Ideas in Action: Keeping buildings healthy during wildfires

You already know to stay inside when wildfire smoke is in the air, but should you turn on your air conditioner? And when the smoke is gone, how should you clean your home? 

These are the types of questions Elliott Gall, associate professor of mechanical and materials engineering in the Maseeh College of Engineering and Computer Science at Portland State University, is working to answer. Gall runs PSU’s Healthy Buildings Research Lab where he and his team of student researchers study indoor air pollution.

Gall was recently awarded a three-year $500,000 grant from the Environmental Protection Agency (EPA) to study ways to reduce indoor exposure to harmful pollutants from wildfires.

Preventing smoke infiltration

As part of this project, Gall and his students will take air quality measurements in multiple Portland homes next summer (they’re currently recruiting houses; if you’re interested you can email Gall). 

The goal is to get a better picture for how wildfire smoke infiltration is affected by interactions between parts of a building that separate us from the outdoors—like walls, floors, roofs, doors and windows—along with heating, ventilation and air conditioning (HVAC) systems.

Gall hopes that these results will lead to clearer recommendations for how to use air handling systems during a wildfire as well as guidance for HVAC and weatherization contractors so they can make buildings less susceptible to smoke infiltration in the first place.

Clearing the air

What about the polluted air that does sneak into our homes? Gall and his team are testing the efficacy of commercial air cleaners as well as the lab’s own award-winning low-cost DIY air cleaner. 

They have a unique setting in which to conduct these experiments: a very large stainless steel chamber that the group recently built.

“To have a fully controllable room-size environment all contained inside my lab is tremendous,” says Gall. “We can more directly say what a device does at a scale that's representative of how people will use it.”

Using this chamber, the researchers are finding out how well air cleaners remove both particulate matter and gasses found in wildfire smoke, some of which are known to be hazardous to human health.

So far the results suggest that many commercial air cleaners may not be so effective at removing gas compounds.

“If you're an average consumer reading specifications online you'll be under the impression that your cleaner does everything, but our testing is showing that that's not the case,” says Gall. “It’s difficult to remove this whole other class of compounds.”

That’s the bad news. The good news is that by setting a baseline for what these systems are currently able to do, Gall and other researchers will be able to engineer new solutions for cleaning air. 

“We can build on that to identify the most promising technologies and improve them or look for entirely new approaches for addressing this suite of pollutants that we really should be considering,” he says. 

Cleaning up 

Unfortunately, the effects of wildfire smoke don’t disappear when the skies clear. Gall is also researching how pollutants from wildfire smoke collect on home surfaces—and what to do about them.   

“Imagine someone smokes a few cigarettes in your home,” he says. “Even after they leave, you might still experience the aftereffects of that smoking long after the smoking ends.” 

The lab is particularly interested in a class of compounds called polycyclic aromatic hydrocarbons (PAHs). These are known human carcinogens that are elevated in wildfire smoke and can stick to surfaces like glass and cotton. 

The team has already made some encouraging findings. Just wiping with a surface cleaner is enough to “substantially reduce” PAHs from hard surfaces as is putting cotton through the laundry. 

“After a really bad wildfire event you might want to prioritize your bedding, for example, so that you don't crawl into bed and cover your skin in toxic PAHs for the week or month after a wildfire,” says Gall. He says to stay tuned for more info on how to clean other surfaces. 

Wildfires can be scary, but we might be able to breathe just a little bit easier the next time smoke is in the air thanks to Gall and the other researchers of the Healthy Buildings Research Lab.