Aerosol Chemistry over a High Altitude Station at Northeastern Himalayas, India
Open Access
- 16 June 2010
- journal article
- research article
- Published by Public Library of Science (PLoS) in PLOS ONE
- Vol. 5 (6), e11122
- https://doi.org/10.1371/journal.pone.0011122
Abstract
There is an urgent need for an improved understanding of the sources, distributions and properties of atmospheric aerosol in order to control the atmospheric pollution over northeastern Himalayas where rising anthropogenic interferences from rapid urbanization and development is becoming an increasing concern. An extensive aerosol sampling program was conducted in Darjeeling (altitude ∼2200 meter above sea level (masl), latitude 27°01′N and longitude 88°15′E), a high altitude station in northeastern Himalayas, during January–December 2005. Samples were collected using a respirable dust sampler and a fine dust sampler simultaneously. Ion chromatograph was used to analyze the water soluble ionic species of aerosol. The average concentrations of fine and coarse mode aerosol were found to be 29.5±20.8 µg m−3 and 19.6±11.1 µg m−3 respectively. Fine mode aerosol dominated during dry seasons and coarse mode aerosol dominated during monsoon. Nitrate existed as NH4NO3 in fine mode aerosol during winter and as NaNO3 in coarse mode aerosol during monsoon. Gas phase photochemical oxidation of SO2 during premonsoon and aqueous phase oxidation during winter and postmonsoon were the major pathways for the formation of SO42− in the atmosphere. Long range transport of dust aerosol from arid regions of western India was observed during premonsoon. The acidity of fine mode aerosol was higher in dry seasons compared to monsoon whereas the coarse mode acidity was higher in monsoon compared to dry seasons. Biomass burning, vehicular emissions and dust particles were the major types of aerosol from local and continental regions whereas sea salt particles were the major types of aerosol from marine source regions. The year-long data presented in this paper provide substantial improvements to the heretofore poor knowledge regarding aerosol chemistry over northeastern Himalayas, and should be useful to policy makers in making control strategies.This publication has 37 references indexed in Scilit:
- Enhanced pre‐monsoon warming over the Himalayan‐Gangetic region from 1979 to 2007Geophysical Research Letters, 2009
- Two contrasting dust‐dominant periods over India observed from MODIS and CALIPSO dataGeophysical Research Letters, 2009
- Characteristics of aerosol acidity in Hong KongAtmospheric Environment, 2004
- The importance of carbon and mineral dust to seasonal aerosol properties in the Nepal HimalayaAtmospheric Environment, 2003
- Chemical composition of aerosol and snow in the high Himalaya during the summer monsoon seasonAtmospheric Environment, 1997
- A combined TTFA/CMB receptor modeling approach and its application to air pollution sources in ChinaAtmospheric Environment, 1994
- Measurements of chloride depletion and sulfur enrichment in individual sea‐salt particles collected from the remote marine boundary layerJournal of Geophysical Research: Atmospheres, 1994
- The dissociation constant of ammonium nitrate and its dependence on temperature, relative humidity and particle sizeAtmospheric Environment. Part A. General Topics, 1993
- A chemical characterization of atmospheric aerosol in SapporoAtmospheric Environment. Part A. General Topics, 1990
- ES&T Books: Atmospheric Chemistry and Physics of Air PollutionEnvironmental Science & Technology, 1986