Status: this preprint was under review for the journal ACP but the revision was not accepted.
Impact of nitrous acid chemistry on air quality modeling results over the Pearl River Delta region
R. Zhang,G. Sarwar,J. C. H. Fung,A. K. H. Lau,and Y. Zhang
Abstract. The impact of nitrous acid chemistry on regional ozone and particulate matter in Pearl River Delta region was investigated using the Community Mutilscale Air Quality modeling system and the CB05 mechanism. Model simulations were conducted for a ten-day period in October 2004. Compared with available observed data, the model performance for NOx, SO2, PM10, and sulfate is reasonably good; however, predictions of HONO are an order of magnitude lower than observed data. The CB05 mechanism contains several homogenous reactions related to nitrous acid. To improve the model performance for nitrous acid, direct emissions, two heterogeneous reactions, and two surface photolysis reactions were incorporated into the model. The inclusion of the additional formation pathways significantly improved simulated nitrous acid compared with observed data. The addition of nitrous acid sources enhance daily maximum 8-h ozone by up to 6 ppb V (8 %) and daily mean PM2.5 by up to 17 μg m−3 (12 %). They also affected ozone control strategy in Pearl River Delta region.
Received: 23 Mar 2011 – Discussion started: 18 May 2011
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Department of Mathematics, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China
G. Sarwar
Atmospheric Modeling and Analysis Division, National Exposure Research Laboratory, Office of Research and Development, US Environmental Protection Agency, RTP, NC 27711, USA
J. C. H. Fung
Department of Mathematics, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China
Division of Environment, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China
A. K. H. Lau
Division of Environment, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China
Y. Zhang
College of Environmental Sciences and Engineering, Peking University, Beijing, 100871, China