Update: The Sacramento Metropolitan Air Quality Management District revised Sunday’s forecast to 126 AQI, down from its previous estimate. It also said Saturday’s AQI had a maximum reading of 97.
Original story: Air quality in the Sacramento region is expected to be unhealthy for sensitive groups Saturday and Sunday, in part because of a 9,000-acre fire burning in southern Oregon, triggering a Spare The Air alert.
The region’s Air Quality Index is projected to rise to 126 on Saturday and 140 on Sunday, according to the Sacramento Metropolitan Air Quality Management District. Friday’s AQI reading was 115, the district said.
A “good” AQI – a combined measurement of particulate matter and ozone – is measured between 0 and 50 while “moderate” quality is between 51 and 100. A Spare the Air alert is issued whenever ground-level ozone pollution reaches 126, according to the district.
Sacramento, Yolo, Placer and El Dorado counties are expected to be affected throughout the weekend as local temperatures reach 104 degrees. Air quality is expected to be moderate Monday.
The Milepost 97 fire began Wednesday night near the Oregon town of Canyonville and had chewed through 6½ miles by Saturday morning. In addition, limited wind in the Sacramento area means ozone produced by the fire won’t be swept away until Monday.
“Potential smoke transport from the Milepost 97 fire in southern Oregon will enhance ozone production. As a result, ozone levels will be unhealthy for sensitive groups on both days,” Spare The Air’s website read. “Monday, moderate onshore winds will effectively disperse pollutants, and cooler temperatures will inhibit ozone formation.”
Smoke from the wildfire was creating hazy conditions in Redding on Saturday, as well.