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
PM2.5 material is primarily formed from chemical reactions in the atmosphere and through fuel combustion (e.g., motor vehicles, power generation, industrial facilities, residential fire places, wood stoves and agricultural burning). Significant amounts of PM2.5 are carried into Ontario from the U.S. During periods of widespread elevated levels of fine particulate matter, it is estimated that more than 50% of Ontario's PM2.5 comes from the U.S.
|Other PM2.5 Industrial Processes||15%|
|Cement and Concrete Industry||5%|
Note: 2012 is the latest complete inventory. Emissions may be revised with updated source/sector information or emission estimation methodologies as they become available.
Approximately 39% and 22% of PM2.5 emitted in Ontario in 2012 came from residential and transportation sectors, respectively, while other PM2.5 industrial processes accounted for 15%. Lesser sources of PM2.5 include smelters/primary metals, miscellaneous, and cement and concrete industry.
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.