Minnesota has the worst air quality in the United States today because of smoke from Canadian wildfires blowing across the Gopher State.

The air quality was considered unhealthy and very unhealthy across a large swath of the state Wednesday afternoon. It was the worst in the cities and towns from Grand Forks to Minneapolis and from Mankato to Bemidji, according to AirNow.gov.

The AQI reached at least 204 in St. Cloud, 212 in St. Michael, and 194 in St. Paul, according to AirNow.gov. And it was 204 in Winstead and 212 in Delano just before 4 p.m. Wednesday.

That’s very unhealthy air and those cities had some of the worst air quality in the nation today.

The air quality was much worse in Minneapolis (194) than in Los Angeles, where the AQI measured 45. And Bemidji (191) had much dirtier air Wednesday than New York (47).

An AQI from 0 to 50 is good air quality, from 51 to 100 it is considered moderate, from 101 to 150 it’s unhealthy for sensitive groups, from 151 and 200 it’s unhealthy, from 201 to 300 it’s very unhealthy, and 301 and above is hazardous, according to AirNow.gov.

Unhealthy air quality could cause serious health problems for people who are members of sensitive groups, which includes those with heart or lung diseases, older adults, and babies and children, according to AirNow.gov.

The main pollutant in Minnesota today was PM2.5, which is fine particulate matter that can bury itself deep inside a person’s lungs or get into their blood, according to the Centers for Disease Control and Prevention in Atlanta.

The PM2.5 particulates causing this afternoon’s hazy air are coming from the smoke from Canadian wildfires that has moved into Minnesota, according to the National Weather Service.

According to the CDC, unhealthy air can cause eye irritation, lung and throat irritation, trouble breathing, lung cancer, heart attacks, and more.

The bad air is expected to stick around for at least another day. The Minnesota Pollution Control Agency has issued an air quality alert for fine particle pollution through 6 a.m. Thursday, according to the weather bureau.

According to the weather bureau, those who are members of sensitive groups should avoid prolonged or heavy exertion while the public should limit prolonged or heavy exertion.

The agency also recommends that people reduce or eliminate activities that contribute to air pollution and keep their windows closed to prevent smoke from getting indoors.