The arrival of the smoky Canadian air, which took a roundabout route in reaching the Red River Valley after first swooping through the Twin Cities, delivered some of the worst air quality in recent memory.
AirNow, a service of the Environmental Protection Agency, reported that as of 9 a.m. on Wednesday, Fargo-Moorhead had an air quality index of 161, which is unhealthy to breathe.
Earlier Wednesday morning, the air quality index in Fargo-Moorhead had reached 195 — a level considered very unhealthy by AirNow. By 3 p.m. Wednesday, however, the air quality index had improved to 99, moderate air quality.
AirNow quality index readings for Grand Forks were not available Wednesday afternoon, but the BreezoMeter app indicated that Grand Forks had moderate air quality with an index of 69.
The bout of unusually poor air quality was the result of the smoky Canadian air coinciding with a temperature inversion in which cooler air near the surface helped trap the haze, said Stormtracker chief meteorologist John Wheeler.
The plunge in air quality began in the wee hours, Wednesday, as