Impact Assessment of Ammonia Emissions on Inorganic Aerosols in East China Using Response Surface Modeling Technique

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• 作者：Shuxiao Wang ; Jia Xing ; Carey Jang ; Yun Zhu ; Joshua S. Fu ; Jiming Hao
• 刊名：Environmental Science & Technology
• 出版年：2011
• 出版时间：November 1, 2011
• 年：2011
• 卷：45
• 期：21
• 页码：9293-9300
• 全文大小：1152K
• 年卷期：v.45,no.21(November 1, 2011)
• ISSN：1520-5851

文摘

Ammonia (NH₃) is one important precursor of inorganic fine particles; however, knowledge of the impacts of NH₃ emissions on aerosol formation in China is very limited. In this study, we have developed China鈥檚 NH₃ emission inventory for 2005 and applied the Response Surface Modeling (RSM) technique upon a widely used regional air quality model, the Community Multi-Scale Air Quality Model (CMAQ). The purpose was to analyze the impacts of NH₃ emissions on fine particles for January, April, July, and October over east China, especially those most developed regions including the North China Plain (NCP), Yangtze River delta (YRD), and the Pearl River delta (PRD). The results indicate that NH₃ emissions contribute to 8鈥?1% of PM_2.5 concentrations in these three regions, comparable with the contributions of SO₂ (9鈥?1%) and NO_x (5鈥?1%) emissions. However, NH₃, SO₂, and NO_x emissions present significant nonlinear impacts; the PM_2.5 responses to their emissions increase when more control efforts are taken mainly because of the transition between NH₃-rich and NH₃-poor conditions. Nitrate aerosol (NO₃^{鈥?/sup>) concentration is more sensitive to NO_x emissions in NCP and YRD because of the abundant NH₃ emissions in the two regions, but it is equally or even more sensitive to NH₃ emissions in the PRD. In high NO₃鈥?/sup> pollution areas such as NCP and YRD, NH₃ is sufficiently abundant to neutralize extra nitric acid produced by an additional 25% of NO_x emissions. The 90% increase of NH₃ emissions during 1990鈥?005 resulted in about 50鈥?0% increases of NO₃鈥?/sup> and SO₄2- aerosol concentrations. If no control measures are taken for NH₃ emissions, NO₃鈥?/sup> will be further enhanced in the future. Control of NH₃ emissions in winter, spring, and fall will benefit PM_2.5 reduction for most regions. However, to improve regional air quality and avoid exacerbating the acidity of aerosols, a more effective pathway is to adopt a multipollutant strategy to control NH₃ emissions in parallel with current SO₂ and NO_x controls in China.}