OPEN ACCESS

Articles online

Atmospheric Abundances of Nitrogen Species in Rain and Aerosols Over a Semi-Arid Region: Sources and Deposition Fluxes

Category: Articles

Volume: 6 | Issue: 4 | Pages: 406-417
DOI: 10.4209/aaqr.2006.07.0008
PDF | RIS | BibTeX

Neeraj Rastogi, Manmohan Sarin

  • Physical Research Laboratory, Ahmedabad-380 009, India

Abstract

The temporal variation for a three-year period (2000-2002) in the atmospheric abundances of principal nitrogen species (NH4+ and NO3-) has been studied in rain and aerosols from an urban city (Ahmedabad, 23.0°N, 72.6°E) located in a semi-arid region of western India. Their concentrations in ambient aerosols over the annual seasonal cycle exhibit large variation [NH4+: < 0.001 to 1.3 (GM = 0.25 μg/m3); NO3-: 0.09 to 4.4 (GM = 1.3 μg/m3)]; with systematically higher concentrations during Nov-Feb (drier period) and relatively low during Jun-Aug (wet season). In comparison, abundances of NH4+ and NO3- in individual precipitation events (n = 91) collected during the southwest monsoon (Jun-Aug) for three years varied as NH4+: 3-: 1.3 to 115 (VWM: 13 μeq/L). Using corresponding rainfall data, the wet-deposition fluxes of NH4+ during 2000, 2001 and 2002 have been derived: 364, 327 and 297 mg/m2/y, respectively; which are considerably higher than the dry-deposition fluxes (16, 11 and 16 mg/m2/y). The wet deposition of NO3- over the three years varied as 392, 569 and 487 mg/m2/y in comparison to dry-deposition fluxes averaging as 201, 134 and 137 mg /m2/y. These results also indicate that both dry and wet deposition of NO3- accounts for as much as ~65% of the total inorganic-N species (NH4+ + NO3-), possibly mediated via in-situ chemical reactions of acidic species (NO3- and its precursors) with mineral aerosols. Such regional scale studies are important for quantitative assessment of atmospheric deposition of biogeochemically important trace species and bring to focus the role of semi-arid regions where current knowledge is limited.

Keywords

Dry and wet deposition NH4+ NO3- Aerosol Precipitation Semi-arid region India


Related Article

Critical Emissions from the Largest On-Road Transport Network in South Asia

Saroj Kumar Sahu , Gufran Beig, Neha Parkhi
Volume: 14 | Issue: 1 | Pages: 135-144
DOI: 10.4209/aaqr.2013.04.0137
PDF

Ambient Air Quality during Diwali Festival over Kolkata – A Mega-City in India

A. Chatterjee , C. Sarkar, A. Adak, U. Mukherjee, S.K. Ghosh, S. Raha
Volume: 13 | Issue: 3 | Pages: 1133-1144
DOI: 10.4209/aaqr.2012.03.0062
PDF

Exploring the Variation between EC and BC in a Variety of Locations

Gbenga Oladoyin Salako, Philip K. Hopke , David D. Cohen, Bilkis A. Begum, Swapan K. Biswas, Gauri Girish Pandit, Yong-Sam Chung, Shamsiah Abd Rahman, Mohd Suhaimi Hamzah, Perry Davy, Andreas Markwitz, Dagva Shagjjamba, Sereeter Lodoysamba, Wanna Wimolwattanapun, Supamatthree Bunprapob
Volume: 12 | Issue: 1 | Pages: 1-7
DOI: 10.4209/aaqr.2011.09.0150
PDF
;