Research

19 pages, 349 KiB

Open AccessArticle

Smog Pollution, Environmental Uncertainty, and Operating Investment

by Bin Li, Hanxuan Shi, David C. Yang and Muze Peng

Atmosphere 2021, 12(11), 1378; https://doi.org/10.3390/atmos12111378 - 21 Oct 2021

Cited by 3 | Viewed by 3162

Smog pollution in China has drawn worldwide attention. Using companies’ data from Chinese Securities Markets and Accounting Research database (CSMAR) and air quality monitoring data from China National Environmental Monitoring Centre(CNEMC), we employ the PM_2.5 concentration as a proxy for smog pollution [...] Read more.

Smog pollution in China has drawn worldwide attention. Using companies’ data from Chinese Securities Markets and Accounting Research database (CSMAR) and air quality monitoring data from China National Environmental Monitoring Centre(CNEMC), we employ the PM_2.5 concentration as a proxy for smog pollution and examine the effect of smog pollution on company environmental uncertainty and operating investment in 74 key cities in China. The empirical results show that smog pollution causes an increase in company environmental uncertainty and a decrease in operating investment for Chinese listed companies, with environmental uncertainty as a mediating variable. Smog pollution can positively influence companies’ environmental uncertainty through their employees and high pressure from the public and government. According to the real-options-based investment approach, companies choose to “wait and see” and, correspondingly, reduce operating investment under high environmental uncertainty such as that caused by smog pollution. Additionally, we find that state-owned enterprises are more significantly influenced by smog pollution in terms of environmental uncertainty and operating investment because of their close relationships with the government and their responsibility to set an example among Chinese companies in the fight against smog pollution. Full article

(This article belongs to the Special Issue Aerosol Pollution in Asia)

14 pages, 6480 KiB

Open AccessArticle

Particulate PAH Transport Associated with Adult Chronic Cough Occurrence Closely Connected with Meteorological Conditions: A Modelling Study

by Yayoi Inomata, Masato Takeda, Nguyen Thao, Mizuo Kajino, Takafumi Seto, Hiroyuki Nakamura and Kazuichi Hayakawa

Atmosphere 2021, 12(9), 1163; https://doi.org/10.3390/atmos12091163 - 10 Sep 2021

Cited by 2 | Viewed by 1467

Abstract

Exposure to polycyclic aromatic hydrocarbons (PAHs) are a cause of chronic cough occurrence in adult patients. In order to clear the relationship between transboundary transport of PAH and health effects, this study investigates the relationship between atmospheric particulate PAHs (p-PAHs), cough occurrence by [...] Read more.

Exposure to polycyclic aromatic hydrocarbons (PAHs) are a cause of chronic cough occurrence in adult patients. In order to clear the relationship between transboundary transport of PAH and health effects, this study investigates the relationship between atmospheric particulate PAHs (p-PAHs), cough occurrence by epidemiological research, and meteorological conditions using a chemical transport model. Source receptor relationship (SRR) analysis revealed that a higher cough occurrence was caused by exposure to high p-PAH levels in air masses transported from central China (CCHN, 30–40° N) under westerly conditions. The p-PAHs transported from northern China (NCHN, >40° N) and the eastern part of Russia (ERUS) under north-westerly conditions also contributed to cough occurrence. The low equivalent potential temperature (ePT) and geopotential height anomaly suggested that the p-PAHs emitted near the surface were suppressed to upward transport under the colder air mass but were instead transported horizontally near the surface in the boundary layer, resulting in high p-PAH concentrations arriving in Kanazawa. Our study’s findings suggest that the air mass transport pattern associated with meteorology strongly influences the high p-PAH concentrations causing adult chronic cough occurrence. Full article

(This article belongs to the Special Issue Aerosol Pollution in Asia)

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17 pages, 435 KiB

Open AccessEditor’s ChoiceArticle

The Impact of Smog Pollution on Audit Quality: Evidence from China

by Bin Li, Ying Zhou, Tingyu Zhang and Yang Liu

Atmosphere 2021, 12(8), 1015; https://doi.org/10.3390/atmos12081015 - 07 Aug 2021

Cited by 4 | Viewed by 2352

Abstract

Audit quality usually refers to the quality that the auditing services accounting firm auditors provide to an enterprise in the form of an audit report. This study empirically analyzes the impact mechanism of smog pollution on audit quality, based on the data of [...] Read more.

Audit quality usually refers to the quality that the auditing services accounting firm auditors provide to an enterprise in the form of an audit report. This study empirically analyzes the impact mechanism of smog pollution on audit quality, based on the data of A-share listed companies in the Shanghai and Shenzhen Stock Exchanges during the period 2013 to 2017 and the air quality monitoring data released by the China National Environmental Monitoring Centre covering the period 2013 to 2018. First, the empirical results show that smog pollution can lead to a decline in audit quality. Second, audit time plays a partial mediating role in the relationship between smog pollution and audit quality. Further analysis indicates that the negative impact of smog pollution on audit quality and the intermediary role played by audit time are only significant in the sample of “top 10” accounting firms. Third, the enterprise′s internal control level positively moderates the mediating effect of audit time on smog pollution and audit quality. Full article

(This article belongs to the Special Issue Aerosol Pollution in Asia)

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16 pages, 1167 KiB

Open AccessArticle

Secondary Organic Aerosols in PM_2.5 in Bengbu, a Typical City in Central China: Concentration, Seasonal Variation and Sources

by Shiwei Zhang, Hao Tang, Qing Li, Liang Li, Chaojun Ge, Li Li and Jialiang Feng

Atmosphere 2021, 12(7), 854; https://doi.org/10.3390/atmos12070854 - 30 Jun 2021

Cited by 8 | Viewed by 2016

Abstract

To investigate the concentration, seasonal variation, and sources of secondary organic aerosols (SOAs) in the inland areas of central China, 244 seasonal PM_2.5 samples were collected from January to October 2019 at one urban site and one suburban site simultaneously in Bengbu [...] Read more.

To investigate the concentration, seasonal variation, and sources of secondary organic aerosols (SOAs) in the inland areas of central China, 244 seasonal PM_2.5 samples were collected from January to October 2019 at one urban site and one suburban site simultaneously in Bengbu of Anhui Province. Concentrations of organic carbon (OC), elemental carbon (EC), water-soluble organic carbon (WSOC), and typical organic tracers, including saccharides, tracers of SOAs from isoprene, terpenes, and toluene, were measured. Results showed that Bengbu has high pollution levels of organic aerosols, with annual average OC concentrations of about 9.5 μg m⁻³. About 60% of the OC in PM_2.5 in Bengbu was water soluble. Different seasonal trends were found for the SOA tracers of isoprene, monoterpene, seisquiterpene, and toluene. The highest seasonal average concentration of the isoprene SOA tracers was observed in summer and of the monoterpene and seisquiterpene SOA tracers in autumn. A stronger correlation was found between the 2-methylglyceric acid-to-2-methyltetrol ratio (MGA/MTL) and ambient temperature than that between MGA/MTLs and NO_X concentration, suggesting that temperature has an important impact on the MGA/MTL ratio besides NO_X concentration. The OC/EC-based method, WSOC-based method, tracer yield method, and positive matrix factorization (PMF)-based method were used to estimate the concentration and sources of secondary organic carbon (SOC), and the PMF-based method was believed to be able to give reasonable results. SOC was the main contributor of WSOC in PM_2.5 in Bengbu, while biomass burning made an important contribution to WSOC in autumn and winter (~40%). SOC was mainly associated with SOA tracers in summer and mainly associated with secondary ions in spring and winter, suggesting different formation mechanisms in different seasons. Full article

(This article belongs to the Special Issue Aerosol Pollution in Asia)

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11 pages, 2458 KiB

Open AccessArticle

Characteristics of Aerosol and Effect of Aerosol-Radiation-Feedback in Handan, an Industrialized and Polluted City in China in Haze Episodes

by Sen Yao, Qianheng Wang, Junmei Zhang and Ruinan Zhang

Atmosphere 2021, 12(6), 670; https://doi.org/10.3390/atmos12060670 - 24 May 2021

Cited by 4 | Viewed by 1876

Abstract

In order to investigate the chemical characteristics of aerosol pollution including PM₁ and PM_2.5 in Handan, the offline sampling campaign was conducted and the concentrations of total water-soluble inorganic ions (TWSI), carbonaceous components (OC and EC) were analyzed. The average concentrations [...] Read more.

In order to investigate the chemical characteristics of aerosol pollution including PM₁ and PM_2.5 in Handan, the offline sampling campaign was conducted and the concentrations of total water-soluble inorganic ions (TWSI), carbonaceous components (OC and EC) were analyzed. The average concentrations were 88.5 μg/m³ for PM₁ and 122 μg/m³ for PM_2.5, and the corresponding ratios of PM₁ versus PM_2.5 on non-pollution, mild-moderate pollution and heavy pollution were 0.67, 0.70 and 0.77, respectively. TWSI and OC accounted for 43.2% and 15.4% in PM₁, 41.8% and 16.0% in PM_2.5. Secondary components in PM_2.5 and PM₁ increased with heavy pollution, SNA (SO₄²⁻, NO₃⁻ and NH₄⁺) was enriched in PM₁ but SOC (Secondary Organic Carbon) was more enriched in PM_1–2.5. Furthermore, for evaluating the effect of aerosol feedback the WRF-Chem model was applied to identify the aerosol-radiation interaction of aerosol feedback influence on the PM_2.5 concentration and various meteorological factors in Handan. The results indicated that the aerosol radiative effects will result in an average 32.62%(36.18 W/m²) decrease in downward short wave flux at ground surface (SWDOWN), an average 17.52% (39.15 m) and 0.16% (0.44 K) decrease in planetary boundary layer height(PBLH) and surface temperature (T2). The wind speed at 10 m (WS) and relative humidity (RH) will be increased by about 4.16%(0.11 m/s) and 1.89% (0.78%), respectively. Full article

(This article belongs to the Special Issue Aerosol Pollution in Asia)

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13 pages, 6407 KiB

Open AccessArticle

Ensemble Dispersion Simulation of a Point-Source Radioactive Aerosol Using Perturbed Meteorological Fields over Eastern Japan

by Tsuyoshi Thomas Sekiyama, Mizuo Kajino and Masaru Kunii

Atmosphere 2021, 12(6), 662; https://doi.org/10.3390/atmos12060662 - 22 May 2021

Cited by 3 | Viewed by 1898

Abstract

We conducted single-model initial-perturbed ensemble simulations to quantify uncertainty in aerosol dispersion modeling, focusing on a point-source radioactive aerosol emitted from the Fukushima Daiichi Nuclear Power Plant (FDNPP) in March 2011. The ensembles of the meteorological variables were prepared using a data assimilation [...] Read more.

We conducted single-model initial-perturbed ensemble simulations to quantify uncertainty in aerosol dispersion modeling, focusing on a point-source radioactive aerosol emitted from the Fukushima Daiichi Nuclear Power Plant (FDNPP) in March 2011. The ensembles of the meteorological variables were prepared using a data assimilation system that consisted of a non-hydrostatic weather-forecast model with a 3-km horizontal resolution and a four-dimensional local ensemble transform Kalman filter (4D-LETKF) with 20 ensemble members. The emission of radioactive aerosol was not perturbed. The weather and aerosol simulations were validated with in-situ measurements at Hitachi and Tokai, respectively, approximately 100 km south of the FDNPP. The ensemble simulations provided probabilistic information and multiple case scenarios for the radioactive aerosol plumes. Some of the ensemble members successfully reproduced the arrival time and intensity of the radioactive aerosol plumes, even when the deterministic simulation failed to reproduce them. We found that a small ensemble spread of wind speed produced large uncertainties in aerosol concentrations. Full article

(This article belongs to the Special Issue Aerosol Pollution in Asia)

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24 pages, 6660 KiB

Open AccessArticle

“Military Parade Blue Skies” in Beijing: Decisive Influence of Meteorological Factors on Transport Channel and Atmospheric Pollutant Concentration Level

by Shujian Yang, Yang Zhang, Jing Shang, Zhengqiang Li, Benjamin de Foy, James Jay Schauer and Yuanxun Zhang

Atmosphere 2021, 12(5), 636; https://doi.org/10.3390/atmos12050636 - 17 May 2021

Cited by 1 | Viewed by 1939

Abstract

The severity of high atmospheric pollution has been a major social problem in northern China. To improve the air quality in the Beijing–Tianjin–Hebei (BTH) region and guarantee a suitable environment during the military parade and other celebrating activities for the 70th anniversary of [...] Read more.

The severity of high atmospheric pollution has been a major social problem in northern China. To improve the air quality in the Beijing–Tianjin–Hebei (BTH) region and guarantee a suitable environment during the military parade and other celebrating activities for the 70th anniversary of the victory for anti-Fascist Warcraft in the year 2015, a series of strict air quality control policies were carried out. To analyze the reduction extents of PM_2.5 and organic matter components during the control period and to examine the meteorological conditions in this region and their decisive influence on the air quality, PM_2.5 samples were collected and the Lagrangian particle dispersion model FLEXPART was performed to calculate potential source locations within the BTH region. PM_2.5, organic carbon (OC), elementary carbon (EC), and three species types were specifically analyzed. Although the results showed that PM_2.5, OC, and EC reduced by 64.55%, 48.74%, and 60.75% during the control period, the air mass transport patterns showed great difference at certain periods, which altered the dominant transport direction of air mass and the potential source region of pollutants and organic matters. This alteration completely changed major atmospheric pollutants sources contribution and caused huge concentration changes. Parallel cases also showed that meteorological conditions could avoid massive atmospheric transported from a major emission source region to a receptor site. The meteorological conditions changed the main contribution source region in control and non-control periods and proved the air quality control measures were less necessary in some southern Hebei cities during special events periods. Full article

(This article belongs to the Special Issue Aerosol Pollution in Asia)

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17 pages, 8428 KiB

Open AccessArticle

Nocturnal Boundary Layer Evolution and Its Impacts on the Vertical Distributions of Pollutant Particulate Matter

by Yu Shi, Lei Liu, Fei Hu, Guangqiang Fan and Juntao Huo

Atmosphere 2021, 12(5), 610; https://doi.org/10.3390/atmos12050610 - 07 May 2021

Cited by 3 | Viewed by 2276

Abstract

To investigate the evolution of the nocturnal boundary layer (NBL) and its impacts on the vertical distributions of pollutant particulates, a combination of in situ observations from a large tethered balloon, remote sensing instruments (aerosol lidar and Doppler wind lidar) and an atmospheric [...] Read more.

To investigate the evolution of the nocturnal boundary layer (NBL) and its impacts on the vertical distributions of pollutant particulates, a combination of in situ observations from a large tethered balloon, remote sensing instruments (aerosol lidar and Doppler wind lidar) and an atmospheric environment-monitoring vehicle were utilized. The observation site was approximately 100 km southwest of Beijing, the capital of China. Results show that a considerable proportion of pollutant particulates were still suspended in the residual layer (RL) (e.g., the nitrate concentration reached 30 μg m⁻³) after sunset. The NBL height calculated by the aerosol lidar was closer to the top of the RL before midnight because of the pollutants stored aloft in the RL and the shallow surface inversion layer; after midnight, the NBL height was more consistent with the top of the surface inversion layer. As the convective mixing layer gradually became established after sunrise the following day, the pollutants stored in the nocturnal RL of the preceding night were entrained downward into the mixing layer. The early morning PM_2.5 concentration near 700 m in the RL on 20 December decreased by 83% compared with the concentration at 13:34 on 20 December at the same height. The nitrate concentration also decreased significantly in the RL, and the mixing down of nitrate from the RL could contribute about 37% to the nitrate in the mixing layer. Turbulence activities still existed in the RL with the bulk Richardson number (Rb) below the threshold value. The corresponding increase in PM_2.5 was likely to be correlated with the weak turbulence in the RL in the early morning. Full article

(This article belongs to the Special Issue Aerosol Pollution in Asia)

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22 pages, 2681 KiB

Open AccessArticle

Double High-Level Ozone and PM_2.5 Co-Pollution Episodes in Shanghai, China: Pollution Characteristics and Significant Role of Daytime HONO

by Kejing Yang, Lingdong Kong, Songying Tong, Jiandong Shen, Lu Chen, Shengyan Jin, Chao Wang, Fei Sha and Lin Wang

Atmosphere 2021, 12(5), 557; https://doi.org/10.3390/atmos12050557 - 26 Apr 2021

Cited by 18 | Viewed by 2796

Abstract

In recent years, high fine particulate (PM_2.5) pollution episodes with high ozone (O₃) levels have been observed in Shanghai from time to time. However, their occurrence and characteristics remain poorly understood. Meanwhile, as a major precursor of tropospheric hydroxyl [...] Read more.

In recent years, high fine particulate (PM_2.5) pollution episodes with high ozone (O₃) levels have been observed in Shanghai from time to time. However, their occurrence and characteristics remain poorly understood. Meanwhile, as a major precursor of tropospheric hydroxyl radical (OH) that initiates the formation of hydroperoxyl and organic peroxy radicals, HONO would inevitably affect the formation of O₃, but its role in the formation of O₃ during the double high-level PM_2.5 and O₃ pollution episodes remains unclear. In this study, the characteristics of the double high pollution episodes and the role of HONO in O₃ formation in these episodes were investigated based on field observation in urban Shanghai from 2014 to 2016. Results showed that high PM_2.5 pollution and high O₃ pollution could occur simultaneously. The cases with data of double high O₃ and PM_2.5 concentrations accounted for about 1.0% of the whole sampling period. During the double high pollution episodes, there still existed active photochemical processes, while the active photochemical processes at high PM_2.5 concentration were conductive to the production and accumulation of O₃ under a VOC-limited regime and a calm atmospheric condition including high temperature, moderately high relative humidity, and low wind speed, which in turn enhanced the conversions of SO₂ and NO₂ and the formation and accumulation of secondary sulfate and nitrate aerosols and further promoted the increase of PM_2.5 concentration and the deterioration of air pollution. Further analysis indicated that the daytime HONO concentration could be strongly negatively correlated with O₃ concentration in most of the double high pollution episodes, revealing the dominant role of HONO in O₃ formation during these pollution episodes. This study provides important field measurement-based evidence for understanding the significant contribution of daytime HONO to O₃ formation, and helps to clarify the formation and coexistence mechanisms of the double high-level O₃ and PM_2.5 pollution episodes. Full article

(This article belongs to the Special Issue Aerosol Pollution in Asia)

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20 pages, 7672 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Comparative Numerical Study of PM_2.5 in Exit-and-Entrance Areas Associated with Transboundary Transport over China, Japan, and Korea

by Cheol-Hee Kim, Fan Meng, Mizuo Kajino, Jaehyun Lim, Wei Tang, Jong-Jae Lee, Yusuke Kiriyama, Jung-Hun Woo, Keiichi Sato, Toshihiro Kitada, Hiroaki Minoura, Jiyoung Kim, Kyoung-Bin Lee, Soona Roh, Hyun-Young Jo and Yu-Jin Jo

Atmosphere 2021, 12(4), 469; https://doi.org/10.3390/atmos12040469 - 08 Apr 2021

Cited by 15 | Viewed by 3128

Abstract

We report the results of year-long PM_2.5 (particulate matter less than 2.5 µm in diameter) simulations over Northeast Asia for the base year of 2013 under the framework of the Long-range Transboundary Air Pollutants in Northeast Asia (LTP) project. LTP is a [...] Read more.

We report the results of year-long PM_2.5 (particulate matter less than 2.5 µm in diameter) simulations over Northeast Asia for the base year of 2013 under the framework of the Long-range Transboundary Air Pollutants in Northeast Asia (LTP) project. LTP is a tripartite project launched by China, Japan, and Korea for cooperative monitoring and modeling of the long-range transport (LRT) of air pollutants. In the modeling aspect in the LTP project, each country’s modeling group employs its own original air quality model and options. The three regional air quality models employed by the modeling groups are WRF-CAMx, NHM-RAQM2, and WRF-CMAQ. PM_2.5 concentrations were simulated in remote exit-and-entrance areas associated with the LRT process over China, Japan, and Korea. The results showed apparent bias that remains unexplored due to a series of uncertainties from emission estimates and inherent model limitations. The simulated PM₁₀ levels at seven remote exit-and-entrance sites were underestimated with the normalized mean bias of 0.4 ± 0.2. Among the four chemical components of PM_2.5 (SO₄²⁻, NO₃⁻, organic carbon (OC), and elemental carbon (EC)), the largest inter-model variability was in OC, with the second largest discrepancy in NO₃⁻. Our simulation results also indicated that under considerable SO₄²⁻ levels, favorable environments for ammonium nitrate formation were found in exit-and-entrance areas between China and Korea, and gas-aerosol partitioning for semi-volatile species of ammonium nitrate could be fully achieved prior to arrival at the entrance areas. Other chemical characteristics, including NO₃⁻/SO₄²⁻ and OC/EC ratios, are discussed to diagnose the LRT characteristics of PM_2.5 in exit-and-entrance areas associated with transboundary transport over China, Japan, and Korea. Full article

(This article belongs to the Special Issue Aerosol Pollution in Asia)

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16 pages, 4443 KiB

Open AccessEditor’s ChoiceArticle

Vertical Characteristics of Pollution Transport in Hong Kong and Beijing, China

by Xin Yang, Wei Qian, Daoyi Gong, Chuanfeng Zhao, Pak-wai Chan, Wei Zhou, Yu Huang, Fang Zhang and Zhigang Li

Atmosphere 2021, 12(4), 457; https://doi.org/10.3390/atmos12040457 - 04 Apr 2021

Cited by 6 | Viewed by 2534

Abstract

Transported pollution plays an important role in the atmospheric environment of eastern China. This study analyzed the characteristics of surface winds at different air quality levels using meteorological station observations of both wind and mass concentrations of particulate matter with aerodynamic diameters <2.5 [...] Read more.

Transported pollution plays an important role in the atmospheric environment of eastern China. This study analyzed the characteristics of surface winds at different air quality levels using meteorological station observations of both wind and mass concentrations of particulate matter with aerodynamic diameters <2.5 μm (PM_2.5) over Hong Kong and Beijing. In recent decades, wind directions at the surface exhibit a similar pattern for both good and poor air quality levels at all three stations, indicating a weak relationship between surface winds and air quality in Hong Kong. However, winds at a height of 1–2 km govern pollution accumulation. This dominant role is illustrated by a sudden change in wind direction within this layer and a simultaneous pollution accumulation stage on 8 January 2014. The controlling influence of winds at 1–2 km on both the deterioration and improvement of air quality is also supported by a distinct vertical wind distribution for all 21 monotonic increasing stages and 17 decreasing stages of PM_2.5. In contrast, air pollution is transported to Beijing throughout the atmospheric layer that extends from the surface to a height of more than 3 km. This key difference may be due to variations in meteorology, topography, and emission sources between Hong Kong and Beijing. The results that layer of 1–2 km in Hong Kong and of surface to 3 km in Beijing is the height where pollution transport is most likely to occur are critical for forecasting severe haze episodes in eastern China. Full article

(This article belongs to the Special Issue Aerosol Pollution in Asia)

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13 pages, 3368 KiB

Open AccessArticle

Contribution of Local and Transboundary Air Pollution to the Urban Air Quality of Fukuoka, Japan

by Ayako Yoshino, Akinori Takami, Keiichiro Hara, Chiharu Nishita-Hara, Masahiko Hayashi and Naoki Kaneyasu

Atmosphere 2021, 12(4), 431; https://doi.org/10.3390/atmos12040431 - 27 Mar 2021

Cited by 13 | Viewed by 3043

Abstract

Transboundary air pollution (TAP) and local air pollution (LAP) influence the air quality of urban areas. Fukuoka, located on the west side of Japan and affected by TAP from the Asian continent, is a unique example for understanding the contribution of LAP and [...] Read more.

Transboundary air pollution (TAP) and local air pollution (LAP) influence the air quality of urban areas. Fukuoka, located on the west side of Japan and affected by TAP from the Asian continent, is a unique example for understanding the contribution of LAP and TAP. Gaseous species and particulate matter (PM) were measured for approximately three weeks in Fukuoka in the winter of 2018. We classified two distinctive periods, LAP and TAP, based on wind speed. The classification was supported by variations in the concentration of gaseous species and by backward trajectories. Most air pollutants, including NOx and PM, were high in the LAP period and low in the TAP period. However, ozone was the exception. Therefore, our findings suggest that reducing local emissions is necessary. Ozone was higher in the TAP period, and the variation in ozone concentration was relatively small, indicating that ozone was produced outside of the city and transported to Fukuoka. Thus, air pollutants must also be reduced at a regional scale, including in China. Full article

(This article belongs to the Special Issue Aerosol Pollution in Asia)

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18 pages, 5508 KiB

Open AccessEditor’s ChoiceArticle

Improved Algorithms for Remote Sensing-Based Aerosol Retrieval during Extreme Biomass Burning Events

by Sonoyo Mukai, Itaru Sano and Makiko Nakata

Atmosphere 2021, 12(3), 403; https://doi.org/10.3390/atmos12030403 - 20 Mar 2021

Cited by 15 | Viewed by 2493

Abstract

This study proposed an aerosol characterization process using satellites for severe biomass burning events. In general, these severely hazy cases are labeled as “undecided” or “hazy.” Because atmospheric aerosols are significantly affected by factors such as air quality, global climate change, local environmental [...] Read more.

This study proposed an aerosol characterization process using satellites for severe biomass burning events. In general, these severely hazy cases are labeled as “undecided” or “hazy.” Because atmospheric aerosols are significantly affected by factors such as air quality, global climate change, local environmental risk, and human and biological health, efficient and accurate algorithms for aerosol retrieval are required for global satellite data processing. Our previous classification of aerosol types was based primarily on near-ultraviolet (UV) data, which facilitated subsequent aerosol retrieval. In this study, algorithms for aerosol classification were expanded to events with serious biomass burning aerosols (SBBAs). Once a biomass burning event is identified, the appropriate radiation simulation method can be applied to characterize the SBBAs. The second-generation global imager (SGLI) on board the Japanese mission JAXA/Global Change Observation Mission-Climate contains 19 channels, including red (674 nm) and near-infrared (869 nm) polarization channels with a high resolution of 1 km. Using the large-scale wildfires in Kalimantan, Indonesia in 2019 as an example, the complementarity between the polarization information and the nonpolarized radiance measurements from the SGLI was demonstrated to be effective in radiation simulations for biomass burning aerosol retrieval. The retrieved results were verified using NASA/AERONET ground-based measurements, and then compared against JAXA/SGLI/L2-version-1 products, and JMA/Himawari-8/AHI observations. Full article

(This article belongs to the Special Issue Aerosol Pollution in Asia)

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17 pages, 6811 KiB

Open AccessArticle

Trends of Aerosol Optical Thickness Using VIIRS S-NPP during Fog Episodes in Pakistan and India

by Muhammad Umar, Salman Atif, Mark L. Hildebrandt, Ali Tahir, Muhammad Azmat and Muhammad Zeeshan

Atmosphere 2021, 12(2), 242; https://doi.org/10.3390/atmos12020242 - 11 Feb 2021

Cited by 2 | Viewed by 2786

Abstract

Aerosol Optical Thickness (AOT) is one of the important parameters for assessing regional and global level of climate change. Fog episodes have considerably increased in south Asia because of environmental factors, and the burning of agricultural residue leads to major social and economic [...] Read more.

Aerosol Optical Thickness (AOT) is one of the important parameters for assessing regional and global level of climate change. Fog episodes have considerably increased in south Asia because of environmental factors, and the burning of agricultural residue leads to major social and economic problems. In present study, Mann-Kendall trend analysis of AOT and active fire events was done, and their significance were assessed using long-term (October 2012–February 2020) remote sensing data derived smog maps. Visible Infrared Imaging Radiometer Suite National Polar Partnership (VIIRS N-PP) was used to map AOT episodes over the northern region of Pakistan and India. Results reveal that AOT displays a significantly decreasing trend over the northern and eastern region of Pakistan and a similar decreasing trend from the Western to Eastern region of India. Furthermore, active fire events have a significantly increasing trend at the Northern region of Pakistan. However, fire events have a significantly decreasing trend over the southern and southeastern region of India. Additionally, statistically significant decreasing trends were observed for AOT over Chakwal (p-value = 0.2, Z_MK = −2.3) and Patiala (p-value = 0.15, Z_MK = −3.2). Fire events have a significantly increasing trend for Dera Ismail Khan (p-value = 0.01, Z_MK = 1.9), Jhang (p-value = 0.01, Z_MK = 1.9), and Chakwal (p-value = 0.01, Z_MK = 1.8), while they are significantly decreasing trend near New Delhi (p-value = 0.2, Z_MK = −0.9), Aligarh (p-value = 0.15, Z_MK = −0.9) and Patiala (p-value = 0.2, Z_MK = −0.8). Full article

(This article belongs to the Special Issue Aerosol Pollution in Asia)

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12 pages, 3547 KiB

Open AccessArticle

Contribution of Regional PM_2.5 Transport to Air Pollution Enhanced by Sub-Basin Topography: A Modeling Case over Central China

by Weiyang Hu, Tianliang Zhao, Yongqing Bai, Lijuan Shen, Xiaoyun Sun and Yao Gu

Atmosphere 2020, 11(11), 1258; https://doi.org/10.3390/atmos11111258 - 22 Nov 2020

Cited by 23 | Viewed by 2456

Abstract

The Twain-Hu basin (THB), covering the lower plain of Hubei and Hunan provinces in Central China, has experienced severe air pollution in recent years. However, the terrain effects of such sub-basin on air quality over the THB have been incomprehensibly understood. A heavy [...] Read more.

The Twain-Hu basin (THB), covering the lower plain of Hubei and Hunan provinces in Central China, has experienced severe air pollution in recent years. However, the terrain effects of such sub-basin on air quality over the THB have been incomprehensibly understood. A heavy PM_2.5 pollution event occurred over the THB during 4–10 January 2019. By using the observations and WRF-Chem simulations, we investigated the underlying mechanisms of sub-basin effects on the air pollution with several sensitivity experiments. Observationally, air pollution in the western THB urban area with an average PM_2.5 concentration of 189.8 μg m⁻³, which was more serious than the eastern urban area with the average PM_2.5 concentration of 106.3 μg m⁻³, reflecting a different influence of topography on air pollution over the THB. Simulation results revealed that the terrain effect can contribute 12.0% to increasing the PM_2.5 concentrations in the western THB, but slightly mitigate the pollution extent in the eastern THB with the contribution of −4.6% to PM_2.5 during the heavy pollution episode. In particular, the sub-basin terrain was conducive to the accumulation of PM_2.5 by regional transport with the contribution of 39.1 %, and contrarily lowered its local pollution by −57.0% via the enhanced atmospheric boundary layer height and ventilation coefficients. Given a heavy air pollution episode occurring over the THB, such inverse contribution of terrain effects reflected a unique importance of sub-basin topography in regional transport of air pollutants for air pollution in central China. Full article

(This article belongs to the Special Issue Aerosol Pollution in Asia)

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16 pages, 7167 KiB

Open AccessArticle

Analysis of Weather Patterns Related to Wintertime Particulate Matter Concentration in Seoul and a CMIP6-Based Air Quality Projection

by Sang-Hoon Kwon, Jinwon Kim, Sungbo Shim, Jeongbyn Seo and Young-Hwa Byun

Atmosphere 2020, 11(11), 1161; https://doi.org/10.3390/atmos11111161 - 27 Oct 2020

Cited by 5 | Viewed by 2578

Abstract

This study analyzes the relationship between various atmospheric fields and the observed PM₁₀ concentrations in the Seoul metropolitan area, South Korea, during the winters of the 2001–2014 period to find suitable atmospheric indices for predicting high PM₁₀ episodes in the region. [...] Read more.

This study analyzes the relationship between various atmospheric fields and the observed PM₁₀ concentrations in the Seoul metropolitan area, South Korea, during the winters of the 2001–2014 period to find suitable atmospheric indices for predicting high PM₁₀ episodes in the region. The analysis shows that PM₁₀ concentration in the metropolitan area is mainly affected by the intensity of horizontal ventilation and the 500 hPa high-pressure system over the Korean peninsula. The modified Korea particulate matter index (MKPI) is proposed based on a 10 m wind speed for surface ventilation and 500 hPa zonal wind for the intensity of a 500 hPa high-pressure system over the Korean peninsula. It is found that a positive MKPI value is closely correlated with the occurrence of high PM₁₀ concentration episodes, and hence, can be used as a predictor for high PM₁₀ episodes in the area. A future projection of the MKPI using two three-member general circulation model (GCM) ensembles with four shared socioeconomic pathway (SSP) scenarios in Coupled Model Intercomparison Project Phase 6 (CMIP6) shows that positive MKPI events and high PM₁₀ episodes are expected to increase by 5.4−16.4% depending on the SSP scenarios in the 2081−2100 period from the present-day period of 1995−2014. Full article

(This article belongs to the Special Issue Aerosol Pollution in Asia)

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17 pages, 2110 KiB

Open AccessArticle

Investigating the Impacts of Urbanization on PM_2.5 Pollution in the Yangtze River Delta of China: A Spatial Panel Data Approach

by Liang Cheng, Ting Zhang, Longqian Chen, Long Li, Shangjiu Wang, Sai Hu, Lina Yuan, Jia Wang and Mingxin Wen

Atmosphere 2020, 11(10), 1058; https://doi.org/10.3390/atmos11101058 - 04 Oct 2020

Cited by 27 | Viewed by 3426

Abstract

Urbanization is a key determinant of fine particulate matter (PM_2.5) pollution variability. However, there is a limited understanding of different urbanization factors’ roles in PM_2.5 pollution. Using satellite-derived PM_2.5 data from 2002 to 2017, we investigated the spatiotemporal evolution [...] Read more.

Urbanization is a key determinant of fine particulate matter (PM_2.5) pollution variability. However, there is a limited understanding of different urbanization factors’ roles in PM_2.5 pollution. Using satellite-derived PM_2.5 data from 2002 to 2017, we investigated the spatiotemporal evolution and the spatial autocorrelation of PM_2.5 pollution in the Yangtze River Delta (YRD) region. Afterwards, the impacts of three urbanization factors (population urbanization, land urbanization and economic urbanization) on PM_2.5 pollution were estimated by a spatial Durbin panel data model (SDM). Obtained results showed that: (i) PM_2.5 pollution was larger in the north than in the south of YRD; (ii) Lianyungang and Yancheng cities had significant increasing trends in PM_2.5 pollution from 2002 to 2017; (iii) the regional median center of PM_2.5 pollution was observed in the Nanjing city, with gradual shifting to the northwest during the 16-year period; (iv) PM_2.5 pollution showed significant and positive spatial autocorrelation and spillover effect; (v) population urbanization contributed more to the increase in PM_2.5 pollution than land urbanization, while economic urbanization had no significant impact. The present study highlights the impacts of three urbanization factors on PM_2.5 pollution which represent valuable and relevant information for air pollution control and urban planning. Full article

(This article belongs to the Special Issue Aerosol Pollution in Asia)

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