Air pollution is the release into the atmosphere of various gases, solids, or liquid aerosols that exceed the capacity of the environment to dissipate, dilute or absorb these solids, liquids, or gases. Pollutants can reach concentrations that cause health, economic, and/or aesthetic problems. Smog is a common example of an air pollutant. Others include ash, soot, arsenic, emissions from pulp and paper plants or chemical plants.
Greenhouse gasses absorb and emit radiation in a process known as the greenhouse effect. The main greenhouse gases include: water vapor, carbon dioxide, methane, nitrous oxide, and ozone. Greenhouse gases have been increasing due to human activities, such as industrialization. The concern is that the greenhouse effect is resulting in global warming, which can destroy ecosystems and make organisms extinct.