Fine Particulate Matter

What is fine particulate matter?

Particulate matter is characterized according to size - mainly because of the different health effects associated with particles of different diameters. Particulate matter is the general term used for a mixture of solid particles and liquid droplets in the air. It includes aerosols, smoke, fumes, dust, ash and pollen. The composition of particulate matter varies with place, season and weather conditions. Fine particulate matter is particulate matter that is 2.5 microns in diameter and less. It is also known as PM2.5 or respirable particles because it penetrates the respiratory system further than larger particles. PM2.5 in Ontario is largely made up of sulphate and nitrate particles, elemental and organic carbon and soil.

What are the sources of fine particulate matter?

PM2.5 material is primarily formed from chemical reactions in the atmosphere and through fuel combustion. Major sources of PM2.5 include motor vehicles, smelters, power plants, industrial facilities, residential fireplaces and wood stoves, agricultural burning and forest fires. Significant amounts of PM2.5 are carried into Ontario from the U.S.

What are the effects of fine particulate matter?

The greatest effect on health is from particles 2.5 microns or less in diameter. Exposure to fine particulate matter has been associated with hospital admissions and several serious health effects, including premature death. People with asthma, cardiovascular or lung disease, as well as children and elderly people, are considered to be the most sensitive to the effects of fine particulate matter. Adverse health effects have been associated with exposure to PM2.5 over both short periods (such as a day) and longer periods (a year or more).

Fine particulate matter is also responsible for environmental effects such as corrosion, soiling, damage to vegetation and reduced visibility.

How is PM2.5 monitored in Ontario?

In 2002, Ontario was the first province in Canada to introduce monitoring of PM2.5 to the Air Quality Index. The ministry reported real-time PM2.5 with the Thermo Scientific TEOM 1400AB/SES until December 31, 2012. Continuous PM2.5 monitoring technologies have evolved dramatically over the last decade.

In 2013, Thermo Scientific SHARP 5030 monitors were deployed across Ontario's air quality monitoring network. The SHARP monitors were able to detect additional components of PM2.5, especially during cold weather. As a result of this improvement in monitoring technology, there was potential to report higher PM2.5 concentrations during the winter months when compared to previous PM2.5 concentrations as measured by TEOM. These more accurate measurements did not necessarily mean that Ontario's air quality had changed.

In 2023, Ontario upgraded the PM2.5 network and replaced the SHARP monitors with the Teledyne API T640 monitors. PM2.5 measurements with the Teledyne API T640 and SHARP monitors are expected to be comparable.