Air Quality 101

Air is all around us. We can’t see it, but we still breathe over 3,000 gallons of air each day.

So what is air, exactly?

The air in Earth’s atmosphere is a mixture of different gases made up of approximately 78 percent nitrogen and 21 percent oxygen. Air also has small amounts of lots of other gases, such as carbon dioxide, neon, and hydrogen. Many kinds of air pollution are invisible as well, yet they have very real consequences to human health, as well as the health of plants and animals.

There are four general categories for sources of air pollution. These are mobile sources (cars, trucks, buses, planes, and trains), area sources (agricultural areas, cities, wood burning fireplaces), stationary sources (power plants, oil refineries, industrial facilities, factories), and natural sources (wildfires, volcanoes, wind-blown dust). Sources of air pollution are diverse, change, and sometimes it’s not very clear exactly where the pollution comes from, especially for pollutants that are created in the atmosphere instead of directly emitted.