Wang M Y, Yim Steve H L, Dong G H, Ho K F, Wong D C
Department of Geography and Resource Management, The Chinese University of Hong Kong, Sha Tin, N.T., Hong Kong, China.
Institute of Environment, Energy and Sustainability, The Chinese University of Hong Kong, Sha Tin, N.T., Hong Kong, China.
Atmos Environ (1994). 2020 Feb 1;222:1-117026. doi: 10.1016/j.atmosenv.2019.117026.
While fine particulate matters are decreasing in the Pearl River Delta (PRD) region, the regional ozone (O) shows an increasing trend that affects human health, leading to an urgent need for scientific understanding of source-receptor relationship between O and its precursor emissions given the changing background composition. We advanced and applied an adjoint air quality model to map contributions of individual O precursor emission sources [nitrogen oxides (NO) and volatile organic compound (VOC)] at each location to annual regional O concentrations and to identify the possible dominant influential pathways of emission sources to O at different spatiotemporal scales. Additionally, we introduced the novel adjoint sensitivity approach to assess the relationship between precursor emissions and O-induced premature mortality. Adjoint results show that Shenzhen was a major source contributor to regional O throughout all seasons, of which 49.4% (3.8%) were from its NO (VOC) emissions. Local emissions (within PRD) contributed to 83% of the regional O whereas only ~54% of the estimated ~4000 regional O-induced premature mortalities. The discrepancy between these two contributions was because O-induced mortalities are dependent on not only O concentration, but incident rate and population density. We also found that a city with low O-induced mortalities could have significant emission contributions to health impact in the region since the transport pathways could be through transport of local O or through transport of O precursors that form regional O thereafter. It is therefore necessary to formulate emission control policies from both air quality and public health perspectives, and it is also critical to have better understanding of influential pathways of emission sources to O.
虽然珠江三角洲（PRD）地区的细颗粒物在减少，但区域臭氧（O₃）呈上升趋势，影响人类健康。鉴于背景成分不断变化，迫切需要科学了解O₃与其前体排放之间的源-受体关系。我们改进并应用了伴随空气质量模型，以绘制每个地点的单个O₃前体排放源[氮氧化物（NOₓ）和挥发性有机化合物（VOC）]对年度区域O₃浓度的贡献，并确定排放源在不同时空尺度上对O₃可能的主要影响途径。此外，我们引入了新颖的伴随敏感性方法来评估前体排放与O₃导致的过早死亡之间的关系。伴随结果表明，深圳是全年区域O₃的主要排放源贡献地，其中49.4%（3.8%）来自其NOₓ（VOC）排放。珠三角地区内的本地排放对区域O₃的贡献率为83%，而在估计的约4000例区域O₃导致的过早死亡中，本地排放的贡献率仅约为54%。这两种贡献之间的差异是因为O₃导致的死亡不仅取决于O₃浓度，还取决于发病率和人口密度。我们还发现，一个O₃导致死亡率较低的城市可能对该地区的健康影响有重大排放贡献，因为传输途径可能是通过本地O₃的传输，或者是通过O₃前体的传输，这些前体随后形成区域O₃。因此，有必要从空气质量和公共卫生角度制定排放控制政策，更好地了解排放源对O₃的影响途径也至关重要。
