Worst air quality on record Thursday in Minnesota

Air quality monitors record highest readings ever in St. Cloud

Another week, another poor air quality record.

A dirty smoke plume above the Weather Lab Thursday afternoon
A dirty smoke plume obscures the sun above the Weather Lab Thursday afternoon
Paul Huttner | MPR News

Air quality monitors in Minnesota recorded the highest particulate readings on record Thursday, according to data from the Minnesota Pollution Control Agency. Most MPCA monitors came online in 2000.

The air quality monitor at St. Cloud hit an astounding 422 micrograms per cubic meter at 11 a.m. Thursday.

The St. Cloud reading breaks the record set a couple of hours earlier at Brainerd of 401 micrograms per cubic meter. Both readings broke the record set in last week’s smoke event at Red Lake of 397 micrograms per cubic meter.

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Here’s more from my email exchange with Nick Withcraft at MPCA Thursday:

Hi Paul,

We initially set a new high at Brainerd (401 ug) , then a couple hours later we set another new high at St Cloud (422ug)! These are the 1 hour readings at our monitors as reported on the Airnow website. We set 2 record highs in one day!



Air quality in the Twin Cities peaked in the very unhealthy range Thursday.

Air Quality Index readings in the Twin Cities Thursday
Air Quality Index readings in the Twin Cities Thursday
Minnesota Pollution Control Agency

Air quality readings across much of Minnesota remained in the unhealthy to very unhealthy range Thursday afternoon. The highest readings favored the western half of Minnesota.

Air Quality Index Thursday
Air Quality Index at 3 pm Thursday
Minnesota Pollution Control Agency

Visible from space

The thick smoke plume over Minnesota is clearly evident from 22,000 miles in space on NOAA’s GOES-16 weather satellites.

Northerly winds behind Wednesday night’s storm-producing cold front blew the smoke straight into Minnesota from Canadian wildfires to the north.

As high-pressure drifts east of Minnesota Friday, winds will shift back into the southwest. That should disperse much of the smoke by Friday afternoon. NOAA’s NAM 3 km model shows the forecast trend.

NOAA NAM 3 km model winds through Friday
NOAA NAM 3 km model winds through Friday
NOAA via tropical tidbits

An air quality alert remains in effect until 3 p.m. Friday for most of Minnesota.

Correction (July 30, 2021): Nick Witcraft’s name was misspelled in an earlier version of this story.