Measurement report: Characterization of severe spring haze episodes and influences of long-range transport in episodes the Seoul metropolitan area in March 2019

Title
Measurement report: Characterization of severe spring haze episodes and influences of long-range transport in episodes the Seoul metropolitan area in March 2019
Authors
김화진Qi ZhangYele Sun
Keywords
Aerosol; HR-ToF-AMS; long range trasnport; Pb; nitrate; Smog; haze
Issue Date
2020-10
Publisher
Atmospheric chemistry and physics
Citation
VOL 20-11550
Abstract
Severe haze episodes have occurred frequently in the Seoul metropolitan area (SMA) and throughout East Asian countries, especially during winter and early spring. Although notable progress has been attained in understanding these issues, the causes of severe haze formation have not yet been fully investigated. SMA haze is especially difficult to understand, because the area is impacted by both local emissions from anthropogenic and biogenic activities and emissions transported from upwind sources. Here, we investigated the emission sources and formation processes of particulate matter (PM) during three haze episodes measured in early spring of 2019, from 22 February to 2 April, using a high-resolution aerosol mass spectrometer (HR-AMS). Overall, the average concentration of nonrefractory submicron aerosol (NR-PM1) + BC (black carbon) was 35.1  µ g  m− 3, which was composed of 38  % organics, 12  % SO4, 30  % NO3, 13  % NH4, and 5  % BC. The organics had an average oxygen-to-carbon ratio (O∕ C) of 0.52 and an average organic mass to organic carbon ratio (OM∕ OC) of 1.86. Seven distinct sources of organic aerosols (OAs) were identified via positive matrix factorization (PMF) analysis of the HR-AMS data: vehicle-emitted hydrocarbon-like OA (HOA), cooking OA (COA), solid-fuel-burning emitted OA (SFOA), and four different types of oxidized secondary OA with varying oxidation degrees and temporal trends. Of the 40  d of the measurement period, 23 were identified as haze days (daily average: >35  3), during which three severe haze episodes were recorded. In particular, PM1 concentration exceeded 100  3 during the first episode when an alert was issued, and strict emission controls were implemented in the SMA. Our results showed that nitrate dominated during the three haze episodes and accounted for 39&#8201
URI
http://pubs.kist.re.kr/handle/201004/71969
ISSN
1680-7316
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KIST Publication > Article
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