You may have noticed: something’s in the air. Smoke from wildfires out west has infiltrated our skies this summer, making for hazy days, ruddy sunsets, and air quality alerts.
If it seems like the number of alerts due to wildfires has increased in the past few years, you’d be right. According to MPCA’s staff meteorologists we’ve had 26 air-quality alerts since 2015, and 14 of those were due to wildfire smoke. That’s nearly double the number of smoke-related alerts the MPCA called in the previous seven years.
It’s one thing to get smoke impacts from home-grown wildfires, but in recent years we’re getting hit with smoke from fires burning more than a thousand miles from here. This year we’ve already had six alerts, and more are likely to come.
“These are long-range transport events,” says MPCA meteorologist Daniel Dix. “We’re just seeing many more bigger, hotter fires that generate these kinds of air-quality impacts for Minnesota.” While the massive fires in California are the ones we hear about, Dix said the fires that are dimming the sun in Minnesota this year have been mainly in British Columbia. (However, we are now seeing smoke from wildfires due north of Minnesota in western Ontario.)
“The California smoke is mainly blocked by terrain between us and them. But the fires in Canada are also huge, and when we get cool fronts from the Northwest, we’re right in the path of those plumes,” Dix said.
According to Steve Irwin, also an MPCA meteorologist, smoke from wildfires contains a variety of pollutants that are problematic for human health. “Smoke contains carbon dioxide, water vapor, carbon monoxide, particles, hydrocarbons, other organic chemicals, and nitrogen oxides. But the pollutant that’s the most concern is fine particles. Those are the ones that seem to do the most damage to the lungs and the heart.”
Fine particles, called PM2.5, are really small, with diameters of 2.5 micrometers and below. For comparison, a human hair is 50 to 70 micrometers in diameter.
PM2.5 has significant health effects, not just on the respiratory system but the cardiovascular system as well. When levels are forecasted to be in the orange range on the Air Quality Index, the MPCA calls an air quality alert. “Anyone can be affected depending on their level of activity,” Irwin said, “even if it’s a healthy person but they’re outdoors breathing hard and exerting themselves. But generally it’s going to be sensitive populations, those with lung conditions such as asthma or COPD, heart disease or high blood pressure, children and elderly.”
With “megafires” becoming the new normal in the west, Dix and Irwin expect we’ll see more of the same for years to come. Climate change is definitely a factor, but there are many reasons. Decades of fire suppression have built up massive amounts of fuel, Dix said, and the west is experiencing persistent drought and heat (July was the hottest month ever in California). But population also is expanding rapidly in forested areas.
“So you have all these other factors plus firefighters are trying to protect more property. Basically people are building homes where they really shouldn’t be. It’s like building homes along the Gulf coast, it puts people in a tough situation,” Dix said. “There’s so much to burn, and they burn so hot when they do fire up and go. When you look at a satellite map of all these wildfires, it’s incredible how many there are all up and down the west.”
The MPCA’s ability to monitor these distant smoke plumes and forecast their effect on air quality has been greatly enhanced by new systems the MPCA’s meteorologists have put in place. To stay informed visit the Air Quality Index page, where you can also download our Minnesota Air mobile app.