Particulate Matter (PM) or particle pollution
Particulate Matter (PM) or particle pollution is a general term for a mixture of solids and liquid droplets suspended in the air: nitrates and sulfates, ammonium, water, black carbon, organic chemicals, metals, and soil (crustal) material. European Pollution Agency (EPA) groups PM into two categories upon their dimension:
1. Coarse particles (PM10-2.5) having the diameter from 2.5 to 10 micrometers, such as those found near roadways and dusty industries.
2.Fine particles (PM2.5) have diameters less than 2.5 microns, such as those found in smoke and haze.