Smog

Meteorological conditions greatly influence smog.ZoomZoom
© RSQA

Article published in the Courrier Laval July 23, 2006.

These days, when the weather is unbearably hot and there is no wind, smog is out there waiting. This harmful fog, full of pollutants, must be watched very carefully. How can we contribute to reducing smog? What should we do when there is smog? Here are some basic information and advice, which should help us to improve air quality.

Smog gets its name from a contraction of the words smoke and fog, but the phenomenon comes from an accumulation of fine particles and ozone at ground level. "In addition to vehicles and industry, two-cycle lawnmowers and gasoline powered leaf blowers are also sources of pollution." confides Tom Kosatsky, epidemiologist for the Direction de santé publique (DSP) of Montreal. Incomplete combustion of gasoline produces fine particles, nitrogen oxides, and volatile organic compounds, the two precursors of ozone. It is these particles, from local or distant sources, and the ozone naturally produced during hot sunny days that are the source of summer smog. The effects on human health are severe, particularly on people suffering from chronic pulmonary diseases, asthma, or heart problems. "Children living in more polluted regions are more at risk of experiencing a decrease in their pulmonary function than children living in cities with less smog" says Tom Kosatsky. An air quality index (AQI) has been developed. Based on acceptable norms for various pollutants, it allows us to quantify air quality. Appearance of smog can even be predicted 24 hours in advance so that warnings can be issued. A decrease in outdoor physical activity is then recommended, especially for the more vulnerable, because physical efforts increase pulmonary and cardiac activity.

Last year, there were 66 days during the year where the IQA was surpassed at at least one sampling station on the Island of Montreal, but these 66 days were not all concentrated during the summer. "On a yearly basis, for the province of Quebec, wood heating contributes 47% of fine particles from human sources, industry 33%, and transportation 17%" says Norman King, from Montreal’s DSP. These particles contribute greatly to winter smog.

The implementation of standards has allowed us to regulate pollutant emissions by modifying processes or by capturing them at their source, but our individual choices can also have an impact. By opting for public transport or active transportation, or by buying vehicles that pollute less, we can decrease the emission of pollutants and of the greenhouse gases responsible for global warming. Replacing gasoline powered leaf blowers and lawnmowers by electric models also contributes to improving air quality. During winter, a decrease in wood heating will have a marked effect on air quality. Therefore, let us not forget to revise our practices in all seasons!