Characterization of Particulate Matter in Multi-Zonal Residential Apartment: Transport, Exposure, and Mitigation

ALOK KUMAR THAKUR, Sameer Patel, Indian Institute of Technology Gandhinagar

     Abstract Number: 281
     Working Group: Indoor Air Purification Technologies, Best Practices, and their Health Impacts

Abstract
Due to rapid urbanization and lifestyle changes, people in developing countries like India spend most of their time indoors, just like those in developed countries. However, indoor air pollution (IAP) studies in urban built environments in India are yet to gain impetus as most studies focus on ambient pollution. A few studies conducted so far are restricted to reporting pollutant concentration, providing limited insights into the source, transport, and fate of pollutants. Comprehensive studies are critical to assessing IAP severity and developing and deploying effective mitigation strategies in built environments.

We performed spatio-temporal monitoring of particulate matter (PM) in a multi-zonal residential apartment using a network of low-cost air quality monitors and research-grade instruments to characterize emission sources, assess transport metrics, estimate spatial exposure, and calculate I/O ratios. Exposure reduction efficacy of different mitigation measures was also tested. Sub-micron particles dominated number size distribution for cooking and incense. Operation of air conditioners (AC) led to faster transport of pollutants from the kitchen to the bedrooms. PM exposure in all zones relative to the kitchen ranged between ~0.8-0.9, indicating that occupants in and away from the emissions zone (kitchen) have comparable exposure. The average I/O ratios during cooking were elevated throughout the apartment, with the kitchen (10.1±8.9) and bedrooms (7.2±5.7 & 7.4±5.9) being the highest and lowest, respectively. Natural ventilation through balcony doors led to an average exposure reduction of 74-86% in different zones. AC operation reduced cumulative relative exposure, which was further reduced upon affixing a filter sheet on the AC pre-filter. Among the mitigation measures assessed, the highest cumulative loss rate (2.3±0.1 hr-1) was observed for the portable air cleaner with the default HEPA filter. The effect of increased filtration efficiency due to the added filter sheet was negated by the reduced flow rate.