Scientists in the Meteorological Service of Canada (MSC) at Environment Canada study the chemistry and physics of the atmosphere. This research is focused on short-term events (weather), longer-term atmospheric conditions (climate) and air quality issues, such as acid rain, stratospheric ozone depletion and the resulting increase in ultraviolet radiation, ground-level ozone (smog), hazardous air pollutants and particulate matter.

Government scientists frequently work with researchers in universities and other federal and provincial departments, as well as with experts in the private sector, on atmospheric issues of mutual interest. Where human or ecosystem health is affected by atmospheric conditions, cooperative work is also carried out with scientists in these fields.

In addition to carrying out laboratory and field experiments, scientists monitor the quality of air and precipitation across Canada on an ongoing basis. These measurements help pinpoint the location of pollutant sources and link them with impacts. The analysis and assessment of the monitoring data helps to determine trends and predict future conditions, and serves as the basis for taking action—such as policy making and efforts to warn and inform the public.

The MSC carries out atmospheric monitoring in the areas of acid rain, atmospheric mercury, toxic air pollutants, radiation (ultraviolet), stratospheric ozone, smog and particulate matter. Monitoring sites are located across the country and many different measurements are collected at each. MSC’s sister service, the Environmental Protection Service, operates the National Air Pollution Surveillance Network (NAPS) at approximately 152 sites as a cooperative venture with provincial, territorial and municipal agencies to monitor and assess the quality of air that Canadians breathe.

The MSC also uses air quality data to assist in the development and verification of mathematical models that simulate the atmospheric transport, diffusion and chemistry of air pollutants. These models are useful for synthesizing knowledge about atmospheric processes, predicting air quality, helping to formulate, review and revise policy decisions by assessing the benefits of different pollution control strategies, and increasing understanding of environmental problems.

The MSC has developed the Canadian Hemispheric and Regional Ozone and NO_x System (CHRONOS)—the first modelling system in North America used for predicting ground-level ozone concentrations associated with photochemical smog episodes. Future plans include the explicit prediction of particulate matter in the atmosphere and the implementation of models capable of predicting air quality on an urban scale.

An important use of atmospheric models, such as CHRONOS, is to provide information for use in forecasts and advisories so that Canadians can take steps to minimize health risks associated with air pollution.

MSC has worked with provincial and municipal agencies to provide air quality and smog advisories across Canada since 1993, when smog advisory programs were first introduced in Saint John, Montréal, Toronto and Vancouver. Initially, these programs provided notification only when a smog episode had already begun. Now, they are often provided a day in advance.

In 1997, MSC, the Province of New Brunswick, and health organizations joined forces to launch the first daily Canadian Smog Forecast program in Saint John. The program, which expanded this year to include all of New Brunswick, delivers a 48-hour forecast of ground-level ozone twice daily during smog season, and once daily during the rest of the year.

The MSC also provides meteorological information and other assistance to Ontario’s new Smog Alert program, which covers the southern part of the province and provides daily forecasts of air quality for the coming three days.

Early this year, Environment Canada committed an initial investment of $1 million to expand its Air Quality Prediction Program across Canada within the next year. This summer, efforts are focused on issuing daily air quality forecasts in the areas most affected by smog, particularly in the maritime provinces.

MSC also produces a venting index forecast for coastal and interior areas of British Columbia. The index provides air flow predictions that help foresters, farmers, and landholders determine when controlled burns can be carried out without affecting visibility in the vicinity of airports, highways and towns.

Science assessments feed the decision-making process and connect the atmospheric science and policy communities. Conducted by scientific working groups made up of representatives from Environment Canada, other government departments and agencies, industry associations, institutes and environmental organizations, science assessments represent the current state of science on a subject, note gaps in scientific knowledge and in existing research capability, recommend directions for future research, and guide policy.

Formal science assessments are conducted on a wide range of environmental subjects, including air quality issues such as acid rain, climate change, ozone, and particulate matter and increasingly on individual toxic substances that have an atmospheric component to their life cycles. The results of these assessments are provided to policy makers, science audiences, the general public and other stakeholders in the form of reports, briefing notes, presentations, seminars and workshops. Frequently, science assessments are linked to effects research and to risk analyses, all of which help policy-makers design, review and revise policies and other tools for improving our air quality.