Air Pollutants & Sources

The primary pollutants found in the Fraser Valley include:

Ground-level Ozone (O3)

Ozone found high in the earth’s atmosphere helps protect us from the sun's rays. Ozone at ground level, however, is bad for human health and is the main ingredient in smog. Ground-level ozone forms when nitrogen oxides (NOX) and volatile organic compounds (VOC), the “precursor” chemicals, react in the presence of sunlight.

Sources: burning fossil fuels (gas, oil, coal) for industry and transportation


Fine Particulate Matter (PM)

Fine particulate matter refers to microscopic particles that pollute the air. PM2.5  is particulate matter that is extremely small (2.5 microns or less – the width of human hair). PM2.5 can be breathed deeply into your lungs and will stay there, causing health problems. 

Sources: fireplaces and woodstoves, forest fires, vehicle exhaust, road dust, industry

Sulphur Dioxide (SO2)

SO2 is a colourless gas that smells like a burnt match. When mixed with water in the atmosphere, it creates acid rain. Sulphur dioxide combines with volatile organic chemicals (VOCs) and sunlight creating ground-level ozone (see above).

Sources: steel mills, diesel vehicles, coal-fired power plants, volcanoes, aircrafts

Nitrogen Oxides (NOX)

This is the name given to a group of pollutants including nitric oxide (NO) and nitrogen dioxide (NO2). They are produced by fuel combustion and contribute to the formation of ozone, smog, and acid rain. Nitrogen oxides are reddish-brown gases that have a pungent smell.  

Sources: fossil fuels, forest fires, incineration, metal production

Carbon Monoxide (CO)

CO is a colourless and odourless gas generated by incomplete combustion of fossil fuels, such as coal, gasoline, or diesel. It is also released by wild forest fires and volcanic eruptions. In high concentrations, it is toxic to humans.

Sources:  house fires, faulty furnaces, heaters, wood-burning stoves, cars, propane-fueled equipment, gasoline-powered tools 

Volatile Organic Compounds (VOCs)

VOCs are carbon-containing compounds that are released primarily by the evaporation of petroleum products, such as gasoline, as well as solvents and other volatile products, such as paints. VOCs react with NOX in the presence of sunlight to form ground-level ozone. Some VOCs are carcinogenic (cancer-causing). 

Sources: gasoline, paint, hair spray, kerosene