The atmosphere is composed of gases such as oxygen, nitrogen and carbon dioxide. Other gases are present at much lower concentrations and include ozone, nitrogen oxides, sulfur oxides and formaldehyde just to name a few. But there is something else in the air we breathe: microscopic particles called aerosols. Vicki Grassian discusses aerosols, their many sources, and how they impact the Earth’s climate and human health in ways we are just starting to understand. Series: "Exploring Ethics" [Show ID: 33719]