Having a Bad Air Day?

Air pollution is a key contributing factor to the increasing prevalence of asthma, chronic bronchitis, lung cancer, and a host of other diseases. Learn about common air pollutants, and find out how to avoid them and breathe easier.

How Bad is it Really?

A U.S. study demonstrates how harmful air pollution can be. It found that children with asthma were 40 per cent more likely to suffer asthma attacks on high-pollution summer days than on days with average pollution levels. The Ontario Medical Association estimates that air pollution costs the province of Ontario health care system more than one billion dollars annually in “hospital admissions, emergency room visits, and absenteeism.”

Carbon Monoxide

Automobile emissions are the main source of carbon monoxide (CO) in the air. Invisible and odorless, CO invades your red blood cells and displaces life-giving oxygen. Consequently, less oxygen is carried to the cells in your body. People who suffer congestive heart failure (a life-threatening chronic condition in which the heart cannot pump out all the blood that enters its chambers) may be extremely vulnerable to the effects of CO. Studies show that even permissible levels of CO could intensify heart-failure symptoms enough to require hospitalization, and that high exposure to CO for even a short period can lower the amount of exertion it takes to induce chest pain (angina) in people with coronary artery disease.

What you can do: Regular car maintenance can help reduce your exposure. Because CO can escape from gasket leaks, holes in the muffler, or holes in the pipes, it’s critical to get your car’s combustion and exhaust systems checked out regularly. Even normal CO emissions can make you sick if your car is standing still with its motor running and there is no wind.

If you work on your car in your garage, make sure the garage door is completely open and that exhaust fumes from the garage do not enter your house. Also, keep vehicle windows closed in tunnels and enclosed parking garages. If you’re a smoker, quit—tobacco smoke contains high CO levels.


Ground-level ozone (or smog) forms when sunlight reacts with chemicals emitted by cars and various commercial and industrial sources. Ozone is a powerful respiratory irritant. In high concentrations, it can severely limit your ability to take a deep breath, causing coughing, throat irritation, and discomfort on breathing. There is also evidence that ozone can lower resistance to respiratory disease (such as pneumonia), damage lung tissue, and aggravate chronic lung diseases (such as asthma or bronchitis). The severity of these effects increases with the concentration of ozone in the air, the length of exposure, and the amount inhaled.

When you exercise, you breathe faster. In high-ozone environments, this means that more ozone gets into your airways and lungs. Even healthy people may suffer breathing difficulties if they exercise outdoors when there’s an ozone alert. Ozone is at its worst on hot, stagnant summer afternoons in areas with large volumes of motor vehicle traffic.

The harmful ozone in the lower atmosphere (troposphere) should not be confused with the protective layer of ozone in the upper atmosphere (stratosphere), which screens out harmful ultraviolet rays.

What you can do: If possible, stay indoors in a cool, well-ventilated place on days when the air quality index is unhealthy. Children tend to be more sensitive to ozone pollution than adults because they breathe faster. During peak smog months (May to September), plan “must-be-outside” activities for early in the morning, when air pollution is lowest.

Particulate Matter

A wide range of man-made and natural pollutants—pollen, road dust, diesel soot, and wood smoke to name a few—are suspended as particles in the air. These particles are a mixture of visible and microscopic solids and liquid droplets known as aerosols, which are easily inhaled.

The danger is significant, according to a seven-year study from the Harvard School of Public health. The study, which followed 552,138 people in 151 U.S. cities, found that residents of areas with the highest concentration of particulates had a 16 per cent higher risk of death from all causes than those who lived in the least polluted areas. Death rates from heart and lung diseases were particularly high in polluted locales. Interestingly, the findings were consistent for smokers and nonsmokers alike. Even smokers who lived in unpolluted areas were less likely to die.

What you can do: You can’t choose the air you breathe, but you can choose cleaner and more efficient energy sources for home heating and cooling, transportation, and appliances. Carefully maintaining your automobile and carpooling whenever possible are also good ideas. Finally, limiting the use of fireplaces and wood-burning stoves will make your indoor air safer.

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