Report: Western Wildfires Undermining Progress on Air Pollution

by Climate Central

  • States that wildfires are a source of an especially problematic type of air pollutant known as PM2.5 (“particulate matter” less than 2.5 microns in diameter)
  • States that PM2.5 can become lodged in lungs and cause or exacerbate a wide array of health problems such as asthma and heart disease
  • Analyzes air quality trends from 2000 through 2016 in two large California air basins that are heavily affected by smoke pollution, focusing on PM2.5
  • Compares the number of days PM2.5 exceeded federal standards at at least one station in each air basin for the entire year, with the number of days the pollutant exceeded federal standards during the summer wildfire season from June to September
  • Finds that while the air is getting cleaner overall in recent years, it’s getting dirtier during the fire season —  a season that research has shown is growing longer in the western United States