Environmental pollution, particularly air pollution, is now a worldwide problem. Pollution represents a challenge not only to human health, but also to animals and plants.  In turn, human health will also be affected. The immune system is also sensitive to any environmental changes. The immune system itself consists of multiple types of immune cells that act together to generate (or fail to generate) immune responses. Understanding the effects of ambient pollutants on the immune system is vital to understanding how pollution causes disease, and how that pathology could be abrogated. It is also aimed to know how to lessen or prevent their effects on human health.