Home of the U.S. Air Quality Index (AQI), this website provides information on AQI and health, wildfire and smoke maps, as well as maps and data by location.
This map, created by ProPublica, "highlights areas where the additional cancer risk is greater than 1 in 100,000 — 10 times lower than the EPA’s threshold, but still high enough to be of concern, experts say."
"CSL studies the processes that influence air quality on local, regional, and global scales to support informed air quality decision-making at local, state, national, and international levels."