PM2.5 emissions in the U.S. 2000-2023
PM.25 refers to particulate matter less or equal to 2.5 microns in diameters, and are typically composed of acids, organic chemicals, metals, and soil or dust particles, and are hazardous to human health. Many of the most polluted cities in the U.S. are located in California, though this is often a result of wildfires.