Across the West, wildfires are increasing in frequency, intensity, and duration. In addition to ravaging landscapes and leveling communities, smoke from these fires has turned day into night in cities including Portland, Sacramento, and San Francisco and extended its reach as far east as Boston and New Your City. And with the smoke comes health risks, particularly for those with lung or cardiovascular disease, the elderly, and the young.
Elliott Gall spends a lot of time thinking about air pollutants such as wildfire smoke, particularly those in indoor environments--homes, schools, office buildings, and retail sites, where we spend the majority of our time. Gall is an assistant professor of mechanical and materials engineering and a member of the Thermal & Fluid Science group at Portland State University. His research aims to understand the mechanics and chemistry of indoor air pollution to inform how we design, build, operate and modify buildings to improve indoor air quality and protect health.
Gall recently received a three-year, $547,899 grant from the Environmental Protection Agency to conduct field and laboratory studies to improve our understanding of how common interventions (sealing buildings, altering HVAC operations, and using air filters) reduce exposure to indoor wildfire smoke in homes.
"When you have these wildfire smoke events, one aspect of prevailing public health guidance is to stay at home, indoors," Gall said. "Generally speaking, our indoor environments are protective of outdoor air pollution. But there is enormous variability and not all homes offer the same level of protection from the potential health risks associated with exposure to outdoor pollutants. We need to know what actions to take to reduce levels of wildfire smoke in our homes during these occasions when outdoor air pollution reaches ten or a hundred times that of normal conditions."
To gain that knowledge, Gall and his research team will take a three-pronged approach to study how wildfire smoke enters homes (and lingers in places you might not expect) and the efficacy of interventions for reducing the risk of exposure.
Want to create a safe space protected from wildfire smoke pollution in your home? Follow Gall's practical guide to creating a room nearly free of hazardous indoor air pollutants.
Two prongs of the study involve Gall and the research team building a tiny home structure in the lab. They plan to use the structure as a test chamber to evaluate the performance of commercially available and less expensive DIY air filtration systems and to study what happens to indoor surfaces after prolonged exposure to wildfire smoke.
Public health authorities recommend using air filtration devices during wildfire smoke events. Many of these machines effectively remove particles (a significant component of wildfire smoke). However, according to Gall, they're often not designed to treat gasses and because there is little research on the subject, we know much less about how effectively they filter harmful gasses in wildfire smoke. Gall's study will address this knowledge gap by evaluating how well various air cleaners improve air quality by removing certain gases (as well as particles) within the tiny home structure.
The research team will also use the structure to examine what happens to the surfaces inside buildings after several days or weeks of exposure to wildfire smoke. Specifically, the team will look at polycyclic aromatic hydrocarbons (PAHs), a family of compounds abundant in wildfire smoke that tends to stick to household surfaces, increasing the risk of exposure long after a wildfire smoke event. Gall plans to assess how long these compounds reside on surfaces and evaluate various cleaning methods to determine how effectively they remove the PAHs.
The third prong of the study involves working in the field, in homes in the Portland metro region. Gall plans to recruit homeowners to participate. Participants will allow the research team to test the efficacy of recommended interventions (such as sealing rooms, deploying air filters, and changing HVAC systems operations). The team will deploy these interventions and use specialized equipment to measure changes in the transport of air and particles from outdoors to indoors.
With data gathered from the three parts of the study, Gall can inform computer simulations that model the efficacy of interventions intended to reduce indoor wildfire smoke exposures.
"One of the things we want to know is if you run your home’s central air conditioner this way, will it introduce a bunch of wildfire smoke into your house? Or if you run it this way, will it help keep the pollutants out?" said Gall. "That is one of our goals with this study. We want to be able to make solid recommendations on things people can do quickly and inexpensively, even a day ahead of a wildfire smoke event, to improve the quality of air in their homes and reduce the health risks associated with wildfire smoke."