上海夏季臭氧生成机制时空变化特征及其影响因素研究
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摘要
上海的臭氧污染呈逐年加重的趋势,深入了解臭氧的生成机制及其时空变化特征是采取科学有效防控措施的前提条件.本研究应用长三角地区最新的臭氧前体物排放清单和本地化WRF/Modified SMOKE/CMAQ数值模型系统,对2017年8月1—9日上海市一次持续性臭氧污染事件进行了模拟研究.同时,在重现臭氧浓度变化趋势的基础上,针对一系列前体物防控措施及其对臭氧峰值浓度的影响开展了敏感性实验,建立了上海夏季臭氧污染爆发时段各区域臭氧及其前体物的非线性响应关系.研究表明,此次臭氧污染事件中上海市臭氧污染机制具有显著的时空变化特征,时间方面,上海市整体臭氧生成机制由NO_x控制经过渡区转变为VOCs控制;空间方面,上海北部及西部多处于NO_x控制,南部为过渡区,中部及东部则以VOCs控制为主,且大尺度环流是导致其时空变化的主要原因.当上海受大陆低压控制盛行偏南风时,区域传输以VOCs为主,臭氧的防控应侧重于NO_x减排;当上海受副高边缘控制主要吹偏北风时,区域传输以NO_x为主,臭氧的防控应侧重于VOCs减排;当上海受弱高压脊控制背景风微弱,区域传输不显著时,臭氧防控的重点应以VOCs和NO_x协同控制为主.在目前的预报技术下,大尺度环流特征通常可以提前48～72 h进行准确预报,因此,可以根据大尺度环流预报结果及时调整本地防控策略,以达到在不同污染特征下臭氧削峰的最大化效果.
The ozone pollution in Shanghai is becoming serious in recent years. In-depth understanding of ozone formation mechanism and its spatio-temporal variation is the pre-requisite of formulating effective control measures. This study applied the latest ozone precursor emission inventory in the Yangtze River Delta(YRD) and the localized WRF/Modified SMOKE/CMAQ numerical modeling system to simulate a continuous ozone pollution event in Shanghai during 1—9 August 2017. By replicating the temporal variation of ozone concentration, a series of sensitivity study with different precursor reduction degrees was conducted to establish the non-linear relationship between ozone and its precursors during pollution episodes. It was found that the ozone formation mechanism in Shanghai displayed significant spatio-temporal variations. Temporally, the overall ozone formation mechanism in Shanghai transformed from NO_x-limited to transitional regime then to VOCs-limited. Spatially, the northern and western area was under NO_x-limited, southern area was in transitional regime, while central and eastern area was more dominated by VOCs-limited. The large-scale circulation pattern played an important role in this spatio-temporal variation. When Shanghai was controlled by a continental low with prevailing southerly wind, VOCs was enriched in the transport air mass and local control should target on NO_x emission reduction; when Shanghai was controlled by western Pacific subtropical high with prevailing northerly wind, NO_x was enriched in the transport air mass and local control should target on VOCs emission reduction; when Shanghai was controlled by weak high-pressure ridge with weak background wind and regional transport, local control should target on VOCs/NO_x synergistic reduction. With the current forecast capability, the large-scale circulation pattern can be forecasted with good accuracy by 48～72 hours. Therefore, local control focus should be dynamically adjusted according to the large-scale circulation forecast, so as to maximize the ozone despiking efficiency under different pollution conditions.
The ozone pollution in Shanghai is becoming serious in recent years. In-depth understanding of ozone formation mechanism and its spatio-temporal variation is the pre-requisite of formulating effective control measures. This study applied the latest ozone precursor emission inventory in the Yangtze River Delta(YRD) and the localized WRF/Modified SMOKE/CMAQ numerical modeling system to simulate a continuous ozone pollution event in Shanghai during 1—9 August 2017. By replicating the temporal variation of ozone concentration, a series of sensitivity study with different precursor reduction degrees was conducted to establish the non-linear relationship between ozone and its precursors during pollution episodes. It was found that the ozone formation mechanism in Shanghai displayed significant spatio-temporal variations. Temporally, the overall ozone formation mechanism in Shanghai transformed from NO_x-limited to transitional regime then to VOCs-limited. Spatially, the northern and western area was under NO_x-limited, southern area was in transitional regime, while central and eastern area was more dominated by VOCs-limited. The large-scale circulation pattern played an important role in this spatio-temporal variation. When Shanghai was controlled by a continental low with prevailing southerly wind, VOCs was enriched in the transport air mass and local control should target on NO_x emission reduction; when Shanghai was controlled by western Pacific subtropical high with prevailing northerly wind, NO_x was enriched in the transport air mass and local control should target on VOCs emission reduction; when Shanghai was controlled by weak high-pressure ridge with weak background wind and regional transport, local control should target on VOCs/NO_x synergistic reduction. With the current forecast capability, the large-scale circulation pattern can be forecasted with good accuracy by 48～72 hours. Therefore, local control focus should be dynamically adjusted according to the large-scale circulation forecast, so as to maximize the ozone despiking efficiency under different pollution conditions.
引文
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Kinosian J R.1982.Ozone-precursor relationships from EKMA diagrams[J].Environmental Science & Technology,16:880-883
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Li Q,Zhang L,Wang T,et al.2018."New" reactive nitrogen chemistry reshapes the relationship of ozone to its precursors[J].Environmental Science & Technology,52(5),DOI:10.1021/acs.est.7b05771
Li Y,Lau K H,Fung J,et al.2013.Importance of NOx control for peak ozone reduction in the Pearl River Delta region[J].Journal of Geophysical Research Atmospheres,118(16):9428-9443
Liao Z,Gao M,Sun J,et al.2017.The impact of synoptic circulation on air quality and pollution-related human health in the Yangtze River Delta region[J].Science of the Total Environment,607-608:838-846
李泽琨.2015.珠江三角洲地区臭氧及其前体物非线性响应特征及控制对策研究[D].广州:华南理工大学
Madronich S.2014.Ethanol and ozone[J].Nature Geoscience,7(6):395-397
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Pan S,Choi Y,Roy A,et al.2017.Allocating emissions to 4 km and 1 km horizontal spatial resolutions and its impact on simulated NOx and O3 in Houston,TX[J].Atmospheric Environment,164:398-415
Solomon P,Cowling E,Hidy G,et al.2000.Comparison of scientific findings from major ozone field studies in North America and Europe[J].Atmospheric Environment,34(12/14):1885-1920
上海市统计局.2017.上海市统计年鉴2017[M].北京:中国统计出版社
Tie X,Geng F,Guenther A,et al.2013.Megacity impacts on regional ozone formation:observations and WRF-Chem modeling for the MIRAGE-Shanghai field campaign[J].Atmospheric Chemistry & Physics,13(11):5655-5669
Wang S S,Zheng J Y,Fu F,et al.2011.Development of an emission processing system for the Pearl River Delta Regional air quality modeling using the SMOKE model:Methodology and evaluation[J].Atmospheric Environment,45(29):5079-5089
王水胜.2012.基于数值模拟的珠江三角洲及周边城市氮沉降特征研究[D].广州:华南理工大学
Wang T,Xue L K,Brimblecombe P,et al.2016.Ozone pollution in China:A review of concentrations,meteorological influences,chemical precursors,and effects[J].Science of the Total Environment,575:1582-1596
Wang X S,Zhang Y H,Hu Y T,et al.2011.Decoupled direct sensitivity analysis of regional ozone pollution over the Pearl River Delta during the PRIDE-PRD2004 campaign[J].Atmospheric Environment,45(28):4941-4949
Wu R, Xie S.2017.Spatial distribution of ozone formation in China derived from emissions of speciated volatile organic compounds[J].Environmental Science & Technology,51(5):2574
Xu Z G,Huang X,Nie W,et al.2017.Influence of synoptic condition and holiday effects on VOCs and ozone production in the Yangtze River Delta region,China[J].Atmospheric Environment,DOI: 10.1016/j.atmosenv.2017.08.035
Yang Y D,Shao M,Wang X M,et al.2016.Towards a quantitative understanding of total OH reactivity:A review[J].Atmospheric Environment,134:147-161
Zhang Y,Cheng S H,Chen Y S,et al.2011.Application of MM5 in China:Model evaluation,seasonal variations,and sensitivity to horizontal grid resolutions[J].Atmospheric Environment,45(20):3454-3465
Zheng C H,Shen J L,Zhang Y X,et al.2017.Atmospheric emission characteristics and control policies of anthropogenic VOCs from industrial sources in Yangtze River Delta Region,China[J].Aerosol & Air Quality Research,17
中华人民共和国生态环境部.2017.中国环境年报2017[R].北京:中华人民共和国生态环境部
Chen D,Wang X,Li Y,et al.2017.High-spatiotemporal-resolution ship emission inventory of China based on AIS data in 2014[J].Science of the Total Environment,609:776-787
Fujita E M,Campbell D E,Stockwell W R,et al.2013.Past and future ozone trends in California′s South Coast Air Basin:reconciliation of ambient measurements with past and projected emission inventories[J].Journal of the Air & Waste Management Association,63(1):54-69
Geng F H,Tie X X,Xu J M,et al.2008.Characterizations of ozone,NOx,and VOCs measured in Shanghai,China[J].Atmospheric Environment,42(29):6873-6883
Geng F H,Zhao C S,Tang X,et al.2007.Analysis of ozone and VOCs measured in Shanghai:A case study[J].Atmospheric Environment,41(5):989-1001
Hidy G M.2000.Ozone process insights from field experiments-part I:overview[J].Atmospheric Environment,34(12/14):2001-2022
Huang C,Chen C H,Li L,et al.2011.Emission inventory of anthropogenic air pollutants and VOC species in the Yangtze River Delta region,China[J].Atmospheric Chemistry & Physics,11(9):4105-4120
Jenkin M E, Clemitshaw K C.2002.Chapter 11 ozone and other secondary photochemical pollutants:chemical processes governing their formation in the planetary boundary layer[J].Atmospheric Environment,1(16):285-338
Kinosian J R.1982.Ozone-precursor relationships from EKMA diagrams[J].Environmental Science & Technology,16:880-883
Li K W,Chen L H,Ying F,et al.2017.Meteorological and chemical impacts on ozone formation:A case study in Hangzhou,China[J].Atmospheric Research,196
Li Q,Zhang L,Wang T,et al.2018."New" reactive nitrogen chemistry reshapes the relationship of ozone to its precursors[J].Environmental Science & Technology,52(5),DOI:10.1021/acs.est.7b05771
Li Y,Lau K H,Fung J,et al.2013.Importance of NOx control for peak ozone reduction in the Pearl River Delta region[J].Journal of Geophysical Research Atmospheres,118(16):9428-9443
Liao Z,Gao M,Sun J,et al.2017.The impact of synoptic circulation on air quality and pollution-related human health in the Yangtze River Delta region[J].Science of the Total Environment,607-608:838-846
李泽琨.2015.珠江三角洲地区臭氧及其前体物非线性响应特征及控制对策研究[D].广州:华南理工大学
Madronich S.2014.Ethanol and ozone[J].Nature Geoscience,7(6):395-397
Mo Z,Shao M,Lu S,et al.2015.Process-specific emission characteristics of volatile organic compounds (VOCs) from petrochemical facilities in the Yangtze River Delta,China[J].Science of the Total Environment,533(2):422-431
NARSfTOS(North American Research Strategy for Tropospheric Ozone Synthesis Team).2000.Assessment of tropospheric ozone pollution:a North American perspective[OL].2000-07-01.http://www.cgenv.com/Narsto/ home.html.
Ou J M,Yuan Z B,Zheng J Y,et al.2016.Ambient ozone control in a photochemically active region:short-term despiking or long-term attainment?[J] Environmental Science & Technology,50(11):5720
Pan S,Choi Y,Roy A,et al.2017.Allocating emissions to 4 km and 1 km horizontal spatial resolutions and its impact on simulated NOx and O3 in Houston,TX[J].Atmospheric Environment,164:398-415
Solomon P,Cowling E,Hidy G,et al.2000.Comparison of scientific findings from major ozone field studies in North America and Europe[J].Atmospheric Environment,34(12/14):1885-1920
上海市统计局.2017.上海市统计年鉴2017[M].北京:中国统计出版社
Tie X,Geng F,Guenther A,et al.2013.Megacity impacts on regional ozone formation:observations and WRF-Chem modeling for the MIRAGE-Shanghai field campaign[J].Atmospheric Chemistry & Physics,13(11):5655-5669
Wang S S,Zheng J Y,Fu F,et al.2011.Development of an emission processing system for the Pearl River Delta Regional air quality modeling using the SMOKE model:Methodology and evaluation[J].Atmospheric Environment,45(29):5079-5089
王水胜.2012.基于数值模拟的珠江三角洲及周边城市氮沉降特征研究[D].广州:华南理工大学
Wang T,Xue L K,Brimblecombe P,et al.2016.Ozone pollution in China:A review of concentrations,meteorological influences,chemical precursors,and effects[J].Science of the Total Environment,575:1582-1596
Wang X S,Zhang Y H,Hu Y T,et al.2011.Decoupled direct sensitivity analysis of regional ozone pollution over the Pearl River Delta during the PRIDE-PRD2004 campaign[J].Atmospheric Environment,45(28):4941-4949
Wu R, Xie S.2017.Spatial distribution of ozone formation in China derived from emissions of speciated volatile organic compounds[J].Environmental Science & Technology,51(5):2574
Xu Z G,Huang X,Nie W,et al.2017.Influence of synoptic condition and holiday effects on VOCs and ozone production in the Yangtze River Delta region,China[J].Atmospheric Environment,DOI: 10.1016/j.atmosenv.2017.08.035
Yang Y D,Shao M,Wang X M,et al.2016.Towards a quantitative understanding of total OH reactivity:A review[J].Atmospheric Environment,134:147-161
Zhang Y,Cheng S H,Chen Y S,et al.2011.Application of MM5 in China:Model evaluation,seasonal variations,and sensitivity to horizontal grid resolutions[J].Atmospheric Environment,45(20):3454-3465
Zheng C H,Shen J L,Zhang Y X,et al.2017.Atmospheric emission characteristics and control policies of anthropogenic VOCs from industrial sources in Yangtze River Delta Region,China[J].Aerosol & Air Quality Research,17
中华人民共和国生态环境部.2017.中国环境年报2017[R].北京:中华人民共和国生态环境部