Air pollution poses a serious threat to human health. Those most at risk include children and the elderly, pregnant women and people already suffering from heart or lung disease. Asthma is one of the respiratory diseases that could kill people every year and who already suffer from heart or lung disease, and among most affected are children and elderly. Air pollution not only affects your health. It is also threatening some of our most valuable wildlife habitats; contaminating rivers, lakes and streams, damaging trees and endangering wildlife. Most of the air pollution come from motor vehicles, industry and waste disposal. By developing clean and efficient industrial processes and car engines we can help reduce air pollution.