Analysis of Air Pollution Characteristics and Associated Compound Air Pollution Case in Nanjing from 2015 to 2021
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摘要: 探究细颗粒物(PM2.5)和臭氧(O3)污染的时间变化特征,阐明PM2.5和O3复合污染过程中不同阶段环境空气污染物及气溶胶粒径分布的详细演变过程,对南京及长三角地区的大气污染防治具有重要指导意义. 本文使用2015—2021年南京市环境空气污染物小时浓度数据,分析了该地区多年大气污染演变过程,并选取2015年10月12—17日时间段作为复合污染典型个例,对其生消过程和内在机理进行了详细分析. 结果表明:①2015—2021年南京市各种大气污染物的变化特征具有明显差异. PM2.5、PM10和SO2浓度的年下降率分别为8.9%、6.2%和15.4%,O3浓度变化较小. CO浓度在2016年达峰后以每年7.6%的速率下降. NO2浓度在2015—2019年呈增加趋势. ②2015—2021年污染特征发生较大变化,由PM2.5为主导变为由O3为主导的大气复合污染. PM2.5污染频次和强度均显著降低,O3污染频次和强度均未发生显著变化. ③污染过程中不同阶段的气溶胶数浓度谱均呈双峰型,但峰值粒径和浓度有较大差异. PM2.5污染阶段,颗粒物峰值粒径位于30 nm和100 nm处,且峰值粒径数浓度最低. 数浓度谱中爱根核模态的峰值粒径在NO2污染阶段向小粒径段偏移,位于22~26 nm之间,而在PM2.5和O3复合污染阶段,其峰值粒径则向大粒径段偏移,位于30 nm处;积聚模态的峰值粒径没有变化,但峰值数浓度和峰宽均增大,尤其是>100 nm粒径的数浓度明显高于污染前. O3污染阶段,数浓度谱峰值粒径没有变化,但峰值浓度显著增加,尤其是爱根核模态的峰值浓度是污染前的3~5倍. 在污染过程的不同阶段内,环境空气污染物和各模态气溶胶数浓度呈现不同的日变化特征. 研究显示,长三角地区城市O3污染和PM2.5污染存在密切的内在联系,复合污染防控和治理需要重点关注本地污染物变化特征和排放源影响,尤其是影响O3生成的前驱污染物质.Abstract: The Yangtze River Delta (YRD) urban agglomeration is the most economically developed and urbanized area in China, and it is an important intersection between the ‘Belt and Road Initiative’ and the Yangtze River Economic Belt. Nanjing is a megacity in the YRD region and an important central city in the eastern region. The rapid development of urbanization has an obvious regional radiation effect. The industry, traffic and population of Nanjing and surrounding areas have shown rapid growing pollution problems. Studies on the spatial-temporal characteristics of air pollution have been extensively carried out, but research remains scarce in long-term systematic tracking investigation on the relationship between air pollutants and meteorological variables, especially in China′s urban sites (e.g. Nanjing) and recent comprehensive environmental pollution control. Here, we used hourly concentrations of six air pollutants and meteorological data in Nanjing between 2015 and 2021 and revealed the characteristics of PM2.5 and ozone (O3) pollution and their interactions with meteorological conditions. In addition, the pollution types of megacities were mostly compound air pollution. Based on aerosol size distribution data (10 nm-10 μm), we selected a typical compound air pollution episode (October 12th to 17th, 2015) in Nanjing to further clarify the local pollution characteristics. The results showed that the characteristics of six ambient air pollutants differed from one another. The concentrations of PM2.5, PM10, and SO2 decreased significantly, with an average annual decline rate of 8.9%, 6.2% and 15.4%, respectively. In contrast, NO2 showed an upward trend from 2015 to 2019. CO peaked in 2016 and then declined at a rate of 7.6% per year. The concentration of O3 showed a small variation during 2015-2021. Overall, the type of air pollution in Nanjing underwent complex changes, shifting from PM2.5 dominance to O3 dominance. The frequency and intensity of PM2.5 dominated pollution decreased notably, while the frequency and intensity of O3 dominated pollution did not change significantly. At different air pollution evolution stages, the number concentration spectra of aerosols were bimodal while the peak particle size and concentration were different. The peak aerosol concentrations were the lowest in the PM2.5 pollution stage, with peak values of 30 nm and 100 nm, respectively. The aerosol size distribution peaks in nucleation mode shifted to smaller size pattern in the NO2 pollution stage, and the value was 22-26 nm. In PM2.5 and O3 combined pollution stage, the first peak of aerosol distribution in nucleation mode shifted to a larger size pattern around 30 nm, which differed from that in accumulation mode, and the second peak concentration increased and peak width became wider, especially for the size > 100 nm. In the O3 dominated pollution stage, the peak aerosol size remained unchanged, but the peak concentration increased significantly, especially the nucleation mode aerosol, which was 3-5 times higher than the counterpart before the pollution. In all different pollution stages, ambient air pollutants and aerosol number concentrations in different modes showed obvious diurnal variations. The coordinated prevention and control of PM2.5 and O3 pollution in Nanjing City needs to focus on the characteristics of local pollutants and the impact of emission sources, especially the variation and emission sources of precursors affecting O3 pollution.
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Key words:
- PM2.5 /
- O3 /
- air combined pollution /
- number concentration /
- size distribution
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表 1 污染不同阶段环境空气污染物、气象要素和数浓度汇总
Table 1. The summary of ambient air pollutants, meteorological variables, and number concentration in different stage of the combined pollution
项目 污染前 NO2污染阶段 PM2.5污染阶段 PM2.5和O3复合污染阶段 O3污染阶段 污染后 PM2.5浓度/(μg/m3) 39.7±10.4 54.8±12.6 78.0±13.2 117.6±43.3 74.7±43.9 48.3±12.3 PM10浓度/(μg/m3) 97.7±16.2 126.5±28.0 165.6±28.9 204.0±60.4 129.8±62.1 92.3±19.0 NO2浓度/(μg/m3) 61.4±26.1 85.1±39.0 113.0±33.2 99.1±30.9 66.7±30.8 61.8±27.9 SO2浓度/(μg/m3) 23.0±6.7 22.5±8.0 42.4±25.4 36.2±13.8 21.3±7.6 21.2±5.7 CO浓度/(mg/m3) 0.8±0.3 1.1±0.3 1.7±0.5 1.5±0.3 1.0±0.3 0.9±0.2 O3浓度/(μg/m3) 61.5±43.6 61.4±58.8 62.0±55.7 89.2±74.5 87.5±65.1 74.8±52.4 核模态数浓度/cm−3 2 885±3 444 2 229±2 488 911±536 2 760±2 594 10 513±6 948 5 996±4 094 爱根核模态数浓度/cm−3 9 940±3 580 6 483±2 065 5 531±2 083 10 711±7 268 31 402±18 165 18 891±9 060 积聚核模态数浓度/cm−3 3 409±1 245 2759±478 2 507±460 5 199±1 919 6 565±1 490 5 409±2 052 粗模态数浓度/cm−3 1±1 2±1 2±1 4±1 3±1 2±1 总数浓度/cm−3 16 235±6 285 11 472±4 261 8 951±2 718 18 674±10 165 48 483±24 355 30 298±12 525 气温/℃ 15.5±4.4 15.9±4.9 16.7±5.0 19.2±4.5 20.4±3.5 19.8±2.9 RH/% 60.2±21.0 55.7±24.5 60.2±22.5 64.7±21.7 67.9±20.9 66.1±19.1 风速/(m/s) 1.4±1.1 1.1±0.5 0.8±0.4 1.3±0.6 1.6±0.6 1.8±0.6 能见度/km 6.6±2.4 5.6±3.1 3.8±1.9 2.1±1.6 2.3±2.2 4.0±3.2 -
[1] WANG P F,GUO H,HU J L,et al.Responses of PM2.5 and O3 concentrations to changes of meteorology and emissions in China[J].Science of the Total Environment,2019,662:297-306. doi: 10.1016/j.scitotenv.2019.01.227 [2] ZHENG B,TONG D,LI M,et al.Trends in China's anthropogenic emissions since 2010 as the consequence of clean air actions[J].Atmospheric Chemistry and Physics,2018,18(19):14095-14111. doi: 10.5194/acp-18-14095-2018 [3] LI K,JACOB D J,LIAO H,et al.Anthropogenic drivers of 2013-2017 trends in summer surface ozone in China[J].Proceedings of the National Academy of Sciences of the United States of America,2019,116(2):422-427. doi: 10.1073/pnas.1812168116 [4] WANG Y S,YAO L,WANG L L,et al.Mechanism for the formation of the January 2013 heavy haze pollution episode over central and Eastern China[J].Science China Earth Sciences,2014,57(1):14-25. doi: 10.1007/s11430-013-4773-4 [5] 姜华,高健,李红,等.我国大气污染协同防控理论框架初探[J].环境科学研究,2022,35(3):601-610.JIANG H,GAO J,LI H,et al.Preliminary research on theoretical framework of cooperative control of air pollution in China[J].Research of Environmental Sciences,2022,35(3):601-610. [6] 李欢欢,张凯,牛璨,等.保定市PM2.5和臭氧污染特征分析[J].环境科学研究,2022,35(3):683-690.LI H H,ZHANG K,NIU C,et al.PM2.5 and O3 pollution characteristics in Baoding City[J].Research of Environmental Sciences,2022,35(3):683-690. [7] 唐颖潇,姚青,蔡子颖,等.基于过程分析的京津冀区域典型城市臭氧成因[J].环境科学,2022,43(6):2917-2927.TANG Y X,YAO Q,CAI Z Y,et al.Exploring formation of ozone in typical cities in Beijing-Tianjin-Hebei region using process analysis[J].Environmental Science,2022,43(6):2917-2927. [8] 赵伟,吕梦瑶,卢清,等.热带气旋对珠三角秋季臭氧污染的影响[J].环境科学,2022,43(6):2957-2965.ZHAO W,LÜ M Y,LU Q,et al.Effects of tropical cyclones on ozone pollution in the Pearl River Delta in autumn[J].Environmental Science,2022,43(6):2957-2965. [9] LIU Z R,WANG Y S,HU B,et al.Elucidating the quantitative characterization of atmospheric oxidation capacity in Beijing,China[J].Science of the Total Environment,2021,771:145306. doi: 10.1016/j.scitotenv.2021.145306 [10] 吴安南,黄小娟,何仁江,等.“大气十条”实施结束川南城市群秋季霾污染过程中水溶性离子特征[J].环境科学,2022,43(3):1170-1179. doi: 10.13227/j.hjkx.202106019WU A N,HUANG X J,HE R J,et al.Characteristics of water-soluble ions in an autumn haze process in the southern Sichuan urban agglomeration after the implementation of China's Air Pollution Prevention and Control Action Plan[J].Environmental Science,2022,43(3):1170-1179. doi: 10.13227/j.hjkx.202106019 [11] WANG L L,LIU Z R,SUN Y,et al.Long-range transport and regional sources of PM2.5 in Beijing based on long-term observations from 2005 to 2010[J].Atmospheric Research,2015,157:37-48. doi: 10.1016/j.atmosres.2014.12.003 [12] 张涵,姜华,高健,等.PM2.5与臭氧污染形成机制及协同防控思路[J].环境科学研究,2022,35(3):611-620.ZHANG H,JIANG H,GAO J,et al.Formation mechanism and management strategy of cooperative control of PM2.5 and O3[J].Research of Environmental Sciences,2022,35(3):611-620. [13] 江家坤,马莹,黄学良,等.云浮市2018—2020年颗粒物和臭氧污染特征及污染案例研究[J].环境科学研究,2022,35(3):691-698.JIANG J K,MA Y,HUANG X L,et al.Pollution characteristics and a pollution case of particulate matter and O3 in Yunfu City from 2018 to 2020[J].Research of Environmental Sciences,2022,35(3):691-698. [14] 李红,彭良,毕方,等.我国PM2.5与臭氧污染协同控制策略研究[J].环境科学研究,2019,32(10):1763-1778.LI H,PENG L,BI F,et al.Strategy of coordinated control of PM2.5 and ozone in China[J].Research of Environmental Sciences,2019,32(10):1763-1778. [15] 花丛,江琪,迟茜元,等.我国中东部地区2015—2020年夏半年PM2.5和臭氧复合污染气象特征分析[J].环境科学研究,2022,35(3):650-658.HUA C,JIANG Q,CHI X Y,et al.Meteorological characteristics of PM2.5-O3 air combined pollution in central and eastern China in the summer half years of 2015-2020[J].Research of Environmental Sciences,2022,35(3):650-658. [16] MENG Z,DABDUB D,SEINFELD J H.Chemical coupling between atmospheric ozone and particulate matter[J].Science,1997,277(5322):116-119. doi: 10.1126/science.277.5322.116 [17] 王雨燕,杨文,王秀艳,等.淄博市城郊臭氧污染特征及影响因素分析[J].环境科学,2022,43(1):170-179. doi: 10.13227/j.hjkx.202105009WANG Y Y,YANG W,WANG X Y,et al.Characteristics of ozone pollution and influencing factors in urban and suburban areas in Zibo[J].Environmental Science,2022,43(1):170-179. doi: 10.13227/j.hjkx.202105009 [18] LYU X P,CHEN N,GUO H,et al.Ambient volatile organic compounds and their effect on ozone production in Wuhan,central China[J].Science of the Total Environment,2016,541:200-209. doi: 10.1016/j.scitotenv.2015.09.093 [19] 陈楠,陈立,王莉莉,等.2015—2020年湖北省PM2.5和臭氧复合污染特征演变分析[J].环境科学研究,2022,35(3):659-672.CHEN N,CHEN L,WANG L L,et al.Characteristic and trend analysis of PM2.5 and ozone in air compound pollution in Hubei Province during 2015-2020[J].Research of Environmental Sciences,2022,35(3):659-672. [20] ZHAO D D,LIU G J,XIN J Y,et al.The haze pollution under strong atmospheric oxidization capacity in summer in Beijing:insights into the formation mechanism of atmospheric physicochemical process[J].Atmospheric Chemistry and Physics,2020,20(8):4575-4592. doi: 10.5194/acp-20-4575-2020 [21] GAO J H,LI Y,ZHU B,et al.What have we missed when studying the impact of aerosols on surface ozone via changing photolysis rates?[J].Atmospheric Chemistry and Physics,2020,20(18):10831-10844. doi: 10.5194/acp-20-10831-2020 [22] CHEN L,ZHU J,LIAO H,et al.Meteorological influences on PM2.5 and O3 trends and associated health burden since China's clean air actions[J].Science of the Total Environment,2020,744:140837. doi: 10.1016/j.scitotenv.2020.140837 [23] 何超,慕航,杨璐,等.中国暖季近地面臭氧浓度空间格局演变及主要气象驱动因素[J].环境科学,2021,42(9):4168-4179. doi: 10.13227/j.hjkx.202009228HE C,MU H,YANG L,et al.Spatial variation of surface ozone concentration during the warm season and its meteorological driving factors in China[J].Environmental Science,2021,42(9):4168-4179. doi: 10.13227/j.hjkx.202009228 [24] 赵辉,郑有飞,吴晓云,等.江苏省大气复合污染特征与相关气象驱动[J].中国环境科学,2018,38(8):2830-2839. doi: 10.19674/j.cnki.issn1000-6923.2018.0297ZHAO H,ZHENG Y F,WU X Y,et al.Atmospheric compound pollution characteristics and the effects of meteorological factors in Jiangsu Province[J].China Environmental Science,2018,38(8):2830-2839. doi: 10.19674/j.cnki.issn1000-6923.2018.0297 [25] 王红磊,沈利娟,唐倩,等.嘉兴市不同天气条件下大气污染物和气溶胶化学组分的分布特征[J].环境科学,2017,38(9):3594-3604. doi: 10.13227/j.hjkx.201702093WANG H L,SHEN L J,TANG Q,et al.Distribution characteristics of air pollutants and aerosol chemical components under different weather conditions in Jiaxing[J].Environmental Science,2017,38(9):3594-3604. doi: 10.13227/j.hjkx.201702093 [26] 付志民,孙在,贾峥,等.杭州市超细微粒数浓度和粒径分布特征[J].环境科学研究,2012,25(3):259-264. doi: 10.13198/j.res.2012.03.18.fuzhm.007FU Z M,SUN Z,JIA Z,et al.Number concentration spectrum and size distribution of atmospheric ultrafine particles in Hangzhou City[J].Research of Environmental Sciences,2012,25(3):259-264. doi: 10.13198/j.res.2012.03.18.fuzhm.007 [27] STANIER C O,KHLYSTOV A Y,PANDIS S N.Ambient aerosol size distributions and number concentrations measured during the Pittsburgh Air Quality Study (PAQS)[J].Atmospheric Environment,2004,38(20):3275-3284. doi: 10.1016/j.atmosenv.2004.03.020 [28] 尚倩,李子华,杨军,等.南京冬季大气气溶胶粒子谱分布及其对能见度的影响[J].环境科学,2011,32(9):2750-2760. doi: 10.13227/j.hjkx.2011.09.028SHANG Q,LI Z H,YANG J,et al.Size distributions of aerosol particles and the impact on visibility in winter of Nanjing[J].Environmental Science,2011,32(9):2750-2760. doi: 10.13227/j.hjkx.2011.09.028 [29] KANG H Q,et al.Analysis of a long-lasting haze episode in Nanjing,China[J].Atmospheric Research,2013,120/121:78-87. doi: 10.1016/j.atmosres.2012.08.004 [30] 于兴娜,马佳,朱彬,等.南京北郊秋冬季相对湿度及气溶胶理化特性对大气能见度的影响[J].环境科学,2015,36(6):1919-1925.YU X N,MA J,ZHU B,et al.Effects of relative humidity and aerosol physicochemical properties on atmospheric visibility in northern suburb of Nanjing[J].Environmental Science,2015,36(6):1919-1925. [31] 张璐瑶,牛生杰,王天舒,等.南京冬季晴天及雾-霾天气纳米气溶胶粒子谱日变化比较[J].中国环境科学,2019,39(7):2699-2709.ZHANG L Y,NIU S J,WANG T S,et al.The comparison of diurnal variation of nanoparticle spectra in sunny and fog-haze days during winter in Nanjing[J].China Environmental Science,2019,39(7):2699-2709. [32] 毛卓成,许建明,杨丹丹,等.上海地区PM2.5-O3复合污染特征及气象成因分析[J].中国环境科学,2019,39(7):2730-2738.MAO Z C,XU J M,YANG D D,et al.Analysis of characteristics and meteorological causes of PM2.5-O3 compound pollution in Shanghai[J].China Environmental Science,2019,39(7):2730-2738. [33] 王倩.2019年5月上海复合污染过程中挥发性有机物的污染特征及来源[J].环境科学,2020,41(6):2555-2564.WANG Q.Chemical characteristics and sources of volatile organic compounds in Shanghai during an ozone and particulate pollution episode in may 2019[J].Environmental Science,2020,41(6):2555-2564. [34] HUANG X,WANG Z L,DING A J.Impact of aerosol-PBL interaction on haze pollution:multiyear observational evidences in North China[J].Geophysical Research Letters,2018,45(16):8596-8603. doi: 10.1029/2018GL079239 [35] 郝建奇,葛宝珠,王自发,等.2014年6月南京大气复合污染观测[J].环境科学,2017,38(9):3585-3593.HAO J Q,GE B Z,WANG Z F,et al.Observational study of air pollution complex in Nanjing in June 2014[J].Environmental Science,2017,38(9):3585-3593. [36] HUANG X,DING A J,WANG Z L,et al.Amplified transboundary transport of haze by aerosol–boundary layer interaction in China[J].Nature Geoscience,2020,13(6):428-434. doi: 10.1038/s41561-020-0583-4 [37] SHU L,WANG T J,HAN H,et al.Summertime ozone pollution in the Yangtze River Delta of eastern China during 2013-2017:Synoptic impacts and source apportionment[J].Environmental Pollution,2020,257:113631. doi: 10.1016/j.envpol.2019.113631 [38] WANG H L,AN J L,SHEN L J,et al.Mechanism for the formation and microphysical characteristics of submicron aerosol during heavy haze pollution episode in the Yangtze River Delta,China[J].Science of the Total Environment,2014,490:501-508. doi: 10.1016/j.scitotenv.2014.05.009 [39] LI L,LI Q,HUANG L,et al.Air quality changes during the COVID-19 lockdown over the Yangtze River Delta Region:an insight into the impact of human activity pattern changes on air pollution variation[J].Science of the Total Environment,2020,732:139282. doi: 10.1016/j.scitotenv.2020.139282 [40] SHEN L J,WANG H L,ZHU B,et al.Impact of urbanization on air quality in the Yangtze River Delta during the COVID-19 lockdown in China[J].Journal of Cleaner Production,2021,296:126561. doi: 10.1016/j.jclepro.2021.126561 [41] WANG H L,MIAO Q,SHEN L J,et al.Characterization of the aerosol chemical composition during the COVID-19 lockdown period in Suzhou in the Yangtze River Delta,China[J].Journal of Environmental Sciences,2021,102:110-122. doi: 10.1016/j.jes.2020.09.019 [42] WANG Z B,WU Z J,YUE D L,et al.New particle formation in China:current knowledge and further directions[J].Science of the Total Environment,2017,577:258-266. doi: 10.1016/j.scitotenv.2016.10.177 [43] WANG H L,ZHU B,SHEN L J,et al.Number size distribution of aerosols at Mt.Huang and Nanjing in the Yangtze River Delta,China:effects of air masses and characteristics of new particle formation[J].Atmospheric Research,2014,150:42-56. doi: 10.1016/j.atmosres.2014.07.020 [44] HARRIS S J,MARICQ M M.Signature size distributions for diesel and gasoline engine exhaust particulate matter[J].Journal of Aerosol Science,2001,32(6):749-764. doi: 10.1016/S0021-8502(00)00111-7 [45] KULMALA M,VEHKAMÄKI H,PETÄJÄ T,et al.Formation and growth rates of ultrafine atmospheric particles:a review of observations[J].Journal of Aerosol Science,2004,35(2):143-176. doi: 10.1016/j.jaerosci.2003.10.003 [46] 章澄昌,周文贤.大气气溶胶教程[M].北京:气象出版社,1995. -