摘要
于2021年1~2月在重庆典型城区万州区(WZ)、渝北区(YB)和双桥区(SQ)同步采集PM_(2.5)样品,分析冬季碳质气溶胶的污染特征、来源及潜在源区.结果表明,观测期间SQ的ρ(PM_(2.5))、ρ(OC)和ρ(EC)均值分别为(72.6±33.3)、(18.2±8.2)和(4.4±1.7)μg·m^(-3),高于WZ[(67.2±30.3)、(17.2±7.4)和(5.1±2.4)μg·m^(-3)]和YB[(63.4±25.7)、(15.4±6.3)和(4.2±1.9)μg·m^(-3)].与清洁日相比,WZ污染日EC浓度及其对总碳的贡献率均涨幅最大(103.0%和8.1%),但OC/EC值下降最明显(-10.5%),表明WZ污染日碳质气溶胶的一次排放明显增强.观测期间SQ和YB的ρ(SOC)均值分别为(7.7±4.8)μg·m^(-3)和(6.9±2.8)μg·m^(-3),明显高于WZ[(4.5±1.9)μg·m^(-3)],表明二次转化对SQ和YB碳质气溶胶的影响相对较大.此外,与WZ不同,SQ和YB的SOC/OC值整体随PM_(2.5)浓度上升而增大,且SOC浓度与气溶胶液态水含量(AWC)、NO_(2)浓度和NOR值等均显著线性相关(P<0.01),表明通过液相反应生成含—NO_(2)官能团的SOC可能是SQ和YB碳质气溶胶浓度持续上升的主要因素.正定矩阵因子(PMF)解析结果表明,WZ的生物质/煤炭燃烧混合源贡献率(47.4%)明显高于YB(34.2%)和SQ(38.1%),而YB受汽油车排放和二次转化的影响较为突出.浓度权重轨迹分析(CWT)结果表明,各城区污染日碳质气溶胶主要受本地及其东北方向相邻城区(如长寿区)的影响.
To investigate the characteristics,source apportionment,and potential source areas of carbonaceous aerosols in Chongqing during winter,PM_(2.5) samples were collected from January 2021 to February 2021 in the urban areas of Wanzhou(WZ),Yubei(YB),and Shuangqiao(SQ).The results showed that the average mass concentrations of PM_(2.5),OC,and EC in SQ were(72.6±33.3),(18.2±8.2),and(4.4±1.7)μg·m^(-3),respectively,higher than those in WZ[(67.2±30.3),(17.2±7.4),and(5.1±2.4)μg·m^(-3)]and YB[(63.4±25.7),(15.4±6.3),and(4.2±1.9)μg·m^(-3)].Compared with that during the clear period,the concentration and fraction of EC in total carbon increased by 103.0% and 8.1%,respectively,in WZ compared to that in other areas during pollution period,whereas the OC/EC ratio was decreased significantly(-10.5%),indicating that the primary emission of carbonaceous aerosols increased significantly during the pollution period.The average mass concentrations of secondary organic carbon(SOC)in SQ and YB were(7.7±4.8)μg·m^(-3) and(6.9±2.8)μg·m^(-3) significantly higher,respectively,than that in WZ[(4.5±1.9)μg·m^(-3)]during the campaign.This indicated that the secondary transformation had a greater influence on the carbonaceous aerosols in SQ and YB than that in WZ.Furthermore,in contrast to that in WZ,the ratios of SOC/OC were increased with the increase in PM_(2.5) concentrations,and significant correlations between SOC concentration and aerosol water content,NO_(2) concentration,and the value of NOR were observed in SQ and YB(P<0.01),indicating that the increasing of carbonaceous aerosol concentrations might be mainly driven by the SOC with—NO_(2) groups produced by aqueous chemical reactions during winter in SQ and YB.The positive definite matrix factor(PMF)results in these urban areas showed that the contribution of biomass/coal combustion source in WZ(47.4%)was significantly higher than that in YB(34.2%)and SQ(38.1%),whereas the gasoline motor vehicle emission and secondary transformation impacts were more significant in YB.The results of the concentration weighted trajectory(CWT)showed that the potential sources of carbonaceous aerosols were mainly the local and northeastern parts of these urban areas(such as Changshou).
作者
彭超
李振亮
向英
王晓宸
汪凌韬
张晟
翟崇治
陈阳
杨复沫
翟天宇
PENG Chao;LI Zhen-liang;XIANG Ying;WANG Xiao-chen;WANG Ling-tao;ZHANG Sheng;ZHAI Chong-zhi;CHENYang;YANG Fu-mo;ZHAI Tian-yu(Chongqing Academy of Eco-Environmental Science,Chongqing 401147,China;Chongqing Branch Academy of Chinese Research Academy of Environmental Sciences,Chongqing 401147,China;Key Laboratory for Urban Atmospheric Environment Integrated Observation&Pollution Prevention and Control of Chongqing,Chongqing 401147,China;Chongqing Institute of Green and Intelligent Technology,Chinese Academy of Sciences,Chongqing 400714,China;College of Architecture and Environment,Sichuan University,Chengdu 610065,China;College of Environmental Sciences and Engineering,Peking University,Beijing 100871,China)
出处
《环境科学》
EI
CAS
CSCD
北大核心
2024年第1期48-60,共13页
Environmental Science
基金
重庆市自然科学基金项目(CSTB2022NSCQ-MSX0504)
重庆市博士“直通车”科研项目(CSTB2022BSXM-JCX0157)
重庆市基本科研业务费计划项目(Cqhky2021jxjl00004)。
关键词
碳质气溶胶
污染过程
二次有机碳
来源解析
重庆
carbonaceous aerosols
pollution period
secondary organic carbon
source apportionment
Chongqing
