AAAR 33rd Annual Conference
October 20 - October 24, 2014
Rosen Shingle Creek
Orlando, Florida, USA
Abstract View
Elemental and Individual Particle Analysis of Atmospheric Aerosols from New Delhi, India
HONGRU SHEN, Thomas Peters, Gary Casuccio, Naresh Kumar, Andrew Ault, University of Michigan
Abstract Number: 151 Working Group: Source Apportionment
Abstract The Indian capital, New Delhi, is one of the most polluted cities with respect to particulate matter. Deaths due to respiratory disease are now second only to cardiovascular disease and without a concerted effort this condition will only worsen. However, few particulate matter studies conducted in New Delhi have focused on individual atmospheric particles, with most studies confined to bulk particles analysis. The lack of such studies in New Delhi has motivated this work investigating the particle sources and processing in the atmosphere. Atmospheric particles were passively sampled at 50 sites across New Delhi, in October through December 2008. These samples were analyzed using computer controlled scanning electron microscopy (CCSEM) to determine the physical (size and morphology) and chemical properties (energy dispersive spectrometry (EDS) of 18 elements) of individual particles. The particles analyzed in the study were primarily < 10 µm, with most < 2.5 µm. All sample particles were classified into distinct groups, using the k-means clustering algorithm on the EDS spectra. The predominant particle types were mineral dust, different types of fly ash, and lead-rich particles. The main sources of anthropogenic particles are likely motor vehicle traffic, domestic fuel burning, industrial sources, and power plants. Lead-rich particles were distributed heterogeneously among the sites, and identification of the precise source, likely combustion of leaded fuel, is ongoing. Future studies will focus on characterizing the physical properties of the different types of particles spatially to determine sources, atmospheric history, reactivity, and transport. This detailed single particle identification of sources and spatiotemporal trends can be used as part of future efforts to evaluate particulate matter exposure city-wide in New Delhi.