Assessment and mitigation of indoor human exposure to fine particulate matter (PM2.5) of outdoor origin in naturally ventilated residential apartments: A case study

Emissions of fine particulate matter (PM_2.5) from on-road traffic and their influence on air quality and human health are of major concern in urban areas. Exposure to traffic-related PM_2.5 indoors has received considerable attention as people spend about 80% of their time in indoor environments, but little information is currently available on the assessment and mitigation of this exposure. A systematic field study was conducted with the key objective to assess and mitigate indoor human exposure to traffic-related PM_2.5 in a typical naturally ventilated residential apartment. Results indicated that traffic-related PM_2.5 levels indoors exceeded the air quality guidelines (12 μg/m³), and the PM_2.5 levels decreased significantly (74%) while using an indoor air cleaner. The human health risk assessment based on the bioavailable fraction of toxic trace elements revealed a substantial reduction in potential health risk while using the air cleaner. Overall, the major outcomes of this study would help develop effective air pollution control strategies to reduce indoor human exposure to PM_2.5 and potential human health risk caused by vehicular pollution in urban areas.