AAAR 36th Annual Conference October 16 - October 20, 2017 Raleigh Convention Center Raleigh, North Carolina, USA
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Preliminary Assessment of Aerosol Associated Organic Tracers in Rural and Urban Location of Western Himalayas
SHWETA YADAV, Deepika Kaushal, Sarita Bamotra, Ankit Tandon, Central University of Jammu, Samba, Jammu, India
Abstract Number: 445 Working Group: Carbonaceous Aerosols in the Atmosphere
Abstract The Himalayan region with its unique location acts as a climate regulator in South-East Asia. Keeping in mind the limited knowledge about the sources and composition of organic aerosols in this region, aerosol associated organic tracers: n-alkanes, Polycyclic Aromatic Hydrocarbons (PAHs), Isoprenoid hydrocarbons, particulate bound nicotine, levoglucosan and isoquinoline have been investigated in PM10 samples collected in rural and urban locations of Western Himalayas. The aerosol sampling was conducted from January 2015 to December, 2015. The analysis of monthly representative aerosol samples was done using Thermal Desorption Gas Chromatography Mass Spectrometry (TD-GCMS). Established organic markers, associated diagnostic parameters, and molecular diagnostic ratios were used to assess and discern the contributing biogenic, petrogenic and pyrogenic sources in the region. The n-alkane based diagnostic parameters include—mass weighted Averaged Chain Length (ACL); Carbon number with maximum concentration (Cmax); Petroleum derived n-alkanes (PNA%), Carbon Preference Index (CPI) and the percentage contribution of Wax n-alkanes from plants (WNA%). The average value of ACL at rural and urban location is 29 ± 0.86 and 30 ± 1.15 respectively. A significant predominance of high molecular weight congeners C29, C30 and C31 indicates contributions from leaf plant wax and other mixed sources like road dust, garden soil, cooking oil and cigarette smoke. Irrespective of the difference in altitude and land use pattern, CPI and WNA% clearly indicated the predominance of petrogenic sources in both the locations with an exception of biogenic spurts (CPI>1) at rural location in the harvesting season. Strong seasonal variations were noticed in determined n-alkanes, isoprenoid hydrocarbons, selected PAHs and markers like Levoglucosan. Particulate bound Tracers for Environment Tobacco Smoke (ETS) like nicotine were noticed in all the samples and the high values raise serious concerns.