large marine mammals can live comfortably in freezing water due to their thick layer of fat and still preserve a warm inner body temperature.

Fats occur naturally and chemically they have several features in common. They belong to a family of compounds called triglycerides that you may have heard of. Think of a triglyceride as a tiny capital E, with the three branches made up of a chain of carbon atoms of varying length. If all three branches are 16 carbon atoms long, you have palmitic acid, found in olive oil. It is called an acid because of the carbon and oxygen atoms on the end of the chains, not because it dissolves metal. Changing the length of the carbon branches to 12 carbons gives lauric acid, found in coconuts. So the length of the carbon chain, and whether all three branches are the same gives the fats their unique properties. Natural fats and oils are almost always mixtures of several fats.

Now it gets a bit complicated, so please bear with me. If we think of these branches as a chain, palmitic acid would have 15 links, with one extra carbon for the acid group. Some fats however, have a double bond in the chain… think of it as two links of the chain side by side, with the overall length unchanged. This double link means that the physical properties of the fat are changed, and generally more double bonds mean liquid oils, and fewer means solids such as lard and butter. Years ago, chemists discovered that they could add hydrogen to these unsaturated fats, and turn liquid oils into solids that were easier to store and did not spoil. So this is where the terms saturated, or hydrogenated, and unsaturated fats originated.

In a fat such as butter, these branches are very short. This means that butter melts at a very modest temperature, about 30 deg. C. It also means that butter can easily be scorched and the molecule broken down at higher temperatures, which is why you would not use butter to make French fries.

Let’s take a look at a recent trend … omega-3 fatty acids. In chemistry we use various Greek letters to tell us where those double bonds that I mentioned above are located. As you would expect, omega-3 fatty acids have their double bond in a very specific location on the carbon chain, third from the end, and this gives them unique properties. First, there are two common ones, known mercifully by their initials as DHA and EPA. There is another common one known as ALA, which we will come back to. DHA and EPA are found in fatty fish such as salmon, tuna, mackerel, and sardines. These fats have been linked, and I use that term reservedly, to benefits such as a lower risk of heart disease, cancer, Alzheimer’s, and several other health problems. So food manufacturers, quick to spot a trend, are claiming that their food contains omega-3 fatty acids, or they have added omega-3 to their product. However, make sure you read the fine print, because ALA which I mentioned above has almost no demonstrated benefits, but is cheap to produce and add to foods. If the label doesn’t clearly mention DHA and EPA, it is likely the ALA acid, and the claim, while technically correct, likely results in minimal or no benefit. As well, check to see how much is in your food. With some foods you would need to consume enormous quantities to get the same amount of omega-3 that could be obtained in one portion of salmon, for example.

So what is a consumer to do? My colleagues in the nutrition field will probably recommend a balanced diet, with minimal fats and sugar, and several portions of fish, and lots of fruit and vegetables, along with adequate exercise. That approach will give you the best health benefit. That is my objective, and along with carefully reading the label and taking advertising claims with some scepticism, I hope to enjoy a long life.

Insulation--Warm Inside and Out

2008-11-20T18:07:00.001-08:00

With colder weather approaching we are giving more consideration to heating our homes now, and to keeping ourselves warm. This week we are going to look at insulation, to see what the numbers mean and understand how it works.

Let’s look at heat, and see how it works. Heat moves via three modes: conduction, convection and radiation. Conduction is you touching something hot directly. Convection involves a medium such as air or water, and heat is carried from one place to another by that medium, such as the warm air coming out of your register. Radiation is how the earth is warmed by the heat of the sun even though there is no air or other medium to carry the heat directly to us through space. The inside of your furnace employs all three of these methods to get the heat to where you want it.

Under the laws of thermodynamics, heat flows “downhill”, or it goes from a hot area to a cooler area. In winter, the outside of your home is cold, and you want the inside to stay warm, so you need a furnace or heater to generate heat inside your home. This heat tries to escape through all the exterior walls and surfaces of your home. Insulation slows this process down and allows your home to stay comfortable. What kind and how much insulation you have will dictate how fast this process is, and how much your furnace has to work to keep your home comfortable. As well, heat rises, so to retain that heat within your home you need more insulation in the ceiling than in the walls.

Most of us are familiar with home insulation, in the form of the pink batts (the 15 X48 in. panels) and the Styrofoam panels, and we have a vague idea about the R number, in which more is better. What does this number mean? It refers to the rate at which heat flows through a certain thickness of material; because it is a reciprocal, a higher number is better than a lower number. It originated before metric units existed so it is based on BTUs (British Thermal Units, a way of measuring the quantity of heat) per inch per time unit. Europe uses a U value, in which lower is better.

Insulation works by trapping many tiny pockets of air within a structure of some kind. These pockets are separated from each other and each acts as barrier to the transmission of heat. Fibreglass, Styrofoam and blown cellulose all share this property. The foamed urethane that you can spray into the cracks around windows starts as a liquid but as the polymer forms and hardens it gives off carbon dioxide gas which becomes trapped in tiny cells, giving the insulation value. Another key property of insulation is its non-flammability. Fibreglass is non-flammable, and blue and pink Styrofoam is treated to be non-flammable. White Styrofoam, also called beadboard, has to be covered with a non-flammable layer, often plasterboard, to meet building codes. Blown cellulose is made from waste newsprint and is treated with chemicals called borates to resist mould, rodent damage and to reduce its flammability.

Fibreglass insulation is made from glass in the same way as cotton candy. It is heated to melting and spun through fine holes to make fibres. These fibres are collected and formed into batts and treated with a non-flammable resin to holds them together. Interestingly, FG insulation can use recycled glass, including coloured glass, which is often difficult to recycle. Some brands contain up to 90% recycled glass.

In the post-war building boom of the 50s and 60s, energy costs were not a consideration and thousands of homes were built with 4” cavity walls with minimal thought given to insulation. As energy costs rose in the 70s we began to see more attention paid to this area, and better methods of insulation and stricter codes came into effect. Today most new homes have 6” walls with a minimum R12 and often R20, and higher in the ceilings. Many of those older homes have been successfully retro-fitted with improved insulation to lower the heating costs.

Choosing the right insulation can be a bit daunting. As far as strict efficiency goes, pink or blue Styrofoam boards have the highest R-value per inch, about 5, with fibreglass and cellulose about R3.5 per inch. This however does not factor in cost and ease of use, which are major considerations, especially in retro-fitting an existing building.

An effective method of insulating windows is to use transparent shrink film, held in place by double-sided tape and tightened with a hair dryer. This traps a layer of still air in front of the window and lessens dramatically the amount of heat that escapes through the window, as well as blocking drafts around the window. Your home fix-it store has economical kits to do this.

With warmer summers now common, many of our homes are air-conditioned. The same principles apply as in winter, except the heat is trying to go the other way. Your air conditioner is removing heat that makes its way into the building, or is generated inside. That is why you turn off unnecessary lights and use the microwave instead of the stove when you are running the AC, and a well-insulated home is easier to air-condition as well as heat.

Canadians have an intuitive feel for insulation, and we must do a better job of minimising our consumption of energy. If we apply insulation carefully, to make best use of its properties, we can make significant progress towards energy conservation and save money as well.

Plasticisers - Good or Bad?

2008-11-02T16:40:00.001-08:00

PLASTICISERS – GOOD OR BAD?

A reader commented recently that she had heard that the plasticiser used in water bottles could be toxic and find its way into the water. This is a very timely question and one that I had considered but was unable to fit into my previous column. Let’s take a more detailed look at this complicated story.

First, what is a plasticiser? Many polymers contain additives to give them desirable properties such as colour, resistance to UV and heat (the enemies of polymers) and sometimes more or better flexibility. For example, we have seen the turquoise pipe made in Prescott for water pipes. It is made of polyvinyl chloride, or PVC, and is very hard. PVC is the same material that your swimming pool liner and your raincoat is made of, but they contain a plasticiser to make them flexible. So a plasticiser acts as a lubricant between the very large polymer molecules, enabling them to move against and past one another, and giving flexibility to the finished product. Sometimes plasticisers are added to make a polymer easier to process, such as in making wire insulation.

These plasticisers take many different chemical forms, depending on what polymer is being processed and what end-use is sought. A very common plasticiser is called dioctyl phthalate, or DOP for short… we won’t worry about the formula for now. DOP is used extensively in flexible PVC polymer, the kind consumers encounter frequently in waterproof clothing, pool liners and many other applications. DOP is considered safe… more about that in a moment. For food handling and packaging applications, plasticisers are based on citric acid, the most common of which is called tributyl citrate.

As I mentioned above, most plasticisers are used in PVC plastics. Water bottles are made of polyester plastic, or PET, and according to my research and to the manufacturers, do not contain plasticiser. Most common food-packaging polymers, such as polyethylene (milk bags), polypropylene (yogurt and ice cream containers) and polystyrene (clear clam-shell containers and foam plastic containers) are made without plasticisers. There is a catch, of course. When a polymer is made and all those tiny molecules are linked to make a large polymer molecule, not all the small molecules become incorporated into the polymer. This material, called monomer, may be soluble in the food, or may be volatile (evaporates) and this could be a cause of concern to some consumers.

I have read about claims that freezing a water bottle to keep your lunchbox cool and enjoying ice water at 3:00PM can increase the amount of plasticiser in the water. This is wrong on two counts – first, there are no plasticisers in water bottles, and second, in almost all physical and chemical processes, a lower temperature slows things down. Researching this in the 70s regarding plastic milk bags, we placed milk in bags at 35 deg. F., (fridge temperature), at 70 deg. F., (room temp) and at about 150 deg. F., (microwave temp). In every case more monomer (not plasticiser) migrated to the milk as the temperature increased, although none at a level thought to be harmful. So freezing your water bottle is not going to cause any health risk.

Now we get to an interesting component of this story. Some of this information and misinformation has been swirling around the Internet for a while, and as you know it can gain a life of its own. A thesis by a student at the University of Idaho claimed that chemicals were leached from water bottles into the water, and this was widely quoted. The problem is that this was not a peer-reviewed scientific study, one in which scientists familiar with the subject examine the work and determine if it was done to the highest technical standards A subsequent review of the student’s lab work revealed significant gaps and unacknowledged sources of error, yet the so-called study continues to be cited.

Back to DOP, the common plasticiser in PVC. In the chemical world, there are many chemicals that have been in common use for years. As knowledge and better testing advances, some of these are removed as we realise their harm, such as asbestos for insulation and phenol as a disinfectant. Others we substitute using a less harmful equivalent material, such as using HCFCs instead of the original fluorocarbons. With others we change the amount or the application as we refine our understanding of how they work. DOP comes in the latter category. It has no known connection to cancer or any adverse health effects, but it is being monitored to determine if it is being over-used and a better substitute can be used. This is a long-winded way of saying that medical science knows of no long term serious effects of exposure to DOP, but that doesn’t mean they don’t exist.

So where does all this leave us? Food packaging material is extensively tested under a variety of conditions, and is very safe. It has significant benefit to the consumer by keeping food clean, maintaining freshness and minimising waste. If you as a consumer are concerned, you can of course purchase your food fresh and have it wrapped in paper or polyethylene bags and wrap. My guess is that you will not see a difference.

Bottled Water... Not so convenient

2008-09-30T18:21:00.000-07:00

BOTTLED WATER

Bottled water has become rather controversial lately, for several reasons, so I thought we would take a look at it and understand the issues and what we can do about it.

First, let’s look at the water. In Brockville, as in all municipalities that operate water systems in Canada, the water piped to your home is very safe. The Ontario Ministry of the Environment has stringent regulations in place to see that it is clean and free of materials that may cause harm. These include e coli, which are the bacteria found in sewage and surface water, that can cause stomach upsets and more serious effects, solids which can affect taste and clog piping systems, and various organisms and particles that may cause health or taste issues. As well, there is a comprehensive list of organic compounds, many related to pesticides and fertilisers that are monitored and controlled. Testing is done frequently, on a directed schedule, to ensure the continued safety of the water. Your water may have a faint chlorine taste because a small chlorine excess will ensure that no harmful organism reappears in the water during distribution.

Bottled water in Eastern Canada comes from several sources, according to my unofficial survey. Feversham in Grey County is a common spring that is bottled, Aberfoyle near Guelph is widely bottled, and Hope Springs in B.C. is another. Bottled water comes under the jurisdiction of the Canada Food Inspection Agency, and stricter regulations are being considered by Health Canada, but are not yet in place. Water advertised as mineral or spring water may not be treated before bottling, but simple “bottled water” may be merely filtered or treated municipal tap water. Most brands will give a mineral analysis on the label and there is usually a small amount of carbonate, sodium, potassium, calcium, magnesium, and sulphate in the water, at parts per million levels. These are not harmful and impart some flavour to the water depending on their concentration. The water is not monitored for the wide range of compounds as tap water, perhaps because we have an idyllic view of a “spring” being naturally pure and uncontaminated. Ozone or ultra-violet light may be used to kill bacteria. Ozone, you may recall from a previous column, is a three-atom molecule of oxygen, and it has germicidal properties like chlorine, but with no aftertaste. So ozonated water may be perceived as more sterile than non-ozonated water.

Let’s take a look at the cost. Brockville City water costs about 0.06 cents per litre, based on an average family’s consumption. A 500 ml. (the common size) bottle would cost about 0.03 cents from your tap. So if you pay $1.00 in a vending machine, and you would be lucky to do so, you are paying over 3300 times the cost of the water, less the cost of the bottle. This is over twice the cost of gasoline, and we sure complain about that. Even when you buy a case at the supermarket, and you pay about 15 cents per bottle, you are still paying many hundreds of times the cost of the water. Heck, good rye whisky isn’t much more!

Now the bottle… water bottles are made of polyester, or PETE. This is the same polymer that is used to make videotapes and cotton/polyester clothing, among many other products. It is quite readily recycled, with the reservations I mentioned in a recent column. However only about a third of the water bottles end up in the blue box. Those that are recycled have been successfully turned into polar fleece and reusable shopping bags, and automotive and industrial carpet fibre is another promising outlet. The numbers of these bottles that are used is staggering, and most end up in litter and roadside trash.

There are a couple of other key points in this debate. A student who chooses a bottle of water over a bottle of pop in her school cafeteria has made a more healthful choice, but do we need “designer” water from Fiji, or from a rapidly-disappearing glacier? Sure, Perrier and Pellegrino and a few others have been around for quite a while, but they were originally conceived to be served at a table. We can easily purchase a more robust (polycarbonate or aluminium) water bottle, rinse and refill, and meet our needs for portable water. Careful cleaning is necessary, of course. Some municipal water does have a discernable taste which some may find unpleasant, but that can easily be removed with one of the readily-available filter systems that is effective, economical, and easy to maintain. Transporting all that water around the country burns prodigious amounts of diesel fuel, contributing to carbon dioxide and soot, and with water weighing one kg. /litre, in a legal truckload of about 38000 kgs. there is space left in the cargo area. According to both Health Canada and the bottled water manufacturers, the shelf life of sealed bottled water is two years if it is stored in a cool dark place.

The United Church of Canada and David Suzuki have both registered their opposition to the widespread use of bottled water, and conscientious consumers may wish to lower their use of bottled water and make choices with less environmental impact.

Polymer Recycling

2008-08-09T17:55:00.000-07:00

An issue that pops up from time to time is related to the recycling of plastics… can it be done, is it economical, how do you do it and what do you get?

Let’s take a look at this subject and see what some of the issues are and what we as consumers can do about them.

First, what is a plastic? Most people understand the word “plastic” to mean something sort of light, flexible, non-rusting and maybe cheap. In the chemical world we use the word polymer, which means “many units”. Polymers are typically made from small molecules containing carbon, which are attached to one another by chemical processes to make very long chains. The chains can have other atoms such as hydrogen, oxygen and nitrogen in them as well. It is the length of these chains, and the way in which they fit with each other that give polymers their interesting and useful properties, such as resistance to water or oxygen or fuels, ability to be formed, coloured, drawn into fibres, extruded into films, act as an electrical insulator and many other applications.

Polymers generally have two main enemies: heat and ultraviolet light (sunlight). This is why your plastic lawn chair goes brittle after about three summers. The heat and UV act to break the long chains into smaller fragments. This weakens the polymer and soon it will fracture or crumble, and the object made from the polymer is no longer useable. Some things can be added to the polymer to protect it from heat and UV, such as carbon black pigment, or special compounds called antioxidants, which will extend its life.

So now we get to the recycling part. We collect water bottles, grocery bags, and margarine and yogurt tubs and put them in the blue box, but what then? All of these will have been exposed to some heat and UV and they will not be as strong as when they were made. As well, by the blue box stage they are all contaminated with labels, adhesive, and of course residue of what they contained. Another issue is that not all polymers are alike in that the items I mentioned above are all made from different polymers that cannot be combined. So, there have to be several processes: separation, cleaning and sorting, and then upgrading of some kind to make them useable.

Now, another part of the problem: many polymers are used in food packaging and medical applications, where contamination of any kind is unacceptable, and some applications such as fibre spinning require a very clean polymer. So you can already see the problem emerging: every time you recycle a polymer, you essentially downgrade a step or two. If you are making plastic municipal garbage cans or park benches, you have a lot of polymer to choose from, at a very reasonable price. Food wrap and intravenous tubing requires top quality material, and as a society we seem to want more food wrap and fewer municipal garbage cans.

Another issue is this: pick up your full blue box (without glass jars in it) and you will see it is pretty light. Waste polymer is mostly air, and until you can crush it or grind it or make it denser it takes up a lot of space for not much material, so shipping costs can be high.

So where does all this take us? Good quality waste polymer is a useful commodity and can command a high price. But it required extensive and costly sorting, cleaning and general upgrading to get there. Lower quality recycled polymer, with more contamination is of considerably less value. Our manufacturing system has incorporated economies of scale such that virgin polymers such as Styrofoam and low density polyethylene are only slightly more expensive than recycled material so there is little incentive to recycle these. PET (water bottle polymer) is of higher value and recycling these is more economical.

The grocery bag you took home from the supermarket the other day weighs about 5 grams. The recycle industry will pay about $.25/lb. for this material… so you need 100 bags to make $.25 worth of polymer for recycling, and only then if you have a truckload of it.

Used tires present a special case. Recycling rubber is already a thriving business, and most truck tires have treads made from recycled rubber. There are several ways to deal with used tires that are proven: they can be shredded and added to new rubber to make new tires and other rubber products; they can be shredded and added to paving material after the steel wire is removed; they can be added to the fuel used to fire a cement kiln, as these are fitted with effluent control; they can be heated in a vessel with a low oxygen atmosphere where the rubber breaks down into an oil-like material that can serve as fuel or be added to a crude stream. These technologies are either commercial in scale or at least proven in trials.

There is a class of polymers made from cellulose, corn waste, sawdust, and other renewable materials that we will look at in a later column.

As consumers we must demand more recycled content in the areas where it makes sense, and do as much as possible to clean, sort and recycle our polymer waste. We can influence the marketplace through our choices and our purchases. Let’s try to make reasoned choices and work to lower the amount of polymer waste we generate.

Carbon - Carbon - Carbon

2008-07-11T15:32:00.000-07:00

CARBON – CARBON – CARBON

There is a lot of talk about carbon today… we hear of carbon credits, carbon offsets, carbon caps or limits, carbon sequestering, carbon footprint, and that is just the beginning. These are all related to lowering carbon dioxide in the atmosphere, by technological means or changes in the way we do things or organise our affairs. Let’s take a look at one of these and understand what it means, and what effect it can have.

Carbon offsets are in the news and the public eye, so let’s see what they are about. My wife and I recently went on-line and booked a pair of return air tickets to Calgary; the process was pretty straightforward. Then we came to a question: Did we wish to purchase a carbon offset? Naturally being rather inquisitive, I took a look to see what it was about.

First we have to back up slightly. Remember a few columns back I mentioned that the burning of fossil fuels is the main contributor to the build-up of carbon dioxide in the atmosphere? Carbon offsets are meant to lessen or remove a portion of each individual’s contribution to the carbon dioxide load, by doing or supporting something that removes carbon dioxide from the atmosphere. In Canada, this typically means planting trees. So, Air Canada figures that flying two adults to Calgary and back generates about 1.2 tonnes of carbon dioxide, and that, if we wish to pay it, they will give $19.20 on our behalf to an organisation called Zerofootprint (www.zerofootprint.net) who will plant enough trees to absorb that much carbon dioxide. Zerofootprint’s website has enough detail on carbon offsets to satisfy everyone’s curiosity.

Although there are several issues associated with this approach, it is clearly better to do something than nothing. For example, there is considerable disagreement about how much carbon dioxide is absorbed by a tree growing in Canada vs. a tree in a tropical forest. You may have seen the R and T article on Aug. 14, in which the Ontario Government promises to plant 50 million trees to “soak up” 3.8 million tonnes of carbon dioxide, or 76 kg/tree. Another reference I found indicates 560 kg/tree. As well, we want to ensure that the offset is incremental, that is, they use my $19.20 to plant extra trees, not just buy a truck to haul the trees. How long before those trees soak up the 1.2 tonnes from my trip? Is there enough space where trees can be planted to account for my and other Canadians travel requirements? Can or should we differentiate between essential travel and discretionary travel? I read recently that flying to a tropical island in February so you can lie on the beach may become socially unacceptable as people become more aware of their individual impact on carbon dioxide levels.

Air Canada’s claim of 1.2 tonnes is backed up by solid evidence, as they fly a lot of people to a lot of places, and they have very detailed information regarding fuel use, load factors etc. Air Canada is doing their part to lower their carbon footprint by employing more fuel-efficient aircraft, using weight reducing strategies, and managing their fuel usage more carefully. Some other carbon offsets may be based on more speculative data, but as I mentioned above, it is clearly better to do something than do nothing.

From an industry perspective, there are a lot of strategies in place. Carbon can be traded just like other commodities. If an industry produces X tonnes of carbon dioxide per year, and implements technical and operational changes that lower this to 80% of X, they can then “sell” their 20% saving to someone who is willing to pay, less a small portion that is “retired”, that is, withdrawn from the overall amount of carbon dioxide that is discharged to the atmosphere. The purchasing industry may be winding down, or in the process of updating their process, or struggling with out-of-date equipment, or all of these. The marketplace seems to decide how much a carbon offset is worth, and as more people become aware and concerned about the issue, this value is only going to increase.

As you can tell, right now this process is voluntary, at least at the consumer level, but in the coming years we will likely see guidelines and regulations coming into force, and offsets may be applied to personal transportation and other activities over which we, as individuals, have control.

Carbon offsets are one of many means we have to reduce our carbon footprint, that is, the amount by which each of us, through our everyday activities, adds to the carbon dioxide level in the atmosphere. It will require a concerted effort to by industry and government to make this work, because ordinary people will be very resentful if they are doing their best regarding carbon dioxide reduction yet significant contributors in the public and private sector are being seen as getting away with uncontrolled generation.

Lightning - The Big Strike

2008-06-14T18:35:00.000-07:00

The summer thunderstorm season is upon us and it might be helpful to take a look at lightning and understand some of the ways we can protect ourselves.

Lightning is one of nature’s most awesome displays and one of its more dangerous, and most misunderstood. We are in the middle of summer, traditionally the time of powerful thunderstorms that boom and crack and pour, and are gone in a few minutes. Behind they leave cracked and downed trees, power outages and sometimes injured bystanders.

Lightning has a long history with mankind… think of the metaphors usually associated with speed, and the use of lightning bolts as symbols of power.

Let’s take a look at lightning and see what it is about. Lightning is electricity… not exactly what you get when you flip on the light switch, but more like the kind you get when you shuffle across the carpet and touch the doorknob, but hugely amplified. It is estimated that a lightning bolt operates at many millions of volts, and generates temperatures of several thousand degrees. Scientists, including electrical engineers, and meteorologists are not in total agreement on what lightning is, but seem to agree that inside the huge upwelling clouds that typically occur late on a hot summer day, there are very strong currents that move water droplets, dust particles and ice particles rapidly up and down. This process causes the droplets and particles to become either positively or negatively charged, and the clouds will end up with a huge voltage differential between the top and bottom. The charge at the bottom of the cloud, a few hundred metres from the ground, will try to neutralise its charge to the nearest ground, and that will typically be a tall building, an antenna or a tree.

What happens then is a small “leader”, a relatively weak discharge, tracks upward from the ground to the cloud, and the really big strike follows the path created by the leader to the ground. The big flash, the burned and split tree, and the noisy crack then follow.

The rumble of thunder is caused by the bolt superheating a channel of air that surrounds it. The closer the flash and the boom, the closer the actual bolt is to you. One mile per five seconds of delay is the general rule.

Not all lightning is cloud-to-ground; there is what is called “heat lightning” or “sheet lightning” which is cloud-to-cloud discharge, as well as discharges within the same cloud.

The damage caused by lightning can vary greatly. We hear of many cattle being killed by a single strike, yet people have survived strikes with little more than some minor burns. Huge trees may be split from top to bottom, others lose a few branches. A chain may be fused into a single piece, and a fine necklace may leave only a small burn mark.

The old wives’ tale about lightning never striking twice is just that – an old wives tale. The Empire State Building in New York City is struck about 25 times per year. One unlucky park ranger in the US has been struck seven times, and is still around to talk about it!

According to Environment Canada, lightning kills about six Canadians per year and injures about 75, as well as causing numerous forest fires. Windsor seems to be the “Lightning Capital of Canada”, with up to 250 strikes per year in the city. Ottawa records about 90.

There are a number of things you can do to protect yourself in the event you or your group are caught in a storm where there may be lightning. The first thing is to have a plan as to where to shelter, and assign someone to monitor the weather and report any approaching storm. Under a tree is not a good place to seek shelter, but inside a sturdy building, an automobile or bus is generally safe. Open vehicles such as a golf cart or an ATV are not safe, as it is the steel bodywork that protects you. Do not use a telephone, the water taps, and turn off the TV. If you are caught outside, try to find a low-lying area such as a ditch or hollow. You’ll be wet but safe. Crouch down, and if you are part of a group, separate yourselves. Make sure you remove your I-Pod and any earphones you are wearing, and turn off your cell phone. There is no evidence to suggest that I-Pods or cell phones “attract” lightning, but wiring and metallic objects can act as a pathway. Stay well away from steel fences and antennas. Golfers should not wave their 9-iron angrily in the air, and most courses will call golfers in if a lightning storm is approaching.

One interesting product of lightning strikes is something called a fulgurite (fulgur is the Latin word for lightning). A fulgurite is a tube of fused and melted sand formed by the heat of a lightning strike, and it looks like a gnarled branch, varying in length from a few centimetres to several metres, with a coloured glassy interior. They are typically found on beaches and in deserts. In what has got to be one of the world’s worst jobs, people in Florida pound steel rods into the sand at the beach when a lightning storm is approaching, then hope for a strike which will form a fulgurite, which can then be dug up and sold.

Lightning is one of Nature’s most dramatic displays, but you can lessen your danger by using a few simple steps and some common sense to protect yourself.

Organic - Or Not?

2008-05-17T18:02:00.000-07:00

ORGANIC – OR NOT?

The growing presence of and demand for organic food, in the form of produce, meat, dairy and even processed foods, is causing consumers some difficulties in understanding what the designation means and what they are getting for their money.
Let’s take a look at this as it applies to produce and try to understand some of these issues.

To start with, in the chemical world, organic means any compound containing carbon, regardless of its origin. As applied to food, if you were to ask a non-technical person, they might say that it means a food has more nutritional value, that it contains less pesticide residue, or that its production is better for the environment. All of these are at best only partly true, and often wrong.

Our local supermarkets have sections labelled “Certified Organic”, and our first reaction is that the produce sometimes doesn’t look as good as in the other section, and is often priced higher. First, let’s look at certification. Some producers call themselves organic without any form of verification. Others prefer to be audited, and earn the right to call themselves organic, by a body such as the OCPP (Organic Crop Producers and Processors), the FVO (Farm Verified Organic), or the CCOF (California Certified Organic Farm). At our local supermarket you will find designations such as QAI, ECO Certified, IMO Control, and USDA Organic. As you can see there are many qualifying organisations and sorting them out requires some research. To qualify for these designations, producers have to meet a set of standards related to pest (insect and weed) management, fertilizer use, irrigation and runoff management to name a few. The Canadian Government has a set of voluntary guidelines to which producers can adhere, but there is no current inspection mechanism.

A small example: the IMO Control program states that produce may be fertilised with manure or compost up to 120 days before harvest, that the manure must have a specific carbon to nitrogen ratio and be maintained at a certain temperature for 3 days prior to application. So you can see that the regulations can be very specific.

Our local supermarket reports that there is a small but growing demand for organic produce. The problems are that it tends to have a shorter shelf life, and therefore there is more waste, and the selection of items available is quite varied. These issues make it more expensive to carry. It is usually sourced from a warehouse in Ottawa, and as a consumer you can ask for locally grown produce.

Regarding nutritional value, there is no scientific evidence, despite numerous studies, to confirm that organic produce is nutritionally superior to that grown by conventional means. Organic growers will choose varieties of produce that are naturally pest-resistant, so there may be less pesticide residue on the harvested product. I say less because there is no way to control what is in the air or water that may end up on the produce, and conventional farming methods usually require that pesticides use is curtailed well before harvest. Having said that, no study has associated any known health effect with pesticide residue, and the overall benefit of eating fresh produce far outweighs any perceived harm. Taste is another matter, and many consumers report that organic produce tastes better. This may be a perception issue, or it may be related to the fact that the produce is generally fresher.

As far as farming practices are concerned, it is a mixed bag. Some organic farmers are using well water instead of surface water (streams or rivers) because the surface water may be contaminated with agricultural run-off from upstream. Fertilizing organic farms with cattle manure is acceptable, but run-off must be controlled and trucking organic manure many kilometres seems to defeat the spirit of the “small footprint” philosophy, even though it meets the letter. Organic farming is typically less efficient from a land use standpoint as well, in that productivity of an organic farm is about 75 – 80% of a non-organic farm. Rows have to be further apart, there may be a greater loss due to insects or birds, and hand-weeding is labour-intensive.

Then we get to the sustainability part. Another goal of organic producers and consumers is to grow produce in a sustainable way that uses less fossil fuels and chemicals in the overall process, and is less damaging to the land in the widest sense. Do we clear more forests for farmland because organic farming takes more area to produce the same yield? Does it make sense to grow organic potatoes in California then truck them many thousands of kilometres? Should we forgo asparagus in January so that we only ship and eat locally? Is it OK to store apples in coolers with a carbon dioxide atmosphere so we can have apples year round? The designation “organic” does not address these sustainability issues, yet as consumers we should be asking ourselves these questions.

Some people have reported a lessening or disappearance of some allergic symptoms when they switch to organic food products, but personal anecdotes do not constitute a controlled scientific study.

What can an individual do? Buying locally, from producers who ship their products a few to a few hundred kilometres, is probably a good start. Asking those producers how they grow their crops will help the consumer understand the complexity of the issue. Some farmers markets are “going organic” with only certified produce being sold. Overall the health benefit of consuming a variety of fresh fruits and vegetables from all sources is well proven.

Ozone Depletion and Global Warming

2008-04-28T06:30:00.000-07:00

A teacher colleague was speaking to me the other day, and she said that many of her students, high school, were confused about the terms and concept of the ozone layer and the carbon dioxide-global warming debate, including mixing up the two. Although they are related, there are separate issues involved.

Let’s take a look at these two issues… The ozone layer debate surfaced in the late 70s as satellite information revealed a large hole in the ozone layer over both of earth’s poles. What is ozone, and what does it do? Ozone is a special form of oxygen, written chemically as O3 . Normal oxygen, the kind we breathe, is shown as O2 . At ground level, ozone is bad news, because it is very reactive and contributes significantly to the formation of smog. Ozone is generated by internal combustion engines and other industrial processes and by lightning. In space, on the outer edge of the atmosphere, however, ozone serves the very useful purpose of protecting the surface of the earth from harmful ultra-violet (UV) rays from the sun. The ozone layer is not very thick, I have read as thin as a few centimetres, but it absorbs these UV rays nicely.

These holes that were found turned out to be caused by the reaction between ozone and chlorofluorocarbons, more commonly known as Freons®. These compounds were used extensively in aerosol propellants, refrigerators and air conditioners and plastic foaming agents, from which they easily escaped into the atmosphere.

In 1987, most countries, including Canada, signed the Montreal Protocol, in which they pledged to drastically reduce the amount of Freons used, and switch, where possible, to less ozone-damaging substitutes. This process has, over the last fifteen years or so, had the desired effect and damage to the ozone layer has been lowered considerably. Although gains have been made we must maintain our efforts.

This was the reason for the increased awareness of the need for sunscreen, especially in northern latitudes.

Now to the carbon dioxide issue, or Global Warming 101. Most of our industrial processes throughout the world, including transportation, power generation, manufacturing, and many others, rely on fuel to keep going, and mostly this fuel is something that is burned. It used to be wood, then (and still) coal, oil, natural gas, and of course gasoline and diesel fuel. Burning these fuels produces carbon dioxide, lots of it, about the same mass as the fuel burned. In pre-industrial times, there was about 200 ppm (parts per million) carbon dioxide in the earth’s atmosphere. It began to increase in the 19 century, shot up in the 20th, until we are currently looking at almost 300 ppm. This may not sound like much, and you and I can go about our daily lives not noticing any difference.

There are several other gases that contribute to the warming process, most of which are by-products of human activity, but carbon dioxide is the largest single contributor.

However, here is where it gets interesting… you know what a greenhouse is: an enclosed structure covered with glass panels. As sunlight passes through the glass, it is reflected back by the plants, wood and dirt within the greenhouse but at a longer wavelength that does not pass back out through the glass. The air inside the greenhouse becomes much warmer… good for the plants. As sunlight passes through the earth’s atmosphere, the higher carbon dioxide level in the atmosphere has the same effect as the glass panels on the greenhouse, preventing a large portion of the sunlight from being reflected out into space, and thereby warming the atmosphere. In February in Ontario, we may think this is a good thing, but we would be wrong. Significant changes in the atmosphere, including the increase in carbon dioxide and the other “greenhouse gases” can have very severe consequences to rainfall, snowfall, glacier formation, sea levels, sea ice thickness and duration to name a few. These in turn have huge consequences for agriculture. We won’t be growing bananas in Brockville any time soon, but if the places where bananas are grown today become deserts or are flooded by seawater, we have a problem. As well, many millions of people live within a few metres of sea level, so any rise will have catastrophic consequences for them as well as us. (Brockville is about 300 ft. above sea level, depending on where you are in the city).

We will take a look at some of these in more detail in another column, but my point today is that the ozone layer depletion problem, while not solved, is well understood and means are being implemented to address it. The global warming problem appears, by all scientific analysis, to be related to increasing carbon dioxide in the atmosphere, but because we seem to be wedded to carbon-based fuels, and with the industrial intensification in China and India, and the denial by many nations, businesses and individuals that there is a genuine problem, no near term lowering of carbon dioxide is likely.

Recent research has shown that the ozone-depleting chemicals, which we know have been significantly reduced in the last two decades, were also major contributors to global warming, so their reduction or elimination has had a very positive effect in countering global warming.

So, ozone and global warming: two different but interconnected problems, two different but interconnected causes, two (at least) different solutions.

CFLs and Other Bulbs - Real Energy Savings

2008-04-10T18:19:00.000-07:00

Compact Fluorescent and Other Bulbs…

We have heard a lot lately about compact fluorescent lamps (CFLs), even to the extent that municipalities and governments are considering banning the traditional incandescent bulbs in favour of CFLs. That seems to be rather heavy-handed and may not achieve the desired results, but action is required because lighting amounts to about 20% of our overall electricity consumption.

So let’s take a look at this trend and understand the benefits and drawbacks of these and other types of lighting.

The traditional light bulb, also called the incandescent bulb, is the original invention of Thomas Edison and Joseph Swan, dating from about 125 years ago. It works by passing an electric current through a thin wire filament, usually tungsten, inside an evacuated glass globe. The tungsten glows white-hot, and gives off light. As you can imagine, anything that glows white is pretty hot, and in fact an incandescent bulb only converts about 5% of the energy it consumes into light. The rest is given off as heat. We don’t always want heat along with our light, but up to now we get both like it or not.

The new popularity of compact fluorescent lamps (CFLs) owes a lot to two things: the great improvement in manufacturing leading to much lower cost, and the lower energy consumption. In fact, a CFL will last about 10,000 hrs, compared with about 1000 hrs. for an incandescent bulb, and it converts about 30% of its electrical energy into light. A CFL works by energising a gas inside the coiled glass tube, which causes a coating inside the tube to glow. As well, the new CFLs are brighter, more like natural light, and don’t flicker. Some heat is generated but far less than an incandescent bulb. Downsides are that they cannot be dimmed like an incandescent bulb and CFLs contain a small amount of mercury which is a concern at the time of disposal where the mercury may be released and contribute to air and water pollution.
Some manufacturers such as Philips, the Dutch electronics giant, and GE make very low mercury content CFLs. Safe disposal requires storing the bulbs unbroken until they can be processed. Consumers should seek disposal advice from local authorities, who need to prepare to receive these bulbs. Disposal methods include returning used CFLs to where they were purchased, so the store can recycle them correctly; or taking used CFLs to a recycling facility.
Proper disposal involves crushing the bulbs in a machine that uses specialized equipment and a mercury-absorbing filter to contain and treat the contaminated gases. Such machines are becoming more common along with CFLs. The crushed glass and metal is stored safely in drums, ready for shipping to recycling factories
Here is the real payoff… it is estimated that there are about 400 million incandescent light sockets in Canada. If 85% can be replaced with CFLs, we could save an estimated 15 million tons of carbon dioxide emissions and save nearly two billion dollars in electricity costs. That, readers, is serious conservation.

The real star players in the lighting Olympics are LEDs. LED stands for Light Emitting Diode. These put out an amazing amount of light for their power consumption, converting up to 70% of the electricity to light, and have a lifetime of more than 50,000 hrs. These numbers look pretty attractive, but they are still very expensive by comparison with incandescent and CFLs. You certainly get a lot of light for little electrical power. Work is progressing in making them cheaper, and in a range of “warm white” colours that people demand for home lighting. Philips has several programs underway to develop affordable and flexible LEDs. They are continuing to find many applications in automotive and aerospace, because of their small size, low power consumption and lack of heat generation. Almost daily we see new applications, such as tiny light gadgets for key chains, and convenient and bright flashlights.

If you can, do your part by converting your light bulbs to CFLs and help lower your electrical bill and your carbon dioxide emissions. It may be that the standard incandescent bulb is about to become the oil lamp of the twenty-first century, a useful gadget whose time has passed.

Lead in Drinking Water

2008-03-21T15:28:00.000-07:00

Lead in Drinking Water – A Discussion

We saw the news items recently that indicated that the Government of Ontario is concerned that the levels of lead in municipal water supplies are higher than the Provincial standards, and they have requested that about thirty municipalities across the province test the water in peoples’ homes.

There have been several articles in the Recorder and Times and numerous other papers regarding this, and I thought it would be appropriate to take a more detailed look at the issue and understand some of the background of the issue.

Lead has been around for a very long time, and has a history of use to man for millennia. In the twentieth century physicians began to realise that extensive exposure to lead caused neurological impairment (brain damage) to young children and was particularly dangerous to pregnant women. Human exposures through handling metallic lead such as fishing weights or working with stained glass are of no great concern. Our concerns are areas in which lead can be readily ingested, and this occurs in inhaling or breathing lead-containing dust, children chewing on lead-based paints, and of course, through food and drinking water. Since the elimination of lead additives to gasoline nearly twenty years ago, and the discontinuing of lead-based pigments in consumer paints, the first two are not significant contributors for most Canadians. This brings us to food and drinking water.

Lead levels in food are very strictly controlled and are generally at or below the limits of detection by modern analytical techniques. The levels in drinking water are set by the Ontario Government at 10 micrograms per litre. To put this in perspective, this represents about one-half of a BB pellet dissolved in a typical backyard swimming pool. The water entering the St. Lawrence is monitored at Wolfe Island, near Kingston, and the typical level seen there is 0.016 micrograms per litre, or about one five-hundredth of the allowable amount.

So if lead is so low coming into the Brockville water supply, where does it come from? Up until the early 1950s, lead pipes were in common use for water supply lines. They were easy to install, join, repair, bend, and the lead did not give a taste to the water. However, as the toxic effects of lead were understood, its use in drinking water pipes was discontinued and indeed Brockville has reviewed its use of lead and has determined that lead was not used for water distribution. However, there may be some homes primarily south of the railroad tracks where the line from the supply main to the house is still lead.

Now we get to the chemistry part… the inside of water supply lines typically becomes coated with scale, deposits of calcium and magnesium, and these deposits lessen the amount of lead which can dissolve in the water. Lead is less soluble in cold water than hot, so use cold for your cooking and drinking. As well, lead has a pH point (pH is a measure of acidity we will discuss in a future column) where it is minimally soluble in water, which is pH 7.6, and it happens that Brockville City water is pH 7.6 So what this all means is that we are lucky that the water chemistry works in our favour and we are not at great risk here.

Having said that, there are a couple of additional points to consider. Most homes built in the past fifty years or so used copper plumbing that was soldered together. Lead was a component of solder until the late 1980s. The amount of lead that dissolves from solder into water is thought to be very small, because of the low area exposed to the water, and we already learned that the chemistry is on our side.

If you live south of the tracks, and if you suspect that you have a lead connection, the recommended practice is to flush the toilet or run the shower before taking water that had been sitting overnight from the tap; this is something most of us would do anyway. Tests have been carried out in twenty houses in Brockville; all were within the Provincial standards and all but one were below 3 micrograms per litre.

The issue of lead in well water in Leeds-Grenville is more complicated, as our area includes limestone, Canadian Shield granite, and sedimentary soil, and each has its unique chemistry. The best information seems to be that there is very little lead in groundwater in Eastern Ontario. Go to the Health Unit website, www.healthunit.org/water/infosheet/aquainted.htm and www.healthunit.org/water/test/lead.htm to find out more about maintaining your well in good condition, and about lead testing and availability.

If you travel to Central and South America and bring back a highly-coloured piece of glazed pottery, use it for decoration only. Coloured glazes are often made from lead, cadmium and chromium, which make wonderful colours but are all very toxic. Many of our favourite beverages, such as fruit juices and wines, are very acidic (they have a low pH) and will extract the toxic metal from the glaze.

So use caution in your exposure to lead, run your taps, use cold water for cooking and drinking, and if you are really concerned, ask for a test.

Hydrogen as Automotive Fuel

2008-03-07T17:02:00.000-08:00

Many of us have been told, and have figured out that about the only fuel that doesn’t give off carbon dioxide as it burns is hydrogen. So it would make a great fuel for a motor vehicle, right? Well, as with everything, it is a good news/bad news story.

Hydrogen does indeed burn nicely, giving off water vapour and heat. Most current internal combustion engines can burn hydrogen with relatively minor modifications to the carburetor, and there would be no need for a catalytic converter. However, there are two big issues about hydrogen: how do you make it, and how do you store it?

Almost all industrial-scale hydrogen is currently made from natural gas, or methane. This process generates carbon dioxide as well as hydrogen. If we are thinking about hydrogen as a motor fuel, we will need more methane than is currently available, and we will generate a lot of carbon dioxide. So… how else can you make hydrogen? You can pass electricity through water, and you get hydrogen and oxygen, lots of both. But you had better have your own generating plant, because you will need a lot of really cheap electricity. You don’t really want to burn anything to make your electricity, such as coal, oil, or natural gas, as you will make more carbon dioxide, so you are stuck with hydro and nuclear, our current favourites, or perhaps wind, solar, or tidal electricity, none of which gives enough power, at current generation efficiencies, to do the job. Fusion power is several years in the future at least. Seeing as we have dammed most of the rivers that are suitable, we are looking at nuclear – generated electricity as the most practical option. I know nuclear – generated electricity is like a red flag to a bull to many members of our community, but let cool heads prevail and let’s discuss it in reasonable terms (in another column).

After you have made your hydrogen you need to be able to carry enough in your vehicle to give about 400 – 500 km. driving. The current methods include a large high pressure (200 to 350 atmospheres, an atmosphere is about 15 psi) tank, weighing up to hundreds of kilograms, or a lower pressure tank (10 to 100 atmospheres) containing metal hydrides, which store hydrogen like a sponge, and give it up with gentle heating. GM, Toyota and Honda are all researching various promising hydride technologies. Both of these storage systems are going to fill the trunk of a standard car or mini-van. Another method of hydrogen storage is as a cryogenic (very very cold) liquid. This gives a greater energy density, but at the expense of having to cool and compress the hydrogen to begin with, then having to insulate the tank, which would be at about -250°C. Another issue would be filling your tank, not simply a matter of sticking a nozzle in a trapdoor in your rear fender as we are accustomed to doing. As technologies emerge, the infrastructure will need to be put in place to make hydrogen motor fuel available in the right form, requiring huge investments by supplying companies. Governor Schwarzenegger of California and Premier Campbell of British Columbia have just committed to a “hydrogen highway” from Los Angeles to Vancouver, with hydrogen fuel available along the Pacific Coast. There is also the huge psychological obstacle I’ll call the Hindenburg Factor – remember the German dirigible which crashed and burned spectacularly in 1937 (or the movie of the same name in 1975) and many people will say “No way!”. Having said that, the hydrogen industry as it exists today has an excellent safety record.

Despite these rather daunting technical challenges, several automobile manufacturers are going ahead with hydrogen-fuelled vehicles. BMW plans to introduce the Hydrogen 7, which will incorporate an internal combustion engine capable of running on gasoline for 500 km., or hydrogen for 200 km. Ford is marketing the “Edge”, a crossover SUV that is powered by plug-in hybrid fuel cell system that runs on hydrogen in a high pressure tank and goes 325 km between fill-ups. Not sure where they will fill it up in Brockville for a while yet.

One of the more promising areas where hydrogen-fuelled vehicles will be the right choice is urban transit. Buses work in a clearly-defined radius, they return to a central location where specialised fuelling can be set up, they work in cities where air quality can be a serious issue, and they are large enough to have room for special storage tanks.

So where does all this leave us? It is easy to say that hydrogen is the fuel of the future, and is pollution-free, and indeed it looks great on the surface. But as we can see, there are many issues and technological hurdles to be overcome before we can bid the gasoline and diesel internal combustion engines goodbye.

Ethanol as Automotive Fuel

2008-02-22T12:40:00.001-08:00

Remember in the last column we spoke about ethanol and how it is made. Today I would like to explore the role of ethanol in automotive fuel.

First, let’s take a quick look at gasoline. Gasoline, as with most fuels, is a hydrocarbon. That means that its molecules are made up of carbon atoms and hydrogen atoms, with the carbon atoms forming either a straight chain or a branched chain. Hydrocarbons make good fuels because they burn easily in the presence of air. You are already familiar with natural gas, a one-carbon hydrocarbon, with a simple formula of CH4, and called methane. Propane, the common barbecue fuel, is three carbons long, so its formula is C3H8. Methane is a gas at room temperature, and propane is a gas but becomes liquid when compressed. By the time we get to 6 carbons atoms, the hydrocarbons are liquids, and become solids above about 14 carbons… wax! So, gasoline is typically about 8 carbons. I say typically because gasoline is not a single compound, but a range of very similar chemical compounds that have a specific boiling point, or that boils over a narrow temperature range.

So, when gasoline and air are introduced into an internal combustion engine, compressed and ignited, the mixture burns very rapidly, and the resulting displacement of the piston in the cylinder turns the crankshaft and thus the wheels. However, we do not live in a perfect world. There is never quite enough air mixed with the fuel to burn everything, so as well as the carbon dioxide, we get carbon monoxide and some chemical fragments of the gasoline molecules that form soot and other compounds. If we add something to the gasoline that has oxygen in it, such as ethanol, (remember the formula for ethanol is C2H5OH) we can achieve a better and more complete combustion. Nevertheless we are still stuck with carbon monoxide and dioxide, serious greenhouse gases.

There is a downside, of course. The oxygen in the ethanol molecule means that weight for weight it doesn’t have the bang that gasoline has, so there is a fuel mileage penalty, estimated at up to 10%, but a cleaner exhaust. The trick is to add enough ethanol that the exhaust quality improves, but not too much to upset the fuel injectors and the internals of the engine management system. If you look at most pumps around Brockville, you will see a sticker saying “may contain up to 10% ethanol”. This level can be tolerated by most modern vehicles without modification. If we want to run higher levels of ethanol, we have to make sure our vehicle is equipped to handle the additional ethanol.

There is a current oxygen-containing additive called MTBE (we’ll skip the formula for now) which serves the purpose of providing extra oxygen, but there are issues around its safety and it is made from crude oil, whereas we know where we can get ethanol.

Some of you may be familiar with the situation in Brazil. There is little natural petroleum in Brazil, but a huge quantity of sugarcane and low cost labour. Therefore ethanol derived from sugarcane forms a large part of the Brazilian motor fuel supply, and all vehicles sold in Brazil are designed to use this fuel. As well, there would be operational problems using pure ethanol as a fuel in our winter conditions, something the Brazilians do not have to consider.

So, using ethanol as a fuel additive or substitute will have a beneficial effect upon emissions, and will reduce our reliance on crude oil, but it is not the magic cure that some have promised. The latest estimates, and they are only estimates, indicate that the substitution of a major portion of our gasoline with ethanol may result in a reduction of the transportation component of greenhouse gases of up to 25 – 40%. Another issue is that a major new market for ethanol will benefit farmers but may drive up the cost of chicken, beef, and other foods for which the corn from which ethanol is made is a food source or raw material.

There is also controversy around the overall energy balance of ethanol – that is, how much energy in diesel fuel, fertilisers, etc. does it take to make a kilogram of ethanol from corn, vs. how much energy it gives to the gasoline. I have seen estimates from 50% to 150%. It is easy to see how anyone with a vested interest can make the data look favourable for their cause.

The only fuel that can play a really significant role in reducing greenhouse gases is hydrogen, and we will look at that in a future column.

Science Matters... Ethanol

2008-02-13T07:09:00.001-08:00

There are many complicated issues facing the public these days, ranging from waste disposal, recycling, air and water emissions, energy generation and consumption, transportation, and many others. These issues have at their core some elements of science, whether it is chemistry, physics, biology, engineering, statistics, or some combination of these. With your help, I would like to explore some of these issues and examine the science in more detail and together we can understand what is going on, what we are being told, whether it makes scientific sense, and perhaps make a slightly better judgement about the issue. I hope to use my contacts and experience in the scientific community to assist you, the readers, in understanding these issues. I welcome your input.

Our area is about to benefit from the construction and operation of an ethanol plant, and I thought it might be appropriate to look at some of the chemistry of ethanol and try to understand what it is, what it does (as a fuel additive) and what are the pros and cons.

Most of us are familiar with ethanol in the form of alcoholic beverages: wine, beer and distilled spirits. It is suggested that the manufacture of alcoholic beverages counts as the first chemical industry, dating back thousands of years. The ethanol we drink is diluted, with water, fruit extracts and flavourings, to about 5% in beer, about 12% in wine, and about 40% in distilled spirits.

Ethanol, or ethyl alcohol as it is known in chemistry, is a clear colourless flammable liquid, completely miscible (mixes with) water in all proportions. It is the second in a chain of alcohols, because of the two carbon atoms, the first being methanol. The chemical formula is C2H5OH, with the OH group giving the characteristics of an alcohol.

The first and still most important way of making ethanol is via fermentation of sugar or starch. Grapes were among the first fruits to be fermented because grapes are naturally sweet, the enzyme that produces ethanol is found on grape skins, and ethanol production is very simple, and takes place at room temperature, especially if your room is in the Mediterranean basin. Many fruits, vegetables and grains have been fermented in pretty much the same way to arrive at ethanol with many flavours, but the basic chemistry remains the same.

When you are making beer and wine, you allow the fermentation to proceed to a specific point then you stop it chemically, filter or decant your product, and depending on your patience, let it mellow a little before drinking. Because the enzymes that do the work are killed off when the ethanol concentration is above about 15%, no wine or beer is naturally stronger than this.

If you are making spirits (such as rum, rye, vodka etc.) or industrial ethanol, you must distil your mixture. Because ethanol boils at a lower temperature than water, if the fermentation mixture is heated above the boiling point of ethanol (78°C) but below 100°C the ethanol will boil and can be captured by cooling the vapour, giving pure ethanol.

So, our plant in Johnstown will be taking corn, the same corn we feed to cattle and other animals, and fermenting it, then distilling it on a large scale.

Here is what is happening, shown another way:

C6H12O6 --> 2 CO2 + 2 C2H5OH
glucose carbon dioxide ethanol

This is how we show a reaction in chemistry, and it isn’t really complicated. Glucose is the simplest sugar. What is really interesting is that for every kilogram of ethanol produced, we get, free and for nothing, 0.95 kilograms of carbon dioxide. So far, no-one has said anything about the carbon dioxide by-product of fermentation.

Another issue with ethanol is this: Right now all the fermentation technology relies on acting on the fruit or the seed grain portion of the plant material, because that is where the sugar or starch is concentrated. As anyone who has shucked corn knows, there is a pile of the corn plant that is wasted. If we can figure our how to convert that waste material, mostly cellulose, into ethanol, we will have some real progress. Thankfully, an Ottawa company called IOGEN has developed a process to do exactly that, and when it is commercialised (it is currently in the pilot-plant stage) then ethanol may become a significant player in the alternate fuel debate.

As we currently stand, the energy balance, that is, the amount of energy you have to put into making ethanol vs. the amount of energy you get out is subject to considerable controversy. We will take a look at this later.

Now, ethanol may have significant benefits with respect to automotive emissions, and reducing our reliance on fossil fuels, but as you can see it certainly doesn’t get us off the hook with respect to carbon dioxide, one of the main greenhouse gases.

Next week we will take a look at what ethanol does when it is mixed with gasoline and diesel fuel.