Relative production of ozone and nitrates in urban and rural power plant plumes: 1. Composite results based on data from 10 field measurement days

摘要: A rather limited number of large power plants are responsible for about 2/3 and 1/3 the U.S. anthropogenic emissions SO2 NOx, respectively. Considerable uncertainty continues to prevail local regional impact their potentially harmful secondary products (e.g., ozone, sulfates, nitrates), We have analyzed state-of-the-art data Southern Oxidant Study (SOS)-Nashville Field (1994, 1995) 10 days summer daytime field measurements by instrumented aircraft in plumes three large, tall-stack, base-load, Tennessee Valley Authority (TVA) coal-fired northwestern Tennessee: Gallatin (G), located within Nashville urban ozone nonattainment area, Cumberland (C) Johnsonville (JV) rural isoprene-rich forested areas 100 km west Nashville. The average 1995 NOx from these sources ranged over more than an order magnitude. In this paper, we explored plume chemical evolution magnitude, efficiency, yield NOz, (NOx oxidation products, mostly inorganic organic nitrates) production a broad variety transport chemistry scenarios convective boundary layer (CBL) settings. results show that (1) maturity peak capacities NOz were realized quite close sources, 30–40 4 hours (smallest emission rate, QNOx, suburban environment) typically 6 CBL (highest QNOx environment rich isoprene); (2) on can exceed Cumberland, under favorable conditions, both contribute as much 50 ppb excess raising levels well ppb; (3) estimated 3.1±0.7 molecules 0.6 may be produced isolated plant (PPPs) per molecule release, corresponding yields significantly greater PPPs; (4) rate ≈ 10–15% h−1 PPPs, higher (5) is favored all PPPs at first when VOC-limited; later, with increasing VOC ingestion background, increasingly favors NOx-limited production, starting edges, ultimately throughout diluted plume. These major implications outstanding issues related environmental regulatory control electric utility industry emissions.