National Air Pollution Surveillance (NAPS) Monitoring Results

Canada’s National Air Pollution Surveillance network data is validated using automated and manual procedures. Data from the network agencies is converted to a compatible format and then entered into the NAPS database. Although the data has been validated by an analyst from the originating agency, the values are also submitted to tests outlined by the U.S. Environmental Protection Agency. When data is flagged automatically or manually for another look, the originating agency must confirm the data before it’s stored in the NAPS database.

Air monitoring data indicate pollution levels at sampling sites only and may not necessarily represent community-wide air quality. Community-wide comparisons can only be made by using data from all available sampling stations in a region, and interpreting them on the basis of specific monitoring site characteristics.

Air Pollutants Measurement

Air quality data for criteria air pollutants such as sulphur dioxide (SO2), carbon monoxide (CO), nitrogen dioxide (NO2), ozone (O3) and particulate matter (PM) are measured at approximately 300 stations in 200 communities in the ten provinces and three territories. The actual number of stations with data may vary annually depending on the completeness criteria. For smog assessments (ground-level ozone), data for nitric oxide, nitrogen oxides and volatile organic compounds (VOCs) are also collected. Measurements of PM10 and PM2.5 (suspended particles with aerodynamic diameters less than 10 micro meters and less than 2.5 micro meters) have been made at Canadian sites since 1984. Sample filters are analyzed for 50 elements (including toxic metals such as arsenic, lead and mercury) 14 inorganic and organic anions (negatively charged ions) and 11 inorganic cations (positively charged ions).

In cooperation with provincial and municipal environmental agencies, the National Air Pollution Surveillance (NAPS) Network collects, compiles and analyzes data on more than 300 trace contaminants in ambient air. Sampling is carried out at approximately 40 urban, suburban and rural locations in the country. Categories of species sampled include fine particulates and metals, volatile organics such as benzene and formaldehyde as well as semi volatile organic compounds such as polycyclic aromatic hydrocarbons, and polychlorinated dibenzo-p-dioxins. For many species, sampling has been carried out at the same sites for more than 15 years. In 2011, sampling for polychlorinated dibenzo-p-dioxins, hexachlorobenzene, octachlorostyrene, pentacholorophenol was discontinued at NAPS sampling stations.

In 1996, Environment Canada's compound list was expanded to include a number of additional species that are targeted in the Canada-Ontario Agreement respecting the Great Lakes Basin Ecosystem. These include Tier I (targeted for virtual elimination) and Tier II (persistent, bio-accumulative and toxic substances of concern) substances. Three new sites were added in rural Ontario and a more frequent sampling schedule was employed. However, in 2011, the monitoring and data analysis was discontinued. Historical data for these additional chemical groups analyzed (Dioxin-like Poly chorinated byphenyls (PCB)s, Octochlorostyrene (OC), Pentachlorophenol (PCP), and Hexachlorobenzene (HCB)) is available for download.

Data may be downloaded