National Air Pollution Surveillance Network (NAPS)


From 1961 to present


The National Air Pollution Surveillance (NAPS) Network was established in 1969 as a joint project of the federal and provincial governments. The accumulation of accurate air quality data over the years thus provides good long-term trend information to evaluate the progress of air pollution abatement measures and to direct abatement action where needed.

The NAPS Network has produced one of the largest and more geographically diverse databases of high quality atmospheric particle measurements in the world. A maximum of thirteen and a minimum of two years of data are available for 37 Canadian locations. Daily summertime measurements were collected in 1992 and 1993 at up to six locations. There are total of 21 active sites. The network started to investigate the relationship among TSP, PM10, PM2.5, SO4= and other inorganic constituents of atmospheric particulate matter at a variety of urban and rural Canadian locations in 1992. This network is unique with these simultaneous measurements over a number of years. These analyses provide information useful to air pollution, health effect studies and to the regulatory assessment of the particle issue.

Dichotomous sampling sites (as of January 1997) have been operated at 28 different locations. Most of the sites have a high volume sampler for total suspended particulates (TSP) collocated with the dichotomous sampler. Some of the sites have been relocated and are no longer active. Since July 1995, 16 sites have been in operation.

Size selective inlets sites have been operated in 14 locations. Five of these sites are colocated with dichotomous sampling sites. Currently, there are ten active sites with size selective inlet high volume samplers.


To monitor and assess the quality of the ambient air in the urban regions of Canada continuously.

Collection Information:

The nominal sampling period is 24 hours every 6 days. Sampling starts at 00hrs or 8000hrs depending on the sites.

The mass on the filter samples is first measured with Mettler M3 or MT5 microbalance. Then the filter samples are analyzed for trace elements using energy dispersive X-ray fluorescence spectrometer. Finally, each filter is extracted in water (isopropanol wetting agent) and analyzed by ion chromatography for major ions.


Tom Dann
Environment Canada
3439 River Road, Ottawa, Ontario K1A 0H3
Tel: 613-991-9459
Fax: 613-998-4032
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