Environmental Quality Branch

VEHICLE EMISSIONS

No Room To Breathe: Photochemical Smog and Ground-Level Ozone

Last Updated: August 1992

Introduction

You can see it as you drive into the Lower Fraser Valley on a warm summer day — a brownish haze that hangs over the city, marring the beauty of blue sky and mountains.

It's called photochemical smog and it's not just unsightly — it's unhealthy. Nor is Greater Vancouver the only area that suffers from smog. In fact, this serious form of air pollution occurs in many major urban and industrial areas in Canada.

Each one of us can help bring the fresh air back to our land. That's because we each contribute to creating it in the first place — the exhaust from our automobiles is the number one cause.

This brochure describes what smog is, how it affects our health and the environment, and most important — how YOU can become part of the solution.

Photochemical Smog

Photochemical smog occurs in the lower portion of our atmosphere, known as the troposphere. Its main unhealthy ingredient is "ground-level ozone."

Ozone is formed by the reaction of volatile organic compounds (VOCs) and nitrogen oxides (NOX) in the presence of sunlight and warm temperatures. A stagnant air mass — the result of high atmospheric pressure and light winds — keeps the pollution from being dispersed. The ideal conditions for ozone buildup occur from late spring to early fall in most Canadian cities.

It should be noted that VOCs, NOX and ozone occur naturally in the lower atmosphere, too. However, human activities — fossil fuel use, in particular — have greatly increased the amounts.

VOCs (also called hydrocarbons) are the most important constituents of oil and natural gas. The major man-made source of VOC emissions is motor vehicles. Evaporation of gasoline, solvents, oil-based paints, and hydrocarbons from the petrochemical industry are also significant sources.

Like VOCs, NOX are mainly produced by oil and gas, but in this case it's burning the fuel that does it. The exhaust from fossil fuel combustion in our motor vehicles is the primary source, followed by fuel burning in homes, businesses, factories and power plants.

Ironically, although we humans are causing too much ozone in the troposphere, we're triggering ozone destruction in the upper reaches of our atmosphere - the stratosphere. Ozone depletion in the stratosphere is allowing more and more of the sun's potentially damaging ultraviolet radiation to reach the earth's surface. Its cause is the discharge of ozone-destroying chemicals such as chlorofluorocarbons (CFCs) and halons.

There is, unfortunately, no way to siphon the over-abundance of ground-level ozone in the troposphere up to the stratosphere, to fill in the depleted ozone layer. What we have to do is get at the root of the problem — human beings and their activities. If we want to "breathe easy," we have to clean up our own act.

More Than an Urban Problem

Ground-level ozone collects over the cities that produce large amounts of VOCs and NOX. But it can also migrate up to several hundred kilometres downwind. Topography (such as valleys) and meteorological conditions (such as clear skies and stagnant air) promote ozone buildup. Sometimes the smog is most intense far from its source.

The Lower Fraser Valley has one of the worst smog problems in Canada, surpassed only by the urban belt extending from Windsor to Quebec City. Strange as it may seem, though, downtown Vancouver does not experience the highest ozone levels in the area. The middle and eastern portions of the Lower Fraser Valley bear the brunt.

The reason is that it takes time for the sun-driven chemical reaction to transform the NOX and VOCs emitted from Greater Vancouver into ground-level ozone. While sea breezes blow eastward, this process of transformation takes place and ozone is gradually produced. The mountains then trap the pollution in the eastern part of the valley. Hence the greatest concentration of ozone often occurs in the vicinity of Coquitlam and Port Moody.

What about other cities in British Columbia? Topography and summer weather conditions will predispose many of our urban areas to smog, if the population and automobile emissions become large enough.

Early indications from the Okanagan and Greater Victoria (the places most likely to experience smog, at present) suggest that ozone is not yet a significant issue. However, the growth rates in both locales and the general increase in motor vehicle use make it important to take preventive action now, before smog can become a problem. The same is true for cities across British Columbia. Regional transportation planning is especially crucial.

How Does Smog Affect Us?

Human Health

Low concentrations of ground-level ozone can irritate the eyes, nose and throat. As smog increases, it can trigger more serious health problems, including:

• asthma, bronchitis, coughing and chest pain;
• increased susceptibility to respiratory infections; and
• decreased lung function and physical performance.
  

Prolonged exposure can eventually damage lung tissue, cause premature aging of the lungs and contribute to chronic lung disease. Children, the elderly and people with impaired lung function are considered to be most at risk.

Vegetation and Materials

Sensitive crops, trees and other vegetation are harmed at lower ozone concentrations than is human health. Ground-level ozone can damage leaves, and reduce growth, productivity and reproduction. It can cause vulnerability to insects and disease, and even death.

When ozone levels are fairly high over a long period, agricultural crops can suffer significant harm. In the Lower Fraser Valley, for example, the agricultural production that could be lost each year to smog damage is estimated to be worth several million dollars.

Smog can also accelerate the deterioration of rubber, fibres, plastics, paints and dyes.

The Enhanced Greenhouse Effect and Acid Rain

The pollutants we spew into our atmosphere are implicated in more than one environmental problem. Ozone, for example, is not only a major component of smog; it also contributes to the enhanced greenhouse effect, which is predicted to lead to global climate change. Similarly, NOX — one of the building blocks of ground-level ozone — plays a major role in creating acid rain.

Putting the Lid on Smog

It's tempting to retreat into apathy to escape the army of environmental ills confronting us. But that will just make the problem worse - for us, our children, and the children of tomorrow. Local smog problems alone won't destroy life as we know it. However, in combination with other pollutants they may inflict a serious wound.

This is a time of supreme challenge for humanity. Never before have we had the power to destroy the planet's delicately balanced ecosystem. We also have the power to save it. But we need to act now. All of us.

Caring for the environment begins at home and with each individual. Opting for a more environmentally friendly lifestyle will take a little effort but think of the reward: fresh, clean air for present and future British Columbians!

Reducing vehicle emissions is the key to improving air quality, since automobiles are the largest single source of VOCs and NOX. (They also emit a variety of other contaminants, including harmful particulates and carbon monoxide.)

In the Lower Fraser Valley, 75% of local air pollution (containing the chemicals which lead to ozone formation) is caused by motor vehicles. Rush-hour commuters in private cars are the major culprits in producing vehicle emissions. Most of those cars hold only one person. What a waste!

Even if each of us leaves our car at home just once a week - opting instead for the bus, bicycle or carpool - the reduction in emissions will be substantial. Our pocketbook will benefit, too!

Cutting down on our smog-producing activities is especially important on days when the potential for smog formation is high — such as during hot sunny and calm weather.

To find out more on how YOU can help clear the air, read on:

Conserving Energy is the Key!

• Use public transit or become part of a carpool. Better yet, ride your bike or use your two feet!
• When you have to drive, save energy! Combine errands, and don't let your car sit with its motor running longer than 30 seconds. Make sure your vehicle's engine is in top shape, with low emissions.
• Looking for a new car? Go for a smaller, fuel-efficient model. It will save you money and be easier on the environment, at the same time.
• When starting your car on a cold day, remember to move off slowly after 10 seconds of warmup. This is good for the atmosphere, the car and your finances.
• Slow down when you drive. Not only will you avoid a speeding ticket, you'll also use less gas and thereby produce less pollution.
• Support urban planning that lowers automobile use — such as increased bicycle use, better public transit systems and vehicle-free areas.
• Prevent gas leaks by resisting the temptation to overfill your gas tank. Gas spillage emits VOCs.
• Use radial tires to cut down on tire drag and save gas. By inflating your tires to the manufacturer's recommended pressure you'll save up to 10% on fuel consumption — and the air will be better for it.
• Convert to cleaner, more efficient fuels. Natural gas is an interim solution. Though it's more efficient than oil and creates fewer emissions, gas is still a fossil fuel and releases large quantities of carbon dioxide and other pollutants. Hydroelectricity is preferable to both, and solar energy is another environmentally friendly option.
• Use garden tools that don't run on gasoline. In addition, avoid using lighter fluid to start your barbecue. It releases VOCs — an electric and barbecue starter doesn't.
• Paint with water-based (latex) paint rather than the oil-based variety. The latter contains three to five times more toxic solvents than water-based paint.
• Buy products with less packaging. It takes a lot of energy to make packaging, and VOCs are generated during the printing process.
• Let your personal commitment to a healthy environment reach out into your society. Tell your friends and family why it's so important to reduce emissions — and explain how they can help. Your example and gentle persuasion can really count.
• Support government action to stop air pollution. And contact your elected representatives to express your concerns and ideas about getting rid of smog.

For More Information:

Environmental Quality Branch
Ministry of Environment
Government of British Columbia
PO Box 9341
Stn Prov Govt
Victoria, British Columbia
Canada V8W 9M1
http://www.env.gov.bc.ca/air