How much wildfire pollution enters your home depends on your behavior, study says
What you do in your home as wildfires rage outside can significantly reduce — or increase — the amount of smoke pollution you are exposed to, according to a new study.
Based on more than 2.4 million hours of indoor and outdoor air sensor data in over 1,400 California buildings, the study found that closing windows and running an air filter can cut the amount of tiny harmful particles from smoke inside a home by half on days when wildfires burn.
Though less controllable, the characteristics of your home make a difference, too.
The University of California, Berkeley, researchers found that homes constructed more recently and those built with central air conditioning were “significantly better at keeping wildfire smoke out.”
While the study’s findings were expected, the team says its research fills some gaps that other similar research has neglected: the concentration of smoke pollution indoors — where people spend most of their time — and how simple indoor efforts are paying off.
The paper was recently published in the journal PNAS.
“One thing that we’re deeply interested in is understanding what happens to people in indoor environments, because that’s where people spend most of their time, and there’s still an awful lot we don’t know about indoor pollution exposure,” study co-author Joshua Apte, an assistant professor of civil and environmental engineering and of public health at UC Berkeley, said in a statement. “I think that these new methods of sensing the indoor environment are going to allow us to grapple a lot more with questions of environmental justice and find out more about who gets to breathe cleaner air indoors.”
The team analyzed air sensor data in San Francisco and Los Angeles area buildings collected during August and September 2020, when the regions experienced a high number of “fire days.” These days are those that exceeded average levels of particulate matter in the air deemed safe by the Environmental Protection Agency.
Researchers also studied the real estate website Zillow “to estimate the characteristics of buildings.”
Although scientists are still trying to learn what types of chemicals are lodged in wildfire smoke, some evidence suggests “it may be even worse for human health” than particulate matter from other sources, the researchers say.
Not everyone has the same sensitivity to wildfire smoke, but the EPA says the mixture of microscopic particles and gases can get stuck deep in your lungs, triggering burning eyes and runny noses for some. The pollution can also aggravate chronic heart and lung diseases.
How to reduce exposure to wildfire smoke pollution indoors
Aside from closing your windows before smoke arrives in your area, setting up an efficient air filter can help reduce your exposure to wildfire smoke — and its location matters.
The team suggests setting it in your bedroom if you only have one in your home. Make sure the door is closed while you sleep to ensure the air is as clean as possible.
Try to cook as little as possible when fires are burning, too.
Cooking can produce its own harmful particles and gases that cannot be “easily ventilated out of the house without inviting wildfire smoke in,” the researchers said. The same thinking applies to kitchen and bathroom exhaust fans, which can pull in smoky air from the outside.
If you can’t afford a portable filter or a home with central air conditioning, the team suggests making your own with a box fan, a furnace filter and some tape.
This story was originally published September 2, 2021 at 3:30 PM with the headline "How much wildfire pollution enters your home depends on your behavior, study says."
