: Large-scale industrial facilities, power plants, and refineries release significant amounts of SO2cap S cap O sub 2 and heavy metals like lead.

Air pollutants are categorized by how they enter the atmosphere:

Dispersion refers to how pollutants spread and dilute in the atmosphere. It is determined by several critical environmental factors: Air Pollution and Your Health

: Internal combustion engines in cars, trucks, and airplanes are responsible for up to 80% of urban pollution, emitting COcap C cap O NOxcap N cap O sub x PMcap P cap M

Air Quality Control: Formation, Sources, and Dispersion Air quality control is a critical multifaceted approach to managing the hazardous substances—including solid particles, liquid droplets, and gases—that contaminate our atmosphere. Effective control requires understanding how these pollutants form, where they originate, and how they disperse across geographic boundaries. 1. Formation and Classification