Assessing Atmospheric PM2.5 as a Proxy for Subjects’ Exposure Through Seasonal, Floor, Source-Specific Analysis
摘要
Most studies use atmospheric PM2.5 data to investigate its health effects and the impact of outdoor air on indoor PM2.5. However, people spend most of their time indoors, studies have not investigated whether atmospheric PM2.5 can represent the indoor and outdoor PM2.5 of buildings. This study collected indoor, outdoor (balconies), and atmospheric (rooftop) PM2.5 samples across different floors and seasons to assess representative of atmospheric PM2.5 in exposure assessment and impact analysis. Factor analysis and lead isotope ratios were applied to identify pollution sources. Average PM2.5 concentrations were 18.2 ± 10.2 μg/m3, 31.8 ± 19.2 μg/m3, and 33.3 ± 23.5 μg/m3 in indoor, outdoor, and atmospheric samples, respectively. Atmospheric and outdoor PM2.5 concentrations have significant correlations and showed no differences across floors and seasons. Although atmospheric PM2.5 concentration was associated with indoor PM2.5, atmospheric PM2.5 concentration was higher than indoor PM2.5, especially in the high PM2.5 season. Traffic-related emissions were major sources of indoor, outdoor, and atmospheric PM2.5, with long-range transportation from China also contributing to PM2.5 in the high PM2.5 season. Significant differences were observed in elemental concentrations between indoor, outdoor, and atmospheric PM2.5, with varying correlation coefficients among them. These findings highlight that: (1) atmospheric PM2.5 data can represent outdoor PM2.5 but indoor PM2.5 sampling is essential for accurate exposure assessment, (2) atmospheric PM2.5 sources were similar with indoor and outdoor PM2.5, and (3) collecting both indoor and outdoor PM2.5 is necessary to estimate exposure to specific elements and assess the impact of outdoor air on indoor environments.