Air Quality Standards : proposed decisions on particulate matter and ozone  Particulate matter in air  Current Canadian Particulate Matter in Air Objectives  Current Canadian Air Quality  Particulate Matter in Air: The Science   Current Canadian Particulate Matter in Air Objectives The existing Canadian government ambient air quality objectives for particulate matter in air are in transition. National ambient air quality objectives still exist for Total Suspended Particulate (TSP). They do not, however, reflect the current scientific understanding of the health effects of particulates or the priority that Canadian governments are placing on this public health issue. Already, some provinces have put provincial standards for PM 10 and PM2.5 in place that reflect more realistic levels based on health effects. TABLE 2: Ambient Particulate Matter Standards and Objectives in Canada and the U.S.

Permissible Pollutant Concentrations (micrograms per cubic metre (µg/m³))

Pollutant

Averaging Time

Canadian Objectives

Some Provincial Standards

U.S. Standards Proposals

Acceptable Level

Newfoundland

British Columbia

Total  Suspended  particulate (TSP)*

24 hour

120*

120

120

Annual

70*

70

PM10

24 hour

50

50

150

Annual

50

PM2.5

24 hour

25

50

Annual

15

   Current Canadian Air Quality In 1993, there were 36 monitoring sites across Canada that measured particulate concentrations. As with the United States, Canadian cities tend to be well above the background estimates. Concentrations of particulates in the ambient air of major cities across the country are illustrated in the following two figures. The levels for proposed annual and 24-hour U.S. NAAQS are indicated by solid lines at 50 µg/m³ and 150 µg/m³ for PM10 and 15 µg/m³ and 50 µg/m³ for PM2.5, respectively.

Evidence from nearly 20 years of research in acidic deposition indicates that the U.S. is a significant contributor to Canadian particulate concentrations in regions experiencing transboundary air pollution. Most Canadian cities have daily concentrations that are below the proposed 24-hour U.S. NAAQS for both PM10 and PM2.5. However, some sites have a significant portion, sometimes greater than 50% for PM2.5, of daily events above the proposed annual U.S. NAAQS levels. This is an indication of the importance to Canada of U.S. efforts to reduce particulate concentrations.   Particulate Matter in Air: The Science The scientific evidence of the effects of ambient particulate matter on human health is very comprehensive. On the basis of this evidence, Canadian national ambient air quality objectives are being developed by the Working Group on Air Quality Objectives and Guidelines (WGAQOG), which reports to the Federal/Provincial Advisory Committee (FPAC) under the Canadian Environmental Protection Act (CEPA). The scientific assessment process underway within the WGAQOG is nearing completion and the peer reviewed documentation and a recommendation regarding new "levels" for particulate matter with less than a diameter of 10 mm and 2.5 mm are expected within the coming weeks. The process Canada is undertaking to assess the effects of particulate matter is similar to that being completed by the U.S. EPA to define NAAQS proposals. The Canadian science assessment has been based on the same health evidence available and used by the EPA as well as some recent Canadian work.  Although not yet public, evidence in the Canadian assessment clearly supports the concern that U.S. EPA NAAQS proposals for particulate matter remain, if implemented, at levels that are in the adverse effects range. The following conclusions can be drawn, even at this preliminary stage, from Canada's assessment of the scientific evidence. All the evidence for all of the end points that have been considered - mortality, hospitalizations, chronic bronchitis, would indicate that in the observable range of ambient levels, effects are being seen without any apparent "threshold".  The EPA has recognized this lack of a threshold by considering a range of NAAQS for PM2.5 from a daily average of 20 micrograms per cubic metre up to 65 micrograms per cubic metre and from 12 micrograms per cubic metre up to 20 micrograms per cubic metre for an annual average.  Certain endpoints, especially those in the upper respiratory tract such as chronic bronchitis, indicate a continuing concern should be attributed to the coarse fraction of PM10.  The logical consequence of the health data is that the lower the ambient standard, the greater the health benefit.  Although Canadian particulate concentrations are, on average, lower than American levels, recent Canadian studies show that health effects are consistently related both in type and magnitude to particulate concentrations even at the lower ambient levels observed in Canada. This has also been observed in studies in other countries. In other words, benefits can be expected to accrue to Canadians with the implementation of objectives at lower than current ambient levels.  As has been clearly noted in the U.S. assessment, Canada's science assessment of particulate matter finds adverse health effects at the ambient levels of PM currently being experienced by the Canadian population. The debate on recommendations for particulate objectives currently underway in Canada is focusing on levels for Canada which span those in the full range considered by the U.S. EPA, with emphasis on values towards the lower end of that range.

 | What's New <http://www.ec.gc.ca/wneweng.html> | About Us <http://www.ec.gc.ca/introec/index_e.htm> | Topics <http://www.ec.gc.ca/environment_e.html> | Publications <http://www.ec.gc.ca/pands_e.html> | Weather <http://weatheroffice.ec.gc.ca/canada_e.html> | Home <http://www.ec.gc.ca/regeng.html> |

| Français <matterf.html> | Fran&ccedilais <http://www.ec.gc.ca/fenvhome.html>| Contact Us <mail/comment_air.htm> | Contact Us <http://www.ec.gc.ca/comments_e.html>| Help <http://www.ec.gc.ca/help_e.html> | Search <http://www.ec.gc.ca/search_e.html> | Canada Site <http://canada.gc.ca> | 

The Green LaneTM, Environment Canada's World Wide Web site

Last updated: 2002-12-19 Last reviewed: 2002-09-15

Important Notices and Disclaimers <http://www.ec.gc.ca/copy_e.html>

URL of this page: http://www.ec.gc.ca/air/qual/matter.html