ANCHORAGE (KTUU) - In the Environmental Protection Agency's gradation of air quality levels, a red color key indicates "Unhealthy" particulate levels when PM 2.5 is above 150. A purple color indicates "Very unhealthy" levels, which range from 201 to 300, and a dark maroon color indicates the "hazardous" level of 301-500.
But there are no colors for when the levels exceed 500 as they are doing at stations around Southcentral.
A monitoring station near Willow blew the top off of that chart with a PM 2.5 reading of 598 on the PurpleAir citizen monitoring website. While levels have dropped back down to below 100, the weather pattern isn't suggesting any relief from the McKinley and Deshka Landing fires' smoke.
PurpleAir uses a different, less-expensive laser technology than official government monitoring stations, but are updated every 80 seconds, according to the website. While they are known to have different readings than government stations, numbers adjusted for that variability indicate equally high values.
Other monitoring stations along the Parks Highway show nearly as high of levels. A station on Kenai Lake recorded a measurement of 592.
The Environmental Protection Agency has a guide for what to do if levels are above hazardous. Among the recommendations are to stay indoors, avoid physical activity, and use air filters and air masks.
Anchorage PM 2.5 levels at the official Department of Environmental Conservation Garden Street monitoring station in Airport Heights, has been as high as 215 yesterday, but have started to slow since then.
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