Air Quality Forecasts

There are currently two air quality forecasts that are publically accessible in Ontario. The first and oldest is the Ontario Ministry of the Environment's Air Quality Index and the second is Environment Canada and Health Canada's Air Quality Health Index.

Air Quality Index

Air Quality IndexSpecific air pollutants (ozone, fine particulate matter, nitrogen dioxide, carbon monoxide, sulphur dioxide, and total reduced sulphur compounds) that have an impact on human health and the environment are measured at monitoring sites set up throughout Ontario. Calculations are made hourly and the one pollutant with the highest reading becomes the Air Quality Index for that hour.  There are three categories in air quality forecasts: good (0 - 31), moderate (32-49) and poor (50+). A Smog Watch is issued when there is a 50% chance that smog levels will reach the poor category within the next 72 hours. A Smog Advisory is issued when the air quality forecast is expected to be poor within the next 24 hours or if poor air quality is unexpectedly in a particular region and will last for several hours. A Smog Termination notice is issued once the air quality has improved. To subscribe to the Smog Alert Network for your region, please visit http://www.airqualityontario.com/.

Smog Advisory Days History for the Halton-Peel Region

Year

Advisories

Total number of smog days

1993  

1

1

1994

2

5

1995

5

10

1996

2

3

1997

2

5

1998

3

7

1999

5

9

2000

3

3

2001

7

20

2002

9

18

2003

5

13 days (June 23, 24, 25, 26; July 1, 2, 3, 4; July 26; July 31, August 1, 20,21)

2004

6

14 days (May 8, 9, June 13, 14, July 21, 22, August 26, 27, September 4, 5, 6, 23, 24, 25)

2005

14

48 days (February 4, 5, 6, 7, April 19, 20, May 8, 9, 10, June 2, 3, 4, June 5, 6, June 8, 9, 10, 11, 12, 13, 14, June 24, 25, 26, June 27, 28, 29, 30, July 4, 5, July 11, 12, 13, 14, 15, July 21, August 3, 4, August 8, 9, 10, September 12, 13, 14, October 3, 4, 5, 6)

2006

5

11 days (May 28, 29, 30, 31, June 17, 18, 19, July 17, August 1, 2, 27)

2007

11

31 days (May 8, 9, 10, May 23, 24, 25, May 30, 31, June 1, 2, 3, June 13, 14, 15, 16, 17, 18, 19, June 25, 26, 27, July 10, 11, August 1, 2, 3, 29, September 6, 7, 19, October 5)

2008

6

13 days (April 18, 19, 20, June 13, July 7, 8, 16, 17, 18, 19, August 22, 23, September 3)

2009

2

4 days (May 21, August 15, 16, 17)

2010

2

7 days (July 4, 5, 6, 7, 8, August 30, 31)

2011

1

1 day (July 2)

2012

17 days (May 19, 20, 21, June 10, 11, 20, 21, 28, 29, July 13, 14, August 3, 4, 23, 24, 25, 26)

 2013

 1

 2 days (July 2, 3)

Air Quality Health Index

Air Quality Health IndexThe Air Quality Health Index (AQHI) was piloted in selected cities across Canada in 2005. On June 6, 2008, the AQHI was expanded across the Greater Toronto Area. Pollutants known to harm human health (ozone, particulate matter (PM2.5 and PM10) and nitrogen dioxide) are measured and calculations are made based on the cumulative impact of the pollutants. The index is based on a 10 point scale {low (0-3), moderate (4-6), high (7-10) and very high (10+) health risks} and provides health messages for both general and ‘at risk' populations. The information provided helps you to make decisions to protect your health by limiting short-term exposure to air pollution and adjusting your activity levels during increased levels of air pollution. It also helps you understand your response to different pollution levels to help you plan and enjoy outdoor physical activities at times when health risks are low. In 2012, a resource was produced titled "Air Quality Health Index Readiness Resource - Frequently Asked Questions."

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