Making sense of the Air Quality Index

The fire season in the Western United States this year has been unlike any before. In the last few weeks, fires have burned millions of acres of land in California, Oregon, and Washington. Tens of thousands of people have been forced to evacuate in the midst of a pandemic. Smoke has covered the entire western half of the U.S., and some cities have the worst air quality of the major cities around the world. But, many people are asking: We’ve been hearing a lot about air quality and indexes and orange and purple and “350” and “107.” What is all this jargon? What does air quality really mean, for our daily lives and for our health? If I’m healthy, do I really need to be concerned about this?