Abstract
BackgroundTo understand the effect of air quality on cognition, air quality measurements should reflect real-world exposure. Currently, air quality exposure is derived from outdoor air quality monitors despite older adults spending most of their time indoors.ObjectiveTo examine if there are discrepancies between indoor particulate matter 2.5 (PM(2.5)) at older adults' personal residences, PM(2.5) levels measured with nearest outdoor public air monitors, and remotely accessed gridded ensemble air quality data.MethodsPM(2.5) levels collected in older adults' residences, collected from the nearest outdoor public air quality monitors and ensemble data from Hazardous Air Quality Ensemble System (HAQES) were compared using Spearman correlation coefficients and Wilcoxon signed-rank tests. Daily PM(2.5) profiles in these homes were also examined.ResultsAmbient air quality was assessed in 23 residences of older adults from October 2021 to August 2024. Indoor PM(2.5) measurement was lower than outdoor public air monitors for all but 3 homes. Estimates of PM(2.5) level from HAQES were also significantly higher than those indoors. High inter- and intra-home variability over time was observed. Spikes in daily indoor PM(2.5) levels were common, and they could exceed the United States Environmental Protection Agency (US EPA)'s recommendation for 24 -hour average. Use of home appliances and indoor activities may contribute to changes in indoor PM(2.5) level throughout the day.ConclusionsTo optimally estimate air quality exposure risk, monitoring both indoor and outdoor environments is likely needed.