Air Quality: Ground-Level Ozone

There are two types of ozone (O3), each affecting our quality of life. Naturally occurring as a gas in the stratosphere surrounding the earth, O3protects everything living on the surface from the harmful ultraviolet rays of the sun. However, ground-level O3, which is monitored by the SLEA, is formed through reactions of precursor compounds, like nitrogen oxides and volatile organic compounds, in sunlight and impairs the quality of our air.

At normal background levels, O3 is a colourless and odourless gas, forming a major component of smog. In addition to the amount of bright sunlight, temperature, as well as wind speed and direction, influence its formation. Elevated concentrations of O3 are often detected on hot, sunny days during the months of May through September. Health effects of O3include irritation of the respiratory tract and eyes, with children and people with respiratory disorders being the most vulnerable. Plants can also be adversely affected by O3, stunting the growth rates and yields of such species as white beans, potatoes and tomatoes.

SLEA consultants continuously measure Ozone present in the air. Hourly averages are recorded at monitoring stations in Corunna and Sarnia.

See the most recent Progress Review Technical Summary for details on Ozone.