Seasonality of carbonaceous aerosol composition and light absorption properties in Karachi, Pakistan

被引：21
作者：
Chen, Pengfei [1 ]
Kang, Shichang [1 ,2 ,3 ]
Gul, Chaman [4 ]
Tripathee, Lekhendra [1 ]
Wang, Xiaoxiang [1 ]
Hu, Zhaofu [1 ]
Li, Chaoliu [2 ,3 ]
Pu, Tao [1 ]
机构：
[1] Chinese Acad Sci, Northwest Inst Ecoenvironm & Resources, State Key Lab Cryospher Sci, Lanzhou 730000, Peoples R China
[2] CAS Ctr Excellence Tibetan Plateau Earth Sci, Beijing 100101, Peoples R China
[3] Chinese Acad Sci, Key Lab Tibetan Environm Changes & Land Surface P, Inst Tibetan Plateau Res, Beijing 100101, Peoples R China
[4] Nanjing Univ Informat Sci & Technol, Reading Acad, Nanjing 210044, Jiangsu, Peoples R China
来源：
JOURNAL OF ENVIRONMENTAL SCIENCES | 2020年 / 90卷
基金：
中国国家自然科学基金;
关键词：
Air pollution; Organic carbon; Elemental carbon; Light absorption; Pakistan; SOLUBLE ORGANIC-CARBON; HIGH-ALTITUDE SITE; CHEMICAL-COMPOSITION; BLACK CARBON; BROWN CARBON; SOURCE APPORTIONMENT; OPTICAL-PROPERTIES; TIBETAN PLATEAU; AMBIENT AIR; ATMOSPHERIC-POLLUTION;
D O I：
10.1016/j.jes.2019.12.006
中图分类号：
X [环境科学、安全科学];
学科分类号：
08 ; 0830 ;
摘要：
Characteristics of carbonaceous aerosol (CA) and its light absorption properties are limited in Karachi, which is one of the most polluted metropolitan cities in South Asia. This study presents a comprehensive measurement of seasonality of CA compositions and mass absorption cross-section (MAC) of elemental carbon (EC) and water-soluble organic carbon (WSOC) in total suspended particles (TSP) collected from February 2015 to March 2017 in the southwest part of Karachi. The average TSP, organic carbon (OC), and EC concentrations were extremely high with values as 391.0 +/- 217.0, 37.2 +/- 28.0, and 8.53 +/- 6.97 mg/m(3), respectively. These components showed clear seasonal variations with high concentrations occurring during fall and winter followed by spring and summer. SO42-, NO3-, K+, and NH4+ showed similar variations with CA, implying the significant influence on atmospheric pollutants from anthropogenic activities. Relatively lower OC/EC ratio (4.20 +/- 2.50) compared with remote regions further indicates fossil fuel combustion as a primary source of CA. Meanwhile, sea salt and soil dust are important contribution sources for TSP. The average MAC of EC (632 nm) and WSOC (365 nm) were 6.56 +/- 2.70 and 0.97 +/- 0.37 m(2)/g, respectively. MACEC is comparable to that in urban areas but lower than that in remote regions, indicating the significant influence of local emissions. MACWSOC showed opposite distribution with EC, further suggesting that OC was significantly affected by local fossil fuel combustion. In addition, dust might be an important factor increasing MACWSOC particularly during spring and summer. (C) 2020 The Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences. Published by Elsevier B.V.
引用
收藏
页码：286 / 296
页数：11
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