华南水稻秸秆焚烧期碳质气溶胶组分特征及源贡献评估  

Characteristics and Sources of Carbonaceous Aerosols during the Crop Straw Burning Seasons in Southern China

作　　者：蒋斌 陈多宏[2] 张涛 袁鸾 周炎 沈劲 张春林 王伯光 JIANG Bin;CHEN Duohong;ZHANG Tao;YUAN Luan;ZHOU Yan;SHEN Jing;ZHANG Chunlin;WANG Boguang(Institute for Environmental and Climate Research,Jinan University,Guangzhou 511443,P.R.China;Guangdong Ecological and Environmental Monitoring Center/State Environmental Protection Key Laboratory of Regional Air Quality Monitoring,Guangzhou 510308,P.R.China;JNU-QUT Joint Laboratory for Air Quality Science and Management,Jinan University,Guangzhou 511443,P.R.China)

机构地区：[1]暨南大学环境与气候研究院,广东广州511443 [2]广东省生态环境监测中心/国家环境保护区域空气质量监测重点实验室,广东广州510308 [3]暨南大学-昆士兰科技大学空气质量科学与管理联合实验室,广东广州511443

出　　处：《生态环境学报》2022年第12期2358-2366,共9页Ecology and Environmental Sciences

基　　金：国家重点研发计划(2018YFE0106900);中央高校基本科研业务费专项资金(11621049)。

摘　　要：近年来中国空气质量得到了明显改善,但PM_(2.5)污染事件依旧频发,农作物秸秆焚烧是重要的诱发因素之一。为探讨华南地区水稻秸秆集中焚烧情形下的碳质气溶胶组分特征,于2014年夏秋水稻收割期在“中国广东大气超级站”开展了两期在线观测。结果显示,夏收期元素碳(EC)和有机碳(OC)的平均质量浓度分别为(2.5±1.3)μg·m^(-3)和(6.6±2.5)μg·m^(-3);秋收期则是夏收期的两倍,分别为(5.8±3.9)μg·m^(-3)和(13.6±8.5)μg·m^(-3)。总碳(TC)平均占ρ(PM_(2.5))的30.9%±3.7%和26.8%±7.1%,是PM_(2.5)的重要组成部分。夏收期ρ(EC)/ρ(PM_(2.5))和ρ(OC)/ρ(PM_(2.5))均随ρ(PM_(2.5))的增加而下降,占比之和从74.0%下降至18.3%,而ρ(OC)/ρ(EC)比值则随ρ(PM_(2.5))的增加从1.7逐渐增长至4.4。而秋收期在相对稳定的源排放和静稳的气象条件加持下,ρ(EC)/ρ(PM_(2.5))、ρ(OC)/ρ(PM_(2.5))和ρ(OC)/ρ(EC)比值随ρ(PM_(2.5))的变化均维持相对稳定,ρ(EC)和ρ(OC)显著相关(r=0.91),且ρ(OC)无明显日变化特征。基于EC示踪法和K+质量平衡估算,夏收期OC受光化学反应影响显著,二次有机碳(SOC)的平均质量浓度为(3.7±2.4)μg·m^(-3),占ρ(OC)的52.1%±22.2%;生物质燃烧排放的有机碳(OC_(bb))为(0.8±0.4)μg·m^(-3),占ρ(OC)的12.4%±5.9%。受强生物质燃烧排放的影响,秋收期ρ(OC_(bb))平均为(8.5±5.0)μg·m^(-3),对OC的贡献高达66.6%±18.7%;而ρ(SOC)仅为(1.9±2.5)μg·m^(-3),ρ(SOC)/ρ(OC)比值降至14.5%±16.5%。与OC不同的是,化石燃料燃烧排放始终是华南地区EC的最大贡献源。秋收期生物质燃烧排放可显著提升PM_(2.5)质量浓度,在不利气象条件下易引发污染事件,因此需重点加强对华南秋收期农作物秸秆集中焚烧的管控。In recent years,air quality has been significantly improved in China,but PM_(2.5)pollution events are still occurring frequently,with centralized burning of crop straw being one of the most important factors.To investigate the characteristics of carbon components under the centralized burning of crop straw in South China,two online observations were carried out at“The China Guangdong Atmospheric Super Monitoring Station”in Guangdong,China,during summer and autumn harvest seasons in 2014.The results showed that the mean mass concentrations of elemental carbon(EC)and organic carbon(OC)during summer harvest season were(2.5±1.3)μg·m^(-3)and(6.6±2.5)μg·m^(-3),while those during the autumn harvest season were(5.8±3.9)μg·m^(-3)and(13.6±8.5)μg·m^(-3),respectively,about twice as high as those during the summer harvest season.The total carbon(TC),as an important component ofρ(PM_(2.5)),accounted for 30.9%±3.7%and 26.8%±7.1%ofρ(PM_(2.5))on average.Bothρ(EC)/ρ(PM_(2.5))andρ(OC)/ρ(PM_(2.5))decreased with increasing concentrations ofρ(PM_(2.5))during summer harvest season,with the sum of the ratios decreasing from 74.0%to 18.3%,while theρ(OC)/ρ(EC)ratio gradually increased from 1.7 to 4.4.In contrast,the ratios ofρ(EC)/ρ(PM_(2.5)),ρ(OC)/ρ(PM_(2.5))andρ(OC)/ρ(EC)remained relatively stable withρ(PM_(2.5))concentrations during the autumn harvest season under the relatively stable source emission and stationary meteorological conditions.ρ(EC)andρ(OC)were significantly correlated(r=0.91),andρ(OC)had no obvious diurnal variation.Based on the EC tracer method and potassium mass balance estimation,OC was significantly affected by photochemical reactions during the summer harvest season,and the mean mass concentration of secondary organic carbon(SOC)was(3.7±2.4)μg·m^(-3),accounting for 52.1%±22.2%ofρ(OC).OC from biomass burning(OC_(bb))was(0.8±0.4)μg·m^(-3),accounting for 12.4%±5.9%ofρ(OC).Additionally,due to the impact of strong biomass combustion emissions,theρ(OC_(bb))was(8.5±5.0)μg�

关 键 词：华南 PM_(2.5) 碳质组分 二次有机碳 生物质燃烧 

分 类 号：X16[环境科学与工程—环境科学]