What causes PM2.5 pollution?

Answer 1

PM2.5 (respirable particulate matter) material is primarily formed from chemical reactions in the atmosphere such as fuel combustion (e.g., motor vehicles, power generation, industrial facilities, residential fire places, wood stoves and agricultural burning) and by soil erosion by the wind

Because of the ease of transport in the wind problems created in one jurisdiction can impact another. As an example large amounts of PM2.5 are carried into Ontario from the U.S. and up to 50%r cent of Ontario's PM2.5 comes from the U.S.