Indoor Air Quality in Urban India: Current Status, Research Gap, and the Way Forward

Given that people spend most of their time indoors in developed nations, personal exposure occurring in indoor spaces dominates cumulative exposure. Therefore, the total mortality burden of air pollution is primarily attributed to indoor air pollution (IAP). Owing to rapid urbanization, people in India too have similar activity patterns. However, IAP research in urban-Indian built environments is still nascent relative to developed countries. This article comparatively reviews the research on the measurement, modeling, and mitigation of IAP in developed countries and India. While studies in developed nations have deployed state-of-the-art instrumentation for comprehensive characterization, similar studies in India are severely limited in quantity and scope. The lack of measurements has restricted robust follow-up studies of IAP modeling and mitigation. Fundamental studies on sources, transport, transformation, and the fate of pollutants in urban indoor spaces are nearly nonexistent. Such studies are critical for designing and operating built environments to shield occupants from indoor sources and outdoor air pollution, which are severe in urban India. Limited IAP measurements due to resource restrictions remain a critical bottleneck for IAP research in India. Shifting the focus of policymakers and the public from ambient air pollution to IAP is critical for IAP research in urban India.