The year 2020 will be remembered for many reasons, including its record-breaking wildfires that turned San Francisco’s skies an apocalyptic shade of red and blanketed large parts of the West in smoke for weeks on end.
California experienced five of its six largest fires on record in 2020, including the first modern “gigafire,” a wildfire that burned over 1 million acres. Colorado saw its three largest fires on record.
While the smoke can make for beautiful sunsets, it can also have dire consequences for human health.
I am an atmospheric chemist, and the atmosphere is my laboratory. When I look at the sky, I see a mixture of many thousands of different chemical compounds interacting with each other and with sunlight.
The reactions and transformations in the atmosphere cause wildfire smoke to change dramatically as it travels downwind, and studies have shown that it can grow more toxic as it ages.