Clean air is important for all life on earth. Air pollution has been related to a range of adverse health and environmental effects such as respiratory infections and acid rain. Trees absorb CO2 through photosynthesis to produce oxygen for us to breathe, and intercept air borne particles on leaf surfaces. They also play a critical role in capturing the six common air pollutants and toxic gases: ground-level ozone, particulate matter, carbon monoxide, nitrogen oxides, sulfur dioxide and lead. These pollutants come from dust, pollen, ash, motor vehicles, power plants and other industrial sources. By planting trees and restoring forests we can help minimize the problem of air pollution.