Concentrations and light absorption properties of PM_(2.5) organic and black carbon based on online measurements in Lanzhou, China  

作　　者：Pengfei Chen Shichang Kang Qinyi Gan Ye Yu Xianlei Yuan Yajun Liu Lekhendra Tripathee Xiaoxiang Wang Chaoliu Li 

机构地区：[1]State Key Laboratory of Cryospheric Science,Northwest Institute of Eco-Environment and Resources,Chinese Academy of Sciences(CAS),Lanzhou 730000,China [2]University of Chinese Academy of Sciences,Beijing 100049,China [3]College of Earth and Environmental Sciences,Lanzhou University,Lanzhou 730000,China [4]Key Laboratory of Land Surface Process and Climate Change in Cold and Arid Regions,Northwest Institute of Eco-Environment and Resources,CAS,Lanzhou 730000,China [5]Xinjiang Bayingolin Mongolian Autonomous Prefecture Meteorological Bureau,Korla 841000,China

出　　处：《Journal of Environmental Sciences》2023年第9期84-95,共12页环境科学学报（英文版）

基　　金：supported by the Pan-Third Pole Environment Study for a Green Silk Road(Pan-TPE)(No.XDA20040501);the Frontier Science Key Project of CAS(No.QYZDJ-SSW-DQC039);the Gansu Science and Technology Plan(No.18JR2RA005);the CAS“Light of West China”program,and the State Key Laboratory of Cryospheric Science(No.SKLCS-ZZ-2022).

摘　　要：To elucidate the variations in mass concentrations of organic carbon(OC)and black carbon(BC)in PM_(2.5) and their light absorption characteristics in Lanzhou,we conducted one-year online measurements by using a newly developed total carbon analyzer(TCA08)coupled with an aethalometer(AE33)from July 2018 to July 2019.The mean OC and BC concentrations were 6.4±4.4 and 2.0±1.3μg/m^(3),respectively.Clear seasonal variations were observed for both components,with winter having the highest concentrations,followed by autumn,spring,and summer.The diurnal variations of OC and BC concentrations were similar throughout the year,with daily two peaks occurring in the morning and evening,respectively.A relatively low OC/BC ratio(3.3±1.2,n=345)were observed,indicating that fossil fuel combustion was the primary source of the carbonaceous components.This is further substantiated by relatively low biomass burning contribution(f_(biomass):27.1%±11.3%)to BC using aethalometer based measurement though f_(biomass) value which increased significantly in winter(41.6%±5.7%).We estimated a considerable brown carbon(BrC)contribution to the total absorption coefficient(b_(abs))at 370 nm(yearly average of 30.8%±11.1%),with a winter maximum of 44.2%±4.1%and a summer minimum of 19.2%±4.2%.Calculation of the wavelength dependence of total b_(abs) revealed an annual mean AAE_(370-520) value of 4.2±0.5,with slightly higher values in spring and winter.The mass absorption cross-section of BrC also exhibited higher values in winter,with an annual mean of 5.4±1.9 m^(2)/g,reflecting the impact of emissions from increased biomass burning on BrC concentrations.

关 键 词：Black carbon Brown carbon Light absorption Source LANZHOU 

分 类 号：X513[环境科学与工程—环境工程]