10th International Aerosol Conference September 2 - September 7, 2018 America's Center Convention Complex St. Louis, Missouri, USA
Abstract View
Characteristics of Atmospheric Ammonia and Its Relationship with Vehicle Emissions in Shanghai
Ruyu Wang, XINGNAN YE, Fudan University
Abstract Number: 446 Working Group: Air Quality in Megacities: from Sources to Control
Abstract Atmospheric ammonia can not only neutralize sulfate and nitrate to form secondary inorganic aerosols but also favor aqueous oxidation of SO2 and NOx, which plays an important role in haze formation in East China. In this study, long-term measurements of NH3 concentrations were implemented at urban, suburban, and tunnel sites in Shanghai, the largest city in East China. The average monthly ammonia concentrations at the urban site varied from 3.7 ppb to 14.5 ppb and exhibited the highest levels in summer and lowest levels in winter, indicating that the biological emissions and agriculture in the surrounding areas are important contributors. The suburban NH3 levels were significantly higher in autumn compared to those at the urban site, indicating the important contribution of agricultural activities. Regardless of the season, the concentrations of NH3 at the tunnel site remained almost constant. On average, the tunnel NH3 level was three times higher than that of the nearby urban site, indicating strong vehicle NH3 emissions in the tunnel. The tunnel NH3 levels on weekdays were comparable to those on weekends, a result that was in agreement with the daily average traffic volume. It was estimated that the vehicle emissions contributed 12.6-24.6% of the atmospheric NH3 in the urban area of the city and 3.8-7.5% of the total for the whole city. Our results suggest that regulation and control of NH3 emissions from traffic should be considered in order to mitigate severe haze pollution during wintertime in the megacities of China.