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Sunday’s air pollution was 13 times the national, health-based standards

Monday, September 14, 2020

Fine particle pollution measured in Spokane’s air yesterday (24 hour average) was 468.6 micrograms/cubic meter of air. This is more than 13 times the national, health-based standard of 35 micrograms/cubic meter of air, 24 hour average, midnight to midnight.

Concentrations of fine particles are converted to an Air Quality Index scale (AQI). Here is a chart of days over moderate since 1999, including concentrations and equivalent AQI reading.

Fine particles are microscopic in size, measuring 2.5 microns in diameter or smaller. These fine smoke particles can travel deep into the lungs, damaging and scarring delicate lung tissue. Read more about ways to protect yourself from wildfire smoke, including links to many other resources.

How long is this smoke going to last?
The massive smoke plume from the weekend has left our region covered by a thick layer of smoke. Although conditions should begin to improve somewhat this afternoon with the passage of a weak frontal system, poor ventilation combined with the inflow of smoke from active wildfires will cause smoke to remain trapped near the surface. Even as conditions slowly improve, the Air Quality Index may continue to reach the hazardous range at times today and tomorrow.


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