Daily and hourly exposure to PM2.5 and wildfire smoke and cognitive performance in a brain-training game: A longitudinal study of US adults

There is increasing evidence that long-term exposure to fine particulate matter (PM_2.5) may adversely impact cognitive performance. Wildfire smoke is one of the largest sources of PM_2.5 today and concentrations are likely to increase under climate change. However, little is known about how short-term exposure impacts cognitive function. We aimed to evaluate the associations between daily and hourly exposure to PM_2.5 and wildfire smoke and cognitive performance in adults. Scores from 20 plays of an attention-oriented brain-training game were obtained for 10,228 adults in the United States (US). We estimated daily and hourly PM_2.5 exposure through a data fusion of observations from multiple monitoring networks. Daily smoke exposure in the western US was obtained from satellite-derived estimates of smoke plume density. We used a longitudinal repeated measures design with linear mixed effects models to test for associations between short-term exposure and attention score. Results were also stratified by age, gender, and region. Daily and hourly PM_2.5 exposure were negatively associated with attention score. Associations with PM_2.5 were more pronounced in the wildfire-impacted western US. Medium and heavy smoke density were also negatively associated with score. Heavy smoke density the day prior to gameplay was associated with a 117.0 [1.7, 232.3] point decrease in score relative to no smoke. Associations were most pronounced for younger (18-29), older (≥70), and male users. Our results indicate that PM_2.5 and wildfire smoke are associated with reduced attention in adults within hours and days of exposure, but further research is needed to elucidate these relationships and the potential impacts to affected populations. This abstract does not reflect EPA policy. Mention of trade names does not constitute endorsement or recommendation for use.

Stephanie Cleland is a PhD Candidate in Environmental Sciences & Engineering at UNC-Chapel Hill Gillings School of Global Public Health and an ORISE Research Fellow at the U.S. Environmental Protection Agency. She holds an MSPH in Environmental Health from UNC-Chapel Hill. Her current research focuses on using epidemiologic analyses, exposure assessments, and health impact assessments to evaluate the human health impacts of short-term exposure to climate change-influenced environmental hazards, such as wildfire smoke and extreme heat.