| 引用本文: | 李致宇，张新，王启元，André S. H. Prévôt，曹军骥，韩月梅.2021.西安夏季大气亚微米颗粒物化学组成与来源的在线观测研究[J].地球环境学报,12(2):170-182 |
| LI Zhiyu, ZHANG Xin, WANG Qiyuan, André S. H. PRÉVÔT, CAO Junji, HAN Yuemei.2021.Characterization of composition and sources of atmospheric submicron particles in Xi’an, China during summer using an aerosol chemical speciation monitor[J].Journal of Earth Environment,12(2):170-182 |
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| 摘要: |
| 西安作为汾渭平原地区最大的城市，大气颗粒物污染形势严峻。2017年夏季期间，在西安市浐灞生态园区运用气溶胶化学组分监测仪，对大气亚微米颗粒物中的非难挥发性组分(NR-PM1)进行了在线监测。观测期间NR-PM1的平均质量浓度为(30.1±15.4) μg∙m−3。其中有机物含量最高，占NR-PM1总质量浓度的63%，其次为硫酸盐（18%）、铵盐（10%）和硝酸盐（9%）。运用正交矩阵因子分析法共解析出两个主要因子，包括烃类有机组分（HOA）和含氧有机组分（OOA），分别占有机物总质量浓度的43%和55%。HOA主要由机动车排放贡献，而OOA主要由气态污染物的二次反应生成。气象因素对NR-PM1的浓度与化学组分的影响较为显著。高硝酸盐阶段发生在高湿、低温条件，可能是由氮氧化物的液相反应产生的。高硫酸盐阶段发生在低湿、高温条件，主要来自于大气光化学反应的贡献。该研究结果为西安及周边地区的空气污染治理决策提供重要的理论依据。 |
| 关键词: 亚微米颗粒物 化学组成 来源 大气过程 气溶胶化学组分监测仪 |
| DOI：10.7515/JEE202027 |
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| 基金项目:中国科学院项目（292020000018）；陕西省重点研发项目（2018-ZDXM3-01）；中国-瑞士科技合作项目“HAZECHINA”（NSFC No. 21661132005 and SNF No. IZLCZ2_169986） |
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| Characterization of composition and sources of atmospheric submicron particles in Xi’an, China during summer using an aerosol chemical speciation monitor |
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LI Zhiyu, ZHANG Xin, WANG Qiyuan, André S. H. PRÉVÔT, CAO Junji, HAN Yuemei
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1. 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
2. CAS Center for Excellence in Quaternary Science and Global Change, Xi’an 710061, China
3. University of Chinese Academy of Sciences, Beijing 100049, China
4. Laboratory of Atmospheric Chemistry, Paul Scherrer Institute (PSI), 5232 Villigen, Switzerland
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| Abstract: |
| Background, aim, and scope Fenwei Basin situated in the middle of China has raised considerable attention for severe air pollution in the past years. Xi’an is the largest city in Fenwei Basin. This study aims at understanding the chemical properties of atmospheric submicron particles based on real time measurement in summer to develop appropriate air pollution control strategies in Xi’an. Materials and methods An Aerodyne quadrupole aerosol chemical speciation monitor was deployed for characterizing the chemical composition of non-refractory submicron particles (NR-PM1) at a suburban site of Xi’an in early summer 2017. Results The mass concentration of NR-PM1 was on average (30.1±15.4) μg·m−3. Organic matter was the dominant component accounting for on average 63% of NR-PM1 mass, followed by sulfate (18%), ammonium (10%), and nitrate (9%). Two factors were retrieved from positive matrix factorization analysis, including a hydrocarbon-like organic aerosol component (HOA) and an oxidized organic aerosol component (OOA). HOA and OOA constituted of 43% and 55% of submicron organic mass, respectively. Discussion Low mass concentrations of NR-PM1 were observed during the rainfall period. An increase of sulfate was observed with increasing temperature and ozone concentration, suggesting that sulfate was produced substantially by atmospheric photochemical reactions. An increase of nitrate was observed with increasing relative humidity and lower temperature, which was possibly associated to nitrate production from aqueous phase reactions or enhanced partitioning of semivolatile nitrate compounds to particle phase. Conclusions Submicron particles had lower mass concentration during the summertime in Xi’an compared to the heavily polluted wintertime. Meteorological parameters substantially influenced the mass loading and composition of NR-PM1. Organics was the dominant component of submicron particles and mainly contributed by primary traffic emissions and secondary formation. Recommendations and perspectives Results obtained herein should be taken into account to develop further air pollution control strategies in Xi’an and surrounding areas. |
| Key words: submicron particles, composition, source, atmospheric process, ACSM |
