Air Health Indicator – Ozone and Fine Particulate Matter

The Air Health Indicator (AHI) provides a view of the public health impacts attributable to outdoor air pollution in Canada. It shows an upward trend in cardiopulmonary mortality attributable to ozone exposure. No upward or downward trend in cardiopulmonary mortality attributable to fine particulate matter (PM2.5) exposure is observed.

Cardiopulmonary mortalities are not the result solely of air pollution exposure (ozone and fine particulate matter) but rather the combination of a variety of risk factors. Other risk factors that contribute include age, sex, race, obesity, smoking history, education, marital status, diet, alcohol consumption and occupational exposures. The AHI aims to identify the risk factor for cardiopulmonary mortalities related solely to exposure to air pollution.

The ozone component of the AHI model predicts that 5% of cardiopulmonary mortalities were attributable to ozone exposure in 1990, increasing to 5.5% in 2008. The PM2.5 component of AHI suggests neither an increasing nor decreasing trend between 2000 and 2008. About 3% of cardiopulmonary mortalities could be attributable to PM2.5 exposure.

Cardiopulmonary (CP) mortality risk attributable to air pollutants

Chart: Cardiopulmonary (CP) mortality risk attributable to air pollutants

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How this indicator was calculated

Note: Percent CP Mortality Risk refers to the percent of cardiopulmonary mortalities estimated by the AHI model to be attributable to outdoor ambient ozone or PM2.5 concentrations. The study period is the 6-month warm season from April to September each year.
Source: Health Canada, Environmental Health Sciences and Research Bureau, Population Studies Division.

Canadians are regularly exposed to air pollution from outdoor sources such as transportation and industrial activities. This exposure can lead to the development of chronic lung disease, heart attacks and strokes, and to the onset or worsening of breathing difficulty. These health effects contribute to lost productivity, doctors’ and emergency room visits, hospital admissions and mortality. The AHI has been developed as a tool to monitor the impacts of outdoor air pollution exposure over time on the health of Canadians.

Specifically, the AHImonitors the percentage of all cardiopulmonary mortalities (deaths from heart- and lung-related disease) that can be attributed to exposure to 2 important outdoor air pollutants: ground-level ozone (monitored in 20 cities) and PM2.5 (monitored in 18 cities).


The AHI is different than the Air Quality Health Index (AQHI). Among the differences, the AHI is a national and annual indicator while the AQHI is location-specific and updated many times a day. For more information on the AQHI, visit Environment Canada AQHIwebsite.


Theme I: Addressing Climate Change and Air Quality of the Federal Sustainable Development Strategy.
This indicator is used to measure progress toward Target 2.1: Outdoor Air Pollutants – Improve outdoor air quality by ensuring compliance with new or amended regulated emission limits by 2020 and thus reducing emissions of air pollutants in support of AQMS objectives of the Federal Sustainable Development Strategy 2013-2016.