Chemical coupling between ammonia, acid gases, and fine particles

摘要

The concentrations of inorganic aerosol components in the fine particulate matter (PM_(fine)≤2.5 μm) 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 k_(S-1) between NH_3 and H_2SO_4 aerosol ～5.00 (+-3.77)x10~(-3) s~(-1). The rate constant was found to increase as ambient temperature, wind speed, and solar radiation increases, and decreases with increasing relative humidity. The observed [NH_3][HNO_3] products exceeded values predicted by theoretical equilibrium constants, due to a local excess of ammonia concentration.