Contribution of nitrous acid (HONO) sources to atmospheric HONO concentration in chemistry transport model : Case study of the KORUS-AQ campaign

Abstract

The atmospheric HONO has important role in atmosphere as a precursor of OH, HO2, and O3. And it is produced and sink with various sources. For example, NOx from soil bacteria activity in wet soil converted to HONO with specific ratio. Also combustion processes of engine in transportation emits HONO into the atmosphere. In addition, chemical reactions are important sources and sink of atmospheric HONO. In the atmosphere, gas-phase reactions, heterogeneous reactions on ground and aerosol surfaces, and photolysis reactions of HONO exists. These sources and sinks affect to atmospheric HONO concentration. So it is important to figure out contribution of each sources to atmospheric concentration. In conventional Chemistry Transport Model (CTM), only four gas-phase reactions and heterogeneous reactions are included. In this study, four main sources of HONO were added into Community Multi-Scale Air Quality (CMAQ) model one of the CTM and the contribution of each HONO sources were analyzed with simulated results of CMAQ. The analysis period and observation data is from the Korea-United States Air Quality (KORUS-AQ) campaign at May and June of 2016. Also Korean Flexible Chemistry(KFC) editor was used for edit chemical reactions in CMAQ model and SAPRC07tc mechanisms. The contribution of each sources were analyzed at four different region, Olympic park, Taehwa Rearch Forest(TRF), and averaged for whole South Korea and China.