Daily and Hourly Exposure to PM2.5 and Wildfire Smoke and Cognitive Performance in a Brain-Training Game: A Longitudinal Study of US Adults
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There is increasing evidence that long-term exposure to fine particulate matter (PM2.5) may adversely impact cognitive performance. Wildfire smoke is one of the largest sources of PM2.5 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 PM2.5 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 PM2.5 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 PM2.5 exposure were negatively associated with attention score. A 10 µg/m3 increase in PM2.5 in the 3 hours prior to gameplay was associated with a 21.0 [3.3, 38.7] point decrease in score. PM2.5 exposure over 20 plays accounted for an estimated average 3.7% [0.7%, 6.7%] reduction in the average final score of 14,251 points. Associations with PM2.5 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 PM2.5 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.