南京亚微米级颗粒物化学组成的季节变化、粒径分布和来源  

Seasonal Variations,Size Distributions,and Sources of Chemical Components of Submicron Particulate Matter in Nanjing

作　　者：徐振麒 尚玥 丁峰 谢鸣捷 王勤耕[4] XU Zhen-qi;SHANG Yue;DING Feng;XIE Ming-jie;WANG Qin-geng(Jiangsu Key Laboratory of Atmospheric Environment Monitoring and Pollution Control,Collaborative Innovation Center of Atmospheric Environment and Equipment Technology,School of Environmental Science&Engineering,Nanjing University of Information Science&Technology,Nanjing 210044,China;Shangqiu Bureau of Meteorology,Shangqiu 476000,China;Nanjing Environmental Monitoring Center of Jiangsu Province,Nanjing 210013,China;School of the Environment,Nanjing University,Nanjing 210023,China)

机构地区：[1]南京信息工程大学环境科学与工程学院,大气环境与装备技术协同创新中心,江苏省大气环境监测与污染控制高技术研究重点实验室,南京210044 [2]商丘市气象局,商丘476000 [3]江苏省南京环境监测中心,南京210013 [4]南京大学环境学院,南京210023

出　　处：《环境科学》2023年第3期1310-1318,共9页Environmental Science

基　　金：国家自然科学基金青年科学基金项目(42177211)。

摘　　要：于2016~2017年不同季节在南京大学仙林校区采集分粒径的颗粒物样品,分析了粒径≤1.1μm颗粒物(PM1.1;<0.4、0.4~0.7和0.7~1.1μm)中水溶性离子、碳质组分和元素的浓度.结果表明,受当地扩散条件以及热不稳定组分在高温下挥发分解的影响,PM1.1、OC、NO_(3)^(-)、SO_(4)^(2-)和NH_(+)^(4)浓度均表现出秋冬高、春夏低的特点.而元素碳在春季因工业和道路扬尘贡献的升高达到最大浓度[(1.87±0.98)μg·m^(-3)].根据丰量组分间的特征比值,南京PM1.1中的阴离子由NO_(3)^(-)、SO_(4)^(2-)和Cl^(-)主导,碳质组分主要来自化石燃料燃烧及老化过程.随着温度的升高,热不稳定组分NH_(+)^(4)、NO_(3)^(-)和有机碳的粒径分布向细粒子方向移动;EC因机动车排放强度和扬尘贡献的升高粒径分布向粗粒子方向移动.由于高湿度(>70%)往往伴随着高温(>20℃)及扩散条件的改善,60%~70%的相对湿度更有利于PM1.1中二次无机离子的形成.基于PM1.1化学组分的源解析结果表明,二次形成过程[(66.6±18.3)%]和扬尘[(16.8±14.8)%]是南京PM1.1的主要贡献源,有必要进一步控制各种前体物和扬尘的排放.Size-segregated particulate matter(PM)samples were collected in different seasons from 2016 to 2017 at the Xianlin Campus of Nanjing University.Mass concentrations of water-soluble inorganic ions,carbonaceous components,and elements were analyzed for PM with an aerodynamic diameter≤1.1μm(PM1.1;<0.4μm,0.4-0.7μm,and 0.7-1.1μm).The results showed that PM1.1,OC,NO_(3)^(-),SO_(4)^(2-),and NH_(+)^(4)exhibited higher ambient levels in fall-winter than those in spring-summer,which was attributed to the changes in local diffusion conditions,evaporation,and decomposition of non-refractory components.Elemental carbon(EC)reached its maximum concentration[(1.87±0.98)μg·m^(-3)]in spring due to the increase in industrial and road dust resuspension.According to the characteristic ratio between bulk components,the anions in PM1.1were dominated by NO_(3)^(-),SO_(4)^(2-),and Cl^(-)in Nanjing,and the carbonaceous components were mainly from fossil fuel combustions and associated aging processes.As the ambient temperature increased,the size distributions of thermo-unstable components including NH_(+)^(4),NO_(3)^(-),and OC shifted towards finer particles,whereas EC became more enriched in coarse particles,possibly due to the increase in emission intensity of motor vehicles and fugitive dust contributions.Since high relative humidity(>70%)is often accompanied by high temperature(>20℃)and improved diffusion conditions,a relative humidity of 60%-70%was more conducive to the formation of secondary inorganic ions in PM1.1.Source apportionment results based on the speciation data of PM1.1showed that secondary formation processes[(66.6±18.3)%]and dust resuspension[(16.8±14.8)%]were the main contributors to PM1.1in Nanjing,and further control of the emissions of gaseous precursors and dust is necessary.

关 键 词：PM1.1 化学组分 季节变化 粒径分布 源解析 

分 类 号：X513[环境科学与工程—环境工程]