Fine Particulate Matter in the US

This map shows the EPA montoring stations for the criteria pollutant PM2.5 or fine particulate matter - basically dust particle less than 2.5 microns in diameter. Long-term exposure to PM2.5 has been linked to cardio-vascular disease and thousands of deaths annually.

Each station is represented by a circle, the darker the circle the higher the annual average PM2.5. Hovering over a circle shows the annual average PM2.5 for the years 2014-2016 (based on available data) for the station. Clicking on a station will display the station's hourly PM2.5 "heat maps" for each of the three years. Clicking on a heat map "square" will bring up a tool tip showing the date, time, and PM2.5 concentration for that hour. Additionally, there is a layer that shows all facilities in the 2014 NEI (National Emissions Inventory) that emit more than 100 tons of (primary) PM2.5 annually.

The heat maps show some interesting patterns - for example look for the high PM2.5 seen on the night of 4th July at Florida Hillsborough County Station 3002 or Montana Missouls County Station 24. The effect of the 2016 Fort McMurray wildfire can be seen in elevated PM2.5 levels in early May in North Dakota Williams County Station 3 and Minnesota Beltrami County Station 2304. Elevated winter PM2.5 levels at Washington Pierce County Station 29 may be indicative of winter woodfire burning and inversions.

Explore the heatmaps, and do drop us a line at if you spot something interesting - we will be happy to put it on our website.