Dense Smoke in Washington Palouse, Washington

An air quality sensor in Pullman recorded unhealthy air quality from September 12th through September 19th. It spiked to continuous hazardous conditions on September 13th through 15th. The arrival of a cold front on September 19th brought showers and westerly winds which ventilated the area.

Multiple large wildfires in Washington, Oregon, and surrounding states produced copious quantities of dense smoke throughout the month of September. Due to poor ventilation and a gradual return to southwest winds, there were increasing amounts of wildfire smoke to Washington. The smoke from these fires severely degraded air quality across much of eastern Washington in mid-September. Numerous communities, especially in the Spokane area, suffered long periods of very unhealthy to hazardous air quality.