Wildfire season is over, but winter air quality still poses risk

By Lara Steen

My least favorite part of winter used to be the cold stinging my face. Now that I’ve learned to dress weather-appropriately, a new nuisance has replaced the cold: wood smoke.

Residential wood smoke causes both acute and chronic health problems. It harms not just those in the home but their neighbors too, both outside and indoors as it infiltrates through HVAC systems and other openings.

I miss the days when going outside in January meant only cold air in my lungs, and not smoke and particulates too.

Wood smoke can make average air quality even worse in winter than summer. Last summer, Canadian wildfires forced many Minnesotans to stay indoors and shut windows to avoid exposure to dangerous levels of particulate matter.

During one such day, I donned a mask to take out the garbage and realized the air I was protecting myself from wasn’t much worse than what I might typically experience during the winter!

In fact, between 2016 and 2021, the months of November through April had, on average, twice as many days with a moderate Air Quality Index, or AQI, as the summer months did.

“Moderate air quality” may not sound menacing, but long-term exposure to even low levels of fine particulate matter (PM 2.5) can increase the risk of lung cancer, chronic obstructive pulmonary disease, chronic bronchitis and cardiovascular disease.

Short-term exposure to high levels can cause heart attacks, irregular heartbeat and permanent lung damage, according to the Minnesota Pollution Control Agency.

The MPCA estimates that 51% of Minnesota’s PM 2.5 comes from burning wood, even though only 7% of Minnesotans use wood as their primary heat source, and only around half burn wood recreationally. This means a minority is responsible for a disproportionate amount of wood-fire-generated air pollution. If you live near such a household, your PM 2.5 exposure is likely much higher than the AQI on your favorite weather app may suggest.

We all are faced with many environmental challenges that demand our attention, but air quality is one for which small changes have a huge impact, especially on your friends and neighbors. Consider these tips for managing your impact, and learn more at epa.gov/burnwise.

If you burn wood for heat:

  • If you can, reduce burning on days with a thermal ­inversion — a common winter phenomenon in which air pollution gets trapped near the ground and causes higher AQI. The MPCA often issues air quality alerts on especially bad days.
  • Consider switching to a cleaner, more efficient heat source such as heat pumps, solar or geothermal. Tax credits may be available to help offset the cost of upgrading, and programs such as the Weatherization Assistance Program could also make it more affordable.
  • Use a stove certified by the Environmental Protection Agency, and burn dry, seasoned wood — not wet wood, trash or yard waste.
  • If you burn wood mostly for the cozy ambiance:
  • Consider candles instead. Scented candles can emulate the smell of a fireplace and emit a warm glow without releasing as many pollutants.
  • Replace your wood fireplace with an electric one: many of them replicate the ambiance of a wood fireplace well.

If you encounter wood smoke pollution:

  • Keep doors and windows closed when you can smell smoke.
  • Use an indoor air purifier and replace your HVAC air filter at least every six months. Turn off your air exchanger if you have one. You can also use an air quality monitor to measure specific pollutants in your home or outdoors.
  • Wear a high-filtration mask (N95 or similar) to minimize PM 2.5 inhalation.

Lara Steen, a recent graduate of St. Olaf College, lives in St. Anthony Park and works at Medallion Labs as a microbiology technician. Members of the SAP Community Council’s Environment Committee assisted with this article.

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Title: Average Number of Days with Moderate Air Quality Each Month (2016-2021)
Data from: Minnesota Pollution Control Agency Data Services

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