摘要
基于Sunset碳分析仪对上海城区冬季重污染期PM_(2. 5)中的有机碳(OC)和元素碳(EC)浓度展开为期一个月(2014年12月1日～31日)的小时分辨率在线连续监测,并采用优化的最小R2算法对二次有机气溶胶(SOC)含量进行了估算。观测期间的PM_(2. 5)、OC和EC的平均浓度(mean±1σ)分别为(67. 5±40. 5)μg·m^(-3),(9. 9±4. 8)μg·m^(-3),(3. 1±1. 7)μg·m^(-3),其中总碳TC占PM_(2. 5)质量浓度比重为32. 2%。OC/EC的平均值为3. 5,SOC的浓度(2. 4±2. 3)μg·m^(-3),占OC比重为24. 5%。EC浓度的日变化与车流量一致,呈现出显著的早晚高值,表明机动车是上海EC的主要污染源。SOC浓度在午后达到极大值,说明光化学反应是SOC形成的重要过程。对采样期间的一次典型污染事件(15日20:00～16日5:00)进行来源分析发现,来自于生物质燃烧输送和机动车一次排放的贡献较少;而SOC占OC的比重明显高于非污染期间,表明二次成核是雾霾期有机气溶胶污染的关键过程。
Based on the sunset carbon analyzer, the hourly resolution of organic carbon (OC) and elemental carbon (EC) concentrations in PM 2.5 during heavy winter pollution in Shanghai City was carried out for one month (December 1 to 31, 2014). On-line continuous monitoring and estimation of secondary organic aerosol (SOC) content using the optimized minimum R2 algorithm. The average concentration of PM 2.5 , OC and EC during observation (mean±1σ) was (67.5±40.5)μg ·m^-3 ,(9.9±4.8)μg ·m ^-3 ,(3.1±1.7)μg ·m ^-3 , where in the total carbon TC accounts for 32.2% of the mass concentration of PM 2.5 . The average value of OC/EC is 3.5, and the concentration of SOC is (2.4±2.3)μg ·m ^-3 , accounting for 24.5% of OC. The daily variation of EC concentration is consistent with OC, showing a significant morning and evening high value, indicating that the motor vehicle is the main source of pollution for Shanghai EC. The SOC concentration reaches a maximum value in the afternoon, indicating photochemical reaction is an important process of SOC formation. Source analysis of a typical pollution event during sampling (from 20:00 to 5:00 on the 15th) found that there is less contribution from biomass combustion and primary emissions from motor vehicles. The proportion of SOC to OC is significantly higher than that of non-polluting period, indicating that secondary nucleation is the key processes in the organic aerosol pollution during the haze period.
作者
刘子贺
常运华
鲍孟盈
章炎麟
曹芳
陈耿
邵生成
范美益
刘寿东
LIU Zi-he;CHANG Yun-hua;BAO Meng-ying;ZHANG Yan-lin;CAO Fang;CHEN Geng;SHAO Sheng-cheng;FAN Mei-yi;LIU Shou-dong(Yale~NUIST Center on Atmospheric Environment,School of Atmoshperic Physics, Nanjing 210044, China;Yale~NUIST Center on Atmospheric Environment,Nanjing University of Information Science and Technology, Nanjing 210044, China)
出处
《科学技术与工程》
北大核心
2019年第11期328-338,共11页
Science Technology and Engineering
基金
国家重点研发计划(2017YFC0210101)
国家自然科学基金(41705100
91644103
41603104)
江苏省自然科学基金(BK20170946)
江苏省高校面上项目(17KJB170011)资助
