Ground-level ozone air quality indicator relative to the 2015 Canadian Ambient Air Quality Standards, Canada, 2000 to 2014

New fine particulate matter monitoring equipment was progressively introduced across Canada to replace older monitoring equipment from the mid-2000’s to 2014. These new instruments measure a portion (semi-volatile) of the fine particulate matter mass not captured by the older instruments. Due to the differences between the new and the old monitoring equipment, concentrations measured with the new monitors may not be directly comparable with measurements from years in which older instruments were used.

Source: CICH graphic created using data adapted from Environment and Climate Change Canada. 2016. Canadian Environmental Sustainability Indicators: Air Quality. – accessed March 12th, 2017.

There are a number of pollutants that can cause poor air quality – ground-level ozone (O3), sulphur oxides (SOX), nitrogen oxides (NOX), volatile organic compounds (VOCs) and solid and liquid particles called fine particulate matter (PM2.5).1

Smog is primarily made up of ground-level ozone (O3) ad fine particulate matter (PM2.5).  These pollutants can cause adverse health and environmental effects.1

Canada has set standards for air quality.  One air quality indicator that is monitored in Canada is the ground-level ozone, peak (4th-highest) 8-hour level. This indicator is based on the annual 4th-highest daily maximum 8-hour average concentrations and is used to capture immediate or acute short-term exposure.1

This indicator was below the standard from 2008 to 2014. In 2014, the O3 peak indicator was 14% below the 2015 standard.


Exposure to ozone has been associated with a number of health effects such as premature death, asthma and hospital admissions due to respiratory illness.1

1Environment and Climate Change Canada. 2016. Canadian Environmental Sustainability Indicators: Air Quality.  – accessed March 12th, 2017.