Influence of cloud, fog, and high relative humidity during pollution transport events in South Korea: Aerosol properties and PM2.5 variability

Eck, T. F.; Holben, B. N.; Kim, J.; Beyersdorf, A. J.; Choi, Myungje; Lee, S.; Koo, Ja Ho; Giles, D. M.; Schafer, J. S.; Sinyuk, A.; Peterson, David A.; Reid, Jeffrey S.; Arola, Antti; Slutsker, I.; Smirnov, A.; Sorokin, M. G.; Kraft, J.; Crawford, J. H.; Anderson, B. E.; Thornhill, K. L.; Diskin, G. S.; Kim, Sang Woo; Park, Soo‐Jin

doi:10.1016/j.atmosenv.2020.117530

Cited by 42 publications

(37 citation statements)

References 66 publications

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“…The lack of a clear tendency for these two periods provides an important contrast to the gradients across the SMA that characterized the Transport/Haze and Stagnant periods. A similar analysis using both PM 2.5 and AERONET data supports this assessment (Eck et al, 2020).…”

Section: Transboundary Transportsupporting

confidence: 71%

“…The reduced UV is consistent with the extensive cloud cover on May 24 th and 26 th as discussed in Peterson et al (2019). In addition, fog was present over the Yellow Sea west of the SMA (Peterson et al, 2019;Eck et al, 2020). The low clouds and fog early during the Transport/Haze period may have contributed to the observed shift in the fine volume fraction of aerosols towards larger sizes (i.e.…”

Section: Relationships Among Alw Rh and Inorganic Aerosol Mass Fracsupporting

confidence: 69%

“…S4 ). Volume size distributions retrieved from ground-based AERONET remote sensing measurements during the Transport/Haze period were consistent with the DC-8 observations, with both showing enhanced concentrations of large fine mode particles (i.e., enhanced PM 2.5 compared to PM 1 ) ( Eck et al, 2020 ). This raises the question of whether PM 1 composition measurements may be properly used to infer drivers of PM 2.5 variability.…”

Section: Observationssupporting

confidence: 57%

“…This is consistent with the larger differences in CO/CO 2 slopes observed between the BL and LFT during the Transport/Haze period ( Figure 6 ). While a full evaluation of the meteorological factors governing the changes in boundary layer depth are beyond the scope of this paper, the dominant factor driving the low values during the transport period was likely the heavier cloud cover during this period leading to observed reductions in surface insolation and less surface heating to drive mixing ( Eck et al, 2020 ).…”

Section: Observationsmentioning

confidence: 99%

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Investigation of factors controlling PM2.5 variability across the South Korean Peninsula during KORUS-AQ

et al. 2020

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deployed instrumented aircraft and ground-based measurements to elucidate causes of poor air quality related to high ozone and aerosol concentrations in South Korea. This work synthesizes data pertaining to aerosols (specifically, particulate matter with aerodynamic diameters <2.5 micrometers, PM 2.5) and conditions leading to violations of South Korean air quality standards (24-hr mean PM 2.5 < 35 µg m-3). PM 2.5 variability from AirKorea monitors across South Korea is evaluated. Detailed data from the Seoul vicinity are used to interpret factors that contribute to elevated PM 2.5. The interplay between meteorology and surface aerosols, contrasting synoptic-scale behavior vs. local influences, is presented. Transboundary transport from upwind sources, vertical mixing and containment of aerosols, and local production of secondary aerosols are discussed. Two meteorological periods are probed for drivers of elevated PM 2.5. Clear, dry conditions, with limited transport (Stagnant period), promoted photochemical production of secondary organic aerosol from locally emitted precursors. Cloudy humid conditions fostered rapid heterogeneous secondary inorganic aerosol production from local and transported emissions (Transport/Haze period), likely driven by a positive feedback mechanism where water uptake by aerosols increased gas-to-particle partitioning that increased water uptake. Further, clouds reduced solar insolation, suppressing mixing, exacerbating PM 2.5 accumulation in a shallow boundary layer. The combination of factors contributing to enhanced PM 2.5 is challenging to model, complicating quantification of contributions to PM 2.5 from local versus upwind precursors and production. We recommend co-locating additional continuous measurements at a few AirKorea sites across South Korea to help resolve this and other outstanding questions: carbon monoxide/carbon dioxide (transboundary transport tracer), boundary layer height (surface PM 2.5 mixing depth), and aerosol composition with aerosol liquid water (meteorologically-dependent secondary production). These data would aid future research to refine emissions targets to further improve South Korean PM 2.5 air quality.

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Section: Transboundary Transportsupporting

confidence: 71%

Section: Relationships Among Alw Rh and Inorganic Aerosol Mass Fracsupporting

confidence: 69%

Section: Observationssupporting

confidence: 57%

Section: Observationsmentioning

confidence: 99%

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Investigation of factors controlling PM2.5 variability across the South Korean Peninsula during KORUS-AQ

et al. 2020

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“…Despite the importance of economic development, the close relationship between water environment, such as RH, and human society, air quality [10][11][12][13][14], extreme weather [15][16][17], plant growth, and disease transmission [31]. Effective measures are needed to minimize the impact on water resources, such as good urban planning with rational distribution of different functional zones in cites [97], increasing green areas, and low-impact development (i.e., sponge city construction in China) [98].…”

Section: Rapid Decline Of Rh In the Pearl River Deltamentioning

confidence: 99%

Spatiotemporal Variation in Relative Humidity in Guangdong, China, from 1959 to 2017

Liu

Yang

Xing-hu

2020

Water

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Despite the marked influence of relative humidity (RH) on ecosystems and human society, the spatiotemporal pattern of RH is far from clearly understood. This study analyzed the spatiotemporal variation in RH in Guangdong Province, South China, in the period of 1959–2017. The RH data were collected from 74 national standard meteorological stations. The spatiotemporal variation in RH was evaluated using rotate empirical orthogonal function (REOF) zoning, Mann–Kendall test, and wavelet transform methods. Based on the REOF decomposition situation of monthly RH field, Guangdong was divided into six subareas. The annual mean of RH in the whole province was 78.90%. In terms of spatial variation, overall annual mean RH decreased from southwest to northeast in the province. Temporally, annual mean RH showed a declining trend in the last six decades. Particularly, the RH in the Pearl River Delta area declined at the rate of 1.349%/10a. Mann–Kendall tests showed that mutation points of annual mean RH mostly appeared in the 1990s, especially in the early 1990s. Continuous wavelet transforms of annual mean RH displayed that inland subareas have similar cycle characteristics, and the east coast and Pearl River Delta have no significant period in most time domains. The results provide new understanding of RH variation in the last six decades in South China, which is valuable for detecting climate change, monitoring hazardous weather, and predicting future environmental change.

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Distribution and Potential Sources of Surface Aerosol Particles in the Yangtze River Delta Region, China

Shen

Cao

Zhao

2022

CLEAN Soil Air Water

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Based on meteorological and pollution data from January 2017 to December 2019, in this paper the long-term distribution of surface aerosol particles, and the interaction between aerosol pollution and meteorological factors in four cities of the Yangtze River Delta (YRD) region is investigated. The long-term observation shows the law of typical aerosol pollution characteristics. Meteorological factors are significantly different during aerosol-polluted and nonpolluted days. The effect of each meteorological factor on aerosol pollution may vary by different seasons and cities. The changes in meteorological factors are not completely consistent during aerosol fine-mode and coarse-mode polluted days. To distinguish the possible sources of surface aerosol particles, the potential source contribution function and concentration-weighted trajectory models are applied to study transport sources. Based on the detailed analyses, this study will provide a reliable basis for further pollution control in the YRD.

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Influence of cloud, fog, and high relative humidity during pollution transport events in South Korea: Aerosol properties and PM2.5 variability

Cited by 42 publications

References 66 publications

Investigation of factors controlling PM2.5 variability across the South Korean Peninsula during KORUS-AQ

Investigation of factors controlling PM2.5 variability across the South Korean Peninsula during KORUS-AQ

Spatiotemporal Variation in Relative Humidity in Guangdong, China, from 1959 to 2017

Distribution and Potential Sources of Surface Aerosol Particles in the Yangtze River Delta Region, China

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