Milwaukee air quality surges above 500 as Canadian wildfire smoke creates worst conditions on record

When wildfires burn, smoke can travel long distances and degrade air quality far away, posing risks to those breathing it.

Fires burning in one state can make the air worse several states away, and wildfires in Canada can send smoke into U.S. cities. Here’s what to know about taking precautions against poor air quality due to wildfires.

WHAT COUNTS AS BAD AIR?

The Environmental Protection Agency’s Air Quality Index converts all pollutant levels into a single number. The lower the number, the better.

Anything below 50 is classified as “healthy.” Fifty to 100 is “moderate,” while 100 to 150 is unhealthy for “sensitive groups,” and anything above 150 is bad for everyone.

Sensitive groups include people with asthma, lung disease or chronic obstructive pulmonary disease, said Dr. Sanjay Sethi, chief of the division of pulmonary, critical care and sleep medicine at the University at Buffalo medical school.

“If you have heart or lung problems, then you’ve got to be definitely more careful,” Sethi said. “I would either avoid going outside or wear an N95 or at least a dust mask.”

IS MY AIR UNHEALTHY?

In southeastern Wisconsin, wildfire smoke from Canada pushed air quality to hazardous levels Thursday, prompting the Wisconsin Department of Natural Resources to urge residents to stay indoors whenever possible. Milwaukee’s Air Quality Index climbed above 500, far beyond the 300 threshold the U.S. Environmental Protection Agency classifies as hazardous and exceeding the upper end of the standard federal AQI scale.

“As the worst air quality on record for our community continues to impact Milwaukee County, I encourage everyone to take this situation seriously, limit time outdoors when possible, and follow guidance from public health officials,” said Milwaukee County Executive David Crowley.

Dense smoke reduced visibility and exposed the entire population to dangerous concentrations of fine-particle pollution. State officials warned that even healthy people could experience eye irritation, coughing or shortness of breath during prolonged outdoor exposure.

The Wisconsin DNR said air quality is expected to improve gradually Friday as winds shift, but smoke is likely to linger across eastern Wisconsin, including the Milwaukee area, through at least part of the day. Forecasts call for conditions to remain degraded before cleaner air gradually arrives later Friday, meaning residents should continue limiting strenuous outdoor activity until air quality improves.

Across Milwaukee County, the hazardous conditions disrupted daily operations. Highway crews suspended nonemergency outdoor work requiring prolonged exposure, while county officials closed beer gardens, splash pads, pools and wading pools. Milwaukee County Transit System operators were also directed to minimize outside air entering buses by keeping windows, doors and roof hatches closed whenever practical.

Residents can monitor real-time conditions through the Wisconsin DNR’s air monitoring network and the U.S. Environmental Protection Agency’s AirNow website, as smoke concentrations can vary considerably across neighborhoods and change rapidly as wind patterns shift.

Sometimes the air is bad enough to see or smell the smoke. Even if you don’t see the pollution, it can be unhealthy to breathe.

The EPA maintains a website with up-to-date, regional air quality information. PurpleAir, a company that sells air quality sensors and publishes real-time air quality data, has a citizen scientist air quality monitoring network with a more granular map of street-by-street air quality readings.

The best way to get indoor air quality readings is to buy a monitor, said Joseph Allen, director of Harvard University’s Healthy Buildings Program.

“You can find these low-cost, indoor air quality monitors just about everywhere online now. They don’t cost all that much anymore,” he said.

WHAT IF I HAVE TO GO OUTSIDE?

For most people, going outside for just a short time won’t have a negative long-term impact, said Sethi.

Wearing an N95 mask, which became common during the coronavirus pandemic, will help filter out the pollution.

“N95 is going to get rid of 90-95% of the particles,” said Jennifer Stowell, a research scientist at Boston University’s Center for Climate and Health. “If you have access to a mask that has a respirator-type attachment to it, then that’s the very best.”

If you must be outside and you experience symptoms, experts say you should head indoors or elsewhere with better air quality. Even if you are healthy, it’s good to take precautions.

Milwaukee County officials also advised transit riders to check bus arrival times before leaving shelter to reduce the amount of time spent waiting outdoors.

“If you start wheezing, which is like this whistling sound of the chest, or if you’re feeling short of breath, that’s definitely more concerning,” Sethi said.

Milwaukee County officials said anyone experiencing difficulty breathing, chest pain, severe coughing, dizziness or other serious symptoms should call 911 immediately.

HOW DO I MAKE MY AIR CLEANER?

Close the windows and turn on the air conditioner, if you have one, setting it to circulate the indoor air. Use blankets to cover cracks that allow outside air into your home, such as under doors.

Finally, swapping the air conditioner’s filter for a MERV 13 filter can help, but ensure it’s installed correctly.

“If you happen to have access to an air purifier, even if it’s just a room air purifier, try to keep it running and in the room that you’re doing most of your activities in,” said Stowell.