Human exposure to wildfires has more than doubled in two decades – read this if you're planning fireworks on July 4

A wildfire in 2017 destroyed more than 3,000 homes in Santa Rosa, Calif., a city of over 180,000 people. Marcus Yam / Los Angeles Times via Getty Images

Over the past two decades, a staggering 21.8 million Americans found themselves living within 3 miles (5 kilometers) of a large wildfire. Most of those residents would have had to evacuate, and many would have been exposed to smoke and emotional trauma from the fire.

Nearly 600,000 of them were directly exposed to the fire, with their homes inside the wildfire perimeter.