a

atom

Glossary “atom” Definition:
1). Basic unit of matter consisting of protons, neutrons, and electrons arranged in such a way that retains its separate unique characteristics. 2). Smallest division of an element still retaining all of the original properties of the element.

atmospheric ozone

Glossary “atmospheric ozone” Definition:
As (UV) rays from the sun reach Earth, they are combined with smog and other pollutants to produce atmospheric ozone. Unlike stratospheric ozone, it is considered harmful and should be avoided.