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Summary: Chemical coupling between ammonia, acid gases, and fine particles
Bok Haeng Baek, Viney P. Aneja*, Quansong Tong
Department of Marine, Earth, and Atmospheric Sciences, North Carolina State University, Raleigh, NC 27695, USA
Received 29 May 2001; accepted 25 September 2003
``Capsule'': Our study of ammonia, acid gases, and fine particles provided a gas-to-particle conversion process that
improved prediction of long-range transport of pollutants, air quality, and climate change.
Abstract
The concentrations of inorganic aerosol components in the fine particulate matter (PMfine42.5 mm) consisted of primarily
ammonium, sodium, sulfate, nitrate, and chloride are related to the transfer time scale between gas to particle phase, which is a
function of the ambient temperature, relative humidity, and their gas phase constituent concentrations in the atmosphere. This
study involved understanding the magnitude of major ammonia sources; and an up-wind and down-wind (receptor) ammonia, acid
gases, and fine particulate measurements; with a view to accretion gas-to-particle conversion (GTPS) process in an agricultural/
rural environment. The observational based analysis of ammonia, acid gases, and fine particles by annular denuder system (ADS)
coupled with a Gaussian dispersion model provided the mean pseudo-first-order kS-1 between NH3 and H2SO4 aerosol $5.00
(Æ3.77)Â10À3
sÀ1
. The rate constant was found to increase as ambient temperature, wind speed, and solar radiation increases, and
decreases with increasing relative humidity. The observed [NH3][HNO3] products exceeded values predicted by theoretical equili-
brium constants, due to a local excess of ammonia concentration.
# 2003 Elsevier Ltd. All rights reserved.
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