Abstract View
Intra and Inter-Urban Variability in Carbonaceous Components of Fine Particulate Matter in Metropolitan Cities in India
PRINCE VIJAY, Shreya Dubey, Harish C Phuleria, Indian Institute of Technology Bombay
Abstract Number: 175
Working Group: Urban Aerosols
Abstract
Fine particulate matter (PM2.5) is the most critical criteria air pollutant in India and exceeds the regulatory limit in a majority of the metropolitan and class 1 cities across India and thus poses an important public health concern. In the present study, aim was to examine the seasonal variation of outdoor PM2.5 and its chemical constituents in urban residential background locations in three metropolitan cities. Residential outdoor 24-hour averaged PM2.5 was collected from three neighbourhoods, representing traffic, residential and industrial areas, in three metropolitan cities - Mumbai, Bengaluru and Delhi. The measurements were conducted at all locations for two weeks in two distinct seasons. Collected PM2.5 samples were examined for trace metals and elements, elemental and organic carbon and inorganic ions using standard analytical methods. Average PM2.5 during the winter was 121.6±31.1, 75.2±33.4 and 195.3±68.8 µg/m3 for Mumbai, Bengaluru and Delhi, respectively, exhibiting significant differences among the cities (p<<<0.05). PM2.5 levels in Mumbai were significantly lower (63.2±24.4 µg/m3) during the summer (p<0.05). Weekday to weekend differences were not significant in Mumbai and Bangalore (p>0.05) but noticeable in Delhi (p<0.05). Black carbon (BC) was 1.9±0.3, 1.1±0.3 and 2.1±0.7 µg/m3 for the three cities, respectively representing ~1% of mass. However, significant differences were not observed among the neighborhoods in the cities for both the pollutants. Water-soluble organic carbon (WSOC) was 8.5±2.3 during winter (6.5% of the PM2.5) and 3.5±2.8 µg/m3 during summer (2.7%) in Mumbai. Organic and elemental carbon concentrations in Mumbai during the summer were 11.2±2.7 and 1.3±0.4 µg/m3, respectively. WSOC/OC ratios (0.1 for traffic, 0.2 for residential, and 0.6 for industrial locations) suggest the varying nature of OC at different locations in Mumbai and the differential impact of primary and secondary sources. Further chemical characterization of Delhi and Bengaluru samples and assessment of within city variation in chemical composition is underway.