“Ozone and PM” refers to data for Ozone plus PM2.5 plus PM10. Each hour, the highest among these 3 pollutants is displayed for each monitor and each contour. Click on a monitor to reveal and raw concentration data. Click “Plot Data” to see …

This map displays data from reference-grade air quality monitors at U.S. embassies and consulates around the world. Fine particulate matter (PM2.5) data is available for all sites, and ozone data is available for >10 sites.

USA map with PM2.5 speciation monitors depicted. Clicking a point opens a stacked bar graph depicting the 2000 to 2021 trends in PM2.5 speciation by component: sulfate, nitrate, …

USA map with PM2.5 speciation monitors depicted. Clicking a point opens a stacked bar graph depicting the 2000 to 2018 trends in PM2.5 speciation by component: sulfate, nitrate, elemental carbon, organic carbon, crustal material and sea-salt.

The 1990-2017 national trend line indicates a general decrease for the criteria air pollutant emissions. Directly emitted fine particle pollution (PM2.5) and ammonia (NH3) emissions have decreased little over the last decade. Both of these pollutants contribute to PM2.5 in the air.