Indoor Air Pollution in an Academic Institution: PM Levels, Chemical Composition, and Possible Health Impact

DEBAYAN MANDAL, Abhishek Chakraborty, Shruti Tripathi, Indian Institute of Technology Bombay

     Abstract Number: 630
     Working Group: Indoor Aerosols

Abstract
As 21st-century humans, we spend 85-90% of our time indoors. Historically ambient air pollution got more attention from researchers worldwide. But indoor air pollution is more important from a health perspective. This study measured indoor pollution in a dry laboratory, residential room, and dining hall of a residential academic institute in Mumbai, India. Concentrations of PM₁₀ , PM_2.5 and PM₁ are maximum in window open AC off condition in the laboratory . PM_2.5 concentration, i.e.28.05±15.02 µg/m³ exceeded the WHO prescribed limit for 24 hours. The particle concentration is least in window closed ac on condition. PM₁₀, PM_2.5 and PM₁ concentrations are 8.05±2.54, 7.01±1.05 and 6.49±1.22 µg/m³, respectively, which is 413%, 309%, and 224% lower than window open ac off conditions. The indoor-to-outdoor ratio (I/O) is always less than 1 in this microenvironment, indicating the primary source of indoor particles is the infiltration of particles from outdoors. In the single occupancy residential room, the PM_2.5 concentration violates WHO standards during morning and evening activity (non-cooking/smoking) hours. PM_2.5 is highest in the dining hall adjacent to the kitchen, i.e., 124.62 ±62.24 µg/m³. The I/O is greater than 1 all the time in this microenvironment. The IMPROVE method finds four Organic Carbon (OC) fractions and 3 different elemental carbon (EC) fractions on the quartz fiber filters collected from the microenvironments. All the fractions are lesser in the laboratory environment than corresponding outdoor. But the fractions are higher in the other two indoor microenvironments than the corresponding outdoors. EDXRF was used to figure out the elemental composition. The obtained metal concentrations are used to determine hazard risk (HR) and cancer risks (CR). Surprisingly, the residential room is marginally prone to cancer risk (CR > 1*10^-4) via inhalation; however, no active biomass burning source like cooking and smoking was present there.