Sensitivity of Nitrate Aerosol Production to Vehicular Emissions in an Urban Street

Atmosphere

MinjoongJ. Kim¹ 

[1] Department of Environmental Engineering and Energy, Myongji University, Yongin 17058, Gyunggi, Korea;

关键词: Urban pollution;    Street canyon;    Nitrate aerosol;    CFD;    Air quality;   

DOI  :  10.3390/atmos10040212

来源: DOAJ

【 摘 要 】

This study investigated the sensitivity of nitrate aerosols to vehicular emissions in urban streets using a coupled computational fluid dynamics (CFD)–chemistry model. Nitrate concentrations were highest at the street surface level following NH₃ emissions from vehicles, indicating that ammonium nitrate formation occurs under NH₃-limited conditions in street canyons. Sensitivity simulations revealed that the nitrate concentration has no clear relationship with the NO_x emission rate, showing nitrate changes of only 2% across among 16 time differences in NO_x emissions. NO_x emissions show a conflicting effect on nitrate production via decreasing O₃ and increasing NO₂ concentrations under a volatile organic compound (VOC)-limited regime for O₃ production. The sensitivity simulations also show that nitrate aerosol is proportional to vehicular VOC and NH₃ emissions in the street canyon. Changes of VOC emissions affect the nitrate aerosol and HNO₃ concentrations through changes in the O₃ concentration under a VOC-limited regime for O₃ production. Nitrate aerosol concentration is influenced by vehicular NH₃ emissions, which produce ammonium nitrate effectively under an NH₃-limited regime for nitrate production. This research suggests that, when vehicular emissions are dominant in winter, the control of vehicular VOC and NH₃ emissions might be a more effective way to degrade PM_2.5 problems than the control of NO_x.

【 授权许可】

Unknown