Impacts of additional HONO sources on concentrations and deposition of NOy in the Beijing-Tianjin-Hebei Region of China

Abstract

This study applies the chemistry version of the Weather Research and Forecasting model (WRF-Chem) to examine impacts of three additional HONO sources, i.e., the reaction of photoexcited NO2 (NO2 *) with water vapor (NO2 * chemistry), the NO2 heterogeneous reaction on aerosol surfaces and HONO emissions, on concentrations and deposition of individual NOy species over the Beijing-Tianjin-Hebei region (BTH) in summer and winter periods of 2007. The results show that the three additional HONO sources produce a 20%~40% ( > 100%) increase in monthly-mean OH concentrations in many urban areas in August (February), leading to a 10%~40% (10%~100%) variation in monthly-mean concentrations of NOx, NO3 - and PAN, a 5%~10% (10%~40%) increase in the total dry deposition of NOy, and an enhancement of 1.4 Gg N (1.5 Gg N) in the total of dry and wet deposition of NOy over this region in August (February). These results suggest that the additional HONO sources aggravate regional-scale acid deposition, emphasizing the importance of the additional HONO sources in the NOy budget.