森林地区PM2.5中氨基酸的水平、来源及转化  

The levels,sources and atmospheric photochemical processes of amino acids in PM2.5 in forest areas

作　　者：朱玉雯 朱仁果 方小珍 潘媛媛 温泽群 ZHU Yu-wen;ZHU Ren-guo;FANG Xiao-zheng;PAN Yuan-yuan;WEN Ze-qun(School of Earth Sciences,East China University of Technology,Nanchang 330013,China;Jiangxi Province Key Laboratory of the Causes and Control of Atmospheric Pollution,East China University of Technology,Nanchang 330013,China;Department of Earth Sciences,Faculty of Land Resource Engineering,Kunming University of Science and Technology,Kunming 650021,China)

机构地区：[1]东华理工大学地球科学学院,江西南昌330013 [2]东华理工大学,江西省大气污染成因与控制重点实验室,江西南昌330013 [3]昆明理工大学国土资源学院,地球科学系,云南昆明650021

出　　处：《中国环境科学》2021年第1期81-90,共10页China Environmental Science

基　　金：国家自然科学基金资助项目(41463007)。

摘　　要：在春季采集了南昌森林地区(28.75°N,115.71°E)大气PM2.5样品,测定了其结合氨基酸(CAAs)和游离氨基酸(FAAs)的浓度以及甘氨酸(Gly)的氮同位素.结果表明,大气气溶胶中总CAAs的浓度为272.8~4761.5pmol/m^3,总FAAs浓度为56.4~494.0pmol/m^3.通过分析PM2.5中氨基酸的百分比组成,得出CAAs中Pro、Gly、Glu、Leu和Ala为主要氨基酸,分别占总CAAs的(19.5±12.0)%,(19.4±10.6)%,(15.3±4.9)%,(12.8±5.4)%和(9.1±1.6)%.在FAAs中,Gly为最丰富的氨基酸,占总FAAs的(71.1±9.2)%,其他单个FAAs的百分比却很小(占比范围为0.1%~14.3%).FAAs中的中性氨基酸百分占比明显高于其在CAAs中的百分占比,这可能与远距离传输过程中氨基酸的光化学反应有关.通过氨基酸浓度与O3、NO2和温度的相关性分析,发现森林地区气溶胶中FAAs形成与大气光化学过程和热反应有关.气溶胶中δ^15NC-Gly值(-1.0‰~+17.5‰)和δ^15NF-Gly值(-5.5‰~+13.0‰)均接近于土壤源的δ^15NGly值,说明森林地区PM2.5中氨基酸可能主要来源于土壤源.In this study,PM2.5 samples were collected in a forest area of Nanchang(28.75°N,115.71°E)in spring,The concentrations of combined amino acids(CAAs),free amino acids(FAAs)and the nitrogen isotopes of glycine(Gly)were determined.The result showed that the concentrations of total CAAs and the concentrations of total FAAs were 272.8~4761.5pmol/m^3,and 56.4~494.0pmol/m^3 in the atmospheric aerosols,respectively.The fractional percentage of CAAs,Pro,Gly,Glu,Leu and Ala in the total CAAs were(19.5±12.0)%,(19.4±10.6)%,(15.3±4.9)%,(12.8±5.4)% and(9.1±1.6)%,respectively.Gly was the most abundant amino acid,accounting for(71.1±9.2)% of the total FAAs.However,the fractional percentage of other FAAs was very small(proportion range of 0.1%~14.3%).The proportion of neutral amino acids was much higher in FAAs than that in CAAs,which might be related to the photochemical reaction during long-distance transport.According to the correlations between amino acid and O3,NO2 and temperature,we found that the formation of FAAs was associated with atmospheric photochemical processes and thermal reactions in the forest areas.The δ^15NC-Gly value(-1.0‰~+17.5‰)and δ^15NF-Gly value(-5.5‰~+13.0‰)in aerosol were close to the δ^15NGly value from soil sources,indicating that the main source of amino acids in PM2.5 might be from soil emission in the forest areas.

关 键 词：结合氨基酸 游离氨基酸 PM2.5 O3 δ^15NGly 

分 类 号：X513[环境科学与工程—环境工程]