Mitigating the Public Health Impacts of Prolonged Wildfire Smoke Exposure: Determinants of Portable Air Cleaner Use in Rural Washington State Communities

Higher temperatures and less precipitation during summer months due to climate change have increased both the frequency and scale of wildfires in Washington state, and in turn, the duration and intensity of wildfire smoke to which communities across the state are exposed. The Methow Valley, a rural community in the foothills of North Cascades National Park with around 6,000 residents, is among the communities most impacted by this increase in wildfire smoke exposure. In the summer of 2021, residents of the Methow Valley were exposed to 38 consecutive days of unhealthy, very unhealthy, or hazardous air quality as smoke from two nearby wildfire complexes blanketed the Valley. A growing body of research has linked wildfire smoke exposure to numerous health and well-being impacts, including damage to respiratory and cardiovascular function and increased prevalence of anxiety and depression. Children, older adults, those with pre-existing health conditions, and populations exposed to concomitant environmental injustices, such as low income populations and people of color, are the most likely to experience adverse health impacts from extended annual wildfire smoke exposure. As climate change projections indicate that wildfire activity will likely continue to increase in the coming decades, the Methow Valley and other Washington communities that experience a high annual burden of wildfire smoke need interventions that reduce exposure to smoke to mitigate these public health impacts. Portable air cleaners (PACs), including high efficiency particulate air (HEPA) PACs and box fans with attached minimum efficiency reporting value (MERV) 13 or higher furnace filters, are increasingly being recommended by public health officials as an intervention to reduce wildfire smoke exposure. While a number of studies have found that PACs are effective at reducing indoor air pollution from wildfire smoke, research on their implementation as a wildfire smoke intervention in real-world settings is limited. Over the past several years, a number of PAC distribution programs and education campaigns have occurred throughout the Methow Valley and in neighboring Washington communities. This study conducted a series of longitudinal, pre- and post-wildfire season surveys in 2022 and 2023 with recipients of these PACs, as well as other community members with a PAC in their household. Study findings document the perceived protection afforded by PACs, barriers and facilitators to PAC use, as well as how household characteristics, perceived impacts of wildfire smoke exposure, and available information sources about air quality influence PAC use. This research contributes to a foundational understanding of how those most impacted by wildfire smoke perceive and use a widely recommended public health intervention, which can inform future PAC distribution efforts, and highlights the need for further research into the effectiveness of PACs as a wildfire smoke intervention in real-world settings.