This document discusses air pollution. It begins by defining air pollution and listing its sources as natural (such as dust, wildfires, volcanoes) and anthropogenic (point, area, line sources). It then classifies pollutants as physical (pollen, bacteria, dust) or chemical (primary emitted directly and secondary formed from reactions of primary pollutants). Several primary and secondary pollutants are identified. Permissible limits of several pollutants are provided. Carbon credits for reducing greenhouse gas emissions are also discussed. Global issues related to increased greenhouse gases and pollution are outlined. The document concludes by stating public health is at risk from air pollution and alternatives should be provided to reduce pollution risks.