摘要
为探究汾渭平原城市近5a(2017~2021年)大气污染演变及典型污染过程特征,以宝鸡市为例,综合利用空气质量监测数据(6参数)、气象数据及污染期间颗粒物化学组分数据进行分析.结果显示,宝鸡市2017~2021年空气质量改善较为显著,CO-95per (CO日均值第95%分位数)和SO_(2)浓度分别下降了47%和36%,表明宝鸡市近年来控煤效果明显;PM_(2.5)浓度下降了24%,O_(3)-8h-90per浓度(O_(3)日最大8h平均值第90%分位数)年际差异不大,2021年O_(3)-8h-90per浓度与2017年持平,且为近5a最高值,随着PM_(2.5)污染的逐步改善,O_(3)污染开始凸显.PM_(2.5)与O_(x)浓度的相关性在夏半年明显强于冬半年,归因于夏半年较高的O_(3)浓度增强了大气氧化性,促进了二次颗粒物的生成.结合气象要素对冬半年和夏半年污染天分析发现,冬半年低温、高湿、低风速静稳天气最容易导致PM_(2.5)污染,夏半年O_(3)污染天一般出现在高温、低湿天气.对以PM_(2.5)(污染过程1)和PM10(污染过程2)为首要污染物的2个典型污染过程进行对比分析发现,污染过程1中EC (元素碳)和SNA (SO_(4)^(2-)、NO_(3)^(-)和NH_(4)^(+)三者统称)浓度均明显升高,表明本地一次排放以及二次组分均有大幅增加;污染过程2受外来沙尘传输影响,Al、Si、Ca和Fe等地壳元素浓度迅速升高.从PM_(2.5)各组分贡献来看,两次污染过程中贡献最大的分别为SNA(52%)和粉尘(65%).
The evolution of urban air pollution and typical pollution characteristics during the past five years(2017~2021)in the western Fenwei Plain(Baoji City)were investigated.The air quality has been improved significantly from 2017 to 2021 in Baoji City.The concentrations of PM_(2.5),CO-95 per(the 95th percentile of the daily concentrations of CO)and SO_(2) decreased by 24%,47%and 36%,respectively,which indicated that the control of coal combustion was effective in Baoji City.The inter-annual variations of O_(3)-8h-90 per(the 90th percentile of the daily concentrations of O_(3)-8h)were comparable.The pollution of O_(3) should be given more consideration.The correlations between PM_(2.5) and Ox showed higher significance in summer than that in winter.High O_(3) concentrations can contribute to the enhancement of atmospheric oxidation and thus promote the formation of secondary aerosol in summer.The serious PM_(2.5) pollution were attributed to the low temperature,high humidity and low wind speed in winter,while those for O_(3) pollution were high temperature and low humidity in summer.Two typical pollution events were discussed with PM_(2.5)(pollution 1)and PM10(pollution 2)as primary pollutant,respectively.The concentrations of EC(element carbon)and SNA(SO_(4)^(2-),NO_(3)^(-)and NH_(4)^(+))increased significantly in pollution 1,which was attributed to the enhanced local emissions and secondary components.Due to the transport of dust,the concentrations of Al,Si,Ca,Fe and other crustal elements increased significantly in pollution 2.The largest contributors to PM_(2.5) were SNA(52%)and dust(65%)in the two pollution processes,respectively.
作者
时迎强
屈垚
师菊莲
刘随心
王璐瑶
王楠
周岳
张婷
苏慧
朱崇抒
曹军骥
SHI Ying-qiang;QU Yao;SHI Ju-lian;LIU Sui-xin;WANG Lu-yao;WANG Nan;ZHOU Yue;ZHANG Ting;SU Hui;ZHU Chong-shu;CAO Jun-ji(Key Laboratory of Aerosol Chemistry and Physics,State Key Laboratory of Loess and Quaternary Geology,Institute of Earth Environment,Chinese Academy of Sciences,Xi’an 710061,China;Xi’an Institute for Innovative Earth Environment Research,Xi’an 710061,China;National Observation and Research Station of Regional Ecological Environment Change and Comprehensive Management in the Guanzhong Plain,Shaanxi,Xi’an 710499,China;Institute of Atmospheric Physics,Chinese Academy of Sciences,Beijing 100029,China)
出处
《中国环境科学》
CSCD
北大核心
2023年第S1期1-9,共9页
China Environmental Science
基金
大气重污染成因与治理攻关项目(DQGG-05-36)
