COLUMBIA, S.C. — Our atmosphere is composed of a multitude of gases. There are two main ones that take up most of our air. Nitrogen is the biggest and takes up about 78 percent of the atmosphere.

We know those sunny days and May flowers are on the way, but we still have to get through a few more April showers (or, you know, snowstorms — hi, New England!) first. And while those showers are ...