scholarly journals Supplementary material to "Heavy air pollution with the unique “non-stagnant” atmospheric boundary layer in the Yangtze River Middle Basin aggravated by regional transport of PM<sub>2.5</sub> over China"

2019 ◽  
Author(s):  
Chao Yu ◽  
Tianliang Zhao ◽  
Yongqing Bai ◽  
Lei Zhang ◽  
Xingna Yu ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Air Pollution ◽  
Atmospheric Boundary Layer ◽  
Yangtze River ◽  
The Yangtze River ◽  
Regional Transport ◽  
Supplementary Material

scholarly journals Heavy air pollution with a unique “non-stagnant” atmospheric boundary layer in the Yangtze River middle basin aggravated by regional transport of PM<sub>2.5</sub> over China

2020 ◽  
Vol 20 (12) ◽  
pp. 7217-7230 ◽  
Author(s):  
Chao Yu ◽  
Tianliang Zhao ◽  
Yongqing Bai ◽  
Lei Zhang ◽  
Shaofei Kong ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Air Pollution ◽  
Atmospheric Boundary Layer ◽  
Air Pollutants ◽  
Yangtze River ◽  
Temperature Inversion ◽  
Meteorological Conditions ◽  
Air Pollutant ◽  
The Yangtze River ◽  
Regional Transport

Abstract. The regional transport of air pollutants, controlled by emission sources and meteorological factors, results in a complex source–receptor relationship of air pollution change. Wuhan, a metropolis in the Yangtze River middle basin (YRMB) of central China, experienced heavy air pollution characterized by hourly PM2.5 concentrations reaching 471.1 µg m−3 in January 2016. To investigate the regional transport of PM2.5 over central eastern China (CEC) and the meteorological impact on wintertime air pollution in the YRMB area, observed meteorological and other relevant environmental data from January 2016 were analyzed. Our analysis presented noteworthy cases of heavy PM2.5 pollution in the YRMB area with unique “non-stagnant” meteorological conditions of strong northerly winds, no temperature inversion, and additional unstable structures in the atmospheric boundary layer. This unique set of conditions differed from the stagnant meteorological conditions characterized by near-surface weak winds, air temperature inversion, and stable structure in the boundary layer that are typically observed in heavy air pollution over most regions in China. The regional transport of PM2.5 over CEC aggravated PM2.5 levels, thus creating heavy air pollution in the YRMB area. This demonstrates a source–receptor relationship between the originating air pollution regions in CEC and the receiving YRMB region. Furthermore, a backward trajectory simulation using a Flexible Particle dispersion (FLEXPART) Weather Research and Forecasting (WRF) model to integrate the air pollutant emission inventory over China was used to explore the patterns of regional transport of PM2.5 governed by the strong northerly winds in the cold air activity of the East Asian winter monsoon season. It was estimated that the regional transport of PM2.5 from non-local air pollutant emissions contributes more than 65 % of the PM2.5 concentrations to the heavy air pollution in the YRMB region during the study period, revealing the importance of the regional transport of air pollutants over China as a causative factor of heavy air pollution over the YRMB area.

Cold Fronts Transport Features of North China Pollutant over the Yangtze River Delta, China

2021 ◽  
Author(s):  
Duanyang Liu ◽  
Peishu Gu ◽  
Junlong Qian
Keyword(s):  
Air Pollution ◽  
Wind Speed ◽  
Yangtze River ◽  
North China ◽  
Cold Front ◽  
Pollutant Transport ◽  
The Yangtze River ◽  
Backward Trajectory ◽  
Data Set ◽  
Regional Transport

&lt;p&gt;An air pollution process in Jiangsu Province, China on December 22&amp;#8211;23, 2016 is discussed by analyzing various data set, including the meteorological observation data, the reanalysis data from National Centers for Environmental Prediction (NCEP), the Air Quality Index (AQI), the PM&lt;sub&gt;2.5 &lt;/sub&gt;and PM&lt;sub&gt;10&lt;/sub&gt; concentrations data, and the airflow backward trajectory model of National Oceanic and Atmospheric Administration (NOAA). The results show that the air pollution episode was under the background of a medium cold front from the west of the Hetao area, and caused by regional transport of pollutants from North China. The primary pollutant was PM&lt;sub&gt;2.5&lt;/sub&gt; and PM&lt;sub&gt;10&lt;/sub&gt;. The PM&lt;sub&gt;2.5&lt;/sub&gt; and PM&lt;sub&gt;10&lt;/sub&gt; concentrations increase significantly 4&amp;#8211;6 h after the cold front passing and reached the peak in 13&amp;#8211;24 h. The obvious lag phenomena of the rising period and the peak-moment of PM&lt;sub&gt;2.5&lt;/sub&gt; and PM&lt;sub&gt;10&lt;/sub&gt; concentrations were found at the Suzhou, Huai'an, Taizhou and Xuzhou stations, and the maximum of 3h-allobaric, the maximum and average values of the wind speed near the ground were larger one by one at the four stations respectively in the northwestern Jiangsu, north-central Jiangsu, along with the Yangtze river Jiangsu, and southeastern Jiangsu. The period of middle &amp;#8211;heave level pollution in Suzhou was 7&amp;#8211;9 h later than in Huai'an and Taizhou, and was 24 h later than in Xuzhou, because of the lower PM&lt;sub&gt;2.5&lt;/sub&gt; and PM&lt;sub&gt;10&lt;/sub&gt; concentrations at early December 21, the delay of pollutants from upstream, and the larger wind speed from the boundary layer to the surface in southeastern Jiangsu. WRF-Chem model can well reveal the pollutant transport process. The high-value zone has a close relationship with the position of cold front. At 1200 LST on December 22, the cold front reached Xuzhou accompanied by high PM&lt;sub&gt;2.5&lt;/sub&gt; concentration. At 1400 LST on December 22, the cold front advanced to Huai'an. The high PM&lt;sub&gt;2.5&lt;/sub&gt; concentration zone moved south alongside the cold front and covered Xuzhou and Huai'an. Suzhou, far away from the upstream, was less vulnerable to pollutant transport. The high-value did not fell until the northwest wind shifted to the north wind. The backward trajectory analysis of air pollution also indicated that regional transport of pollutants from North China led to the middle &amp;#8211;heave level pollution weather.&lt;/p&gt;

scholarly journals Heavy air pollution with the unique “non-stagnant” atmospheric boundary layer in the Yangtze River Middle Basin aggravated by regional transport of PM<sub>2.5</sub> over China

2019 ◽  
Author(s):  
Chao Yu ◽  
Tianliang Zhao ◽  
Yongqing Bai ◽  
Lei Zhang ◽  
Xingna Yu ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Air Pollution ◽  
Air Pollutants ◽  
Yangtze River ◽  
Eastern China ◽  
Temperature Inversion ◽  
Meteorological Conditions ◽  
Air Pollutant ◽  
Regional Transport ◽  
Central Eastern

Abstract. Regional transport of air pollutants controlled by both emission sources and meteorological factors results in a complex source-receptor relationship of air pollution change. Wuhan, a metropolis in the Yangtze River Middle Basin (YRMB) of central China experienced heavy air pollution characterized by excessive PM2.5 concentrations reaching 471.1 μg m−3 in January 2016. In order to investigate the regional transport of PM2.5 over China and the meteorological impact on wintertime air pollution in the YRMB area, observational meteorological and other relevant environmental data from January 2016 were analyzed. Our analysis presented the noteworthy cases of heavy PM2.5 pollution in the YRMB area with the unique “non-stagnant” meteorological conditions of strong northerly winds, no temperature inversion and additional unstable structures in the atmospheric boundary layer. This unique set of conditions differed from the stagnant meteorological conditions characterized by near-surface weak winds, air temperature inversion, and stable structure in the boundary layer observed in heavy air pollution over most regions in China. The regional transport of PM2.5 over central-eastern China aggravated PM2.5 levels present in the YRMB area, thus demonstrating the source-receptor relationship between the originating air pollution regions in central-eastern China and the receiving YRMB regions. Furthermore, a backward trajectory simulation using FLEXPART-WRF to integrate the air pollutant emission inventory over China was used to explore the patterns of regional transport of PM2.5 governed by the strong northerly winds in the cold air activity of the East Asian winter monsoon over central-eastern China, which contributes markedly to the heavy PM2.5 pollution in the YRMB area. It was estimated that the regional transport of PM2.5 of non-local air pollutant emissions could contribute more than 65 % of the PM2.5 concentrations to the heavy air pollution in the YRMB region during the study period, revealing the importance of the regional transport of air pollutants over central-eastern China in the formation of heavy air pollution over the YRMB region.

The Relationship Between Atmospheric Boundary Layer Structure, Brown Haze, and Air Pollution in Auckland, New Zealand

2021 ◽  
Author(s):  
Hannah Marley ◽  
Kim Dirks ◽  
Andrew Neverman ◽  
Ian McKendry ◽  
Jennifer Salmond
Keyword(s):  
Boundary Layer ◽  
Air Pollution ◽  
New Zealand ◽  
Atmospheric Boundary Layer ◽  
Boundary Layers ◽  
Layer Structure ◽  
High Surface ◽  
Residual Layer ◽  
Pollution Levels ◽  
Haze Formation

&lt;p&gt;&lt;span&gt;&lt;span&gt;A brown air pollution haze that forms over some international cities during the winter has been found to be associated with negative health outcomes and high surface air pollution levels. Previous research has demonstrated a well-established link between the structure of the atmospheric boundary layer (ABL) and surface air quality; however, the degree to which the structure of the ABL influences for formation of local-&lt;/span&gt;&lt;/span&gt;&lt;span&gt;&lt;span&gt;scale&lt;/span&gt;&lt;/span&gt;&lt;span&gt;&lt;span&gt; brown haze is unknown. Using continuous ceilometer data covering seven consecutive winters, we investigate the influence of the structure of the ABL in relation to surface air pollution and brown haze formation over an urban area of complex coastal terrain in the Southern Hemisphere city of Auckland, New Zealand. Our results suggest the depth and evolution of the ABL has a strong influence on severe brown haze formation. When days with severe brown haze are compared with those when brown haze is expected but not observed (based on favorable meteorology and high surface air pollution levels), days with severe brown haze are found to coincide with significantly shallower daytime convective boundary layers (~ 48% lower), and the nights preceding brown haze formation are found to have significantly shallower nocturnal boundary layers (~ 28% lower). On severe brown haze days the growth rate during the morning transition phase from a nocturnal boundary layer to a convective daytime boundary layer is found to be significantly reduced (70 m h&lt;/span&gt;&lt;/span&gt;&lt;sup&gt;&lt;span&gt;&lt;span&gt;-1&lt;/span&gt;&lt;/span&gt;&lt;/sup&gt;&lt;span&gt;&lt;span&gt;) compared to days on which brown haze is expected but not observed (170 m h&lt;/span&gt;&lt;/span&gt;&lt;sup&gt;&lt;span&gt;&lt;span&gt;-1&lt;/span&gt;&lt;/span&gt;&lt;/sup&gt;&lt;span&gt;&lt;span&gt;). Compared with moderate brown haze, severe brown haze conditions are found to be associated with a significantly higher proportion of days with a distinct residual layer present in the ceilometer profiles, suggesting the entrainment of residual layer pollutants may contribute to the severity of the haze. This study illustrates the complex interaction between the ABL structure, air pollution, and the presence of brown haze, and demonstrates the utility of a ceilometer instrument in understanding and predicting the occurrence of brown haze events. &lt;/span&gt;&lt;/span&gt;&lt;/p&gt;

Two Inversion Layers and Their Impacts on PM2.5 Concentration over the Yangtze River Delta, China

2019 ◽  
Vol 58 (11) ◽  
pp. 2349-2362 ◽  
Author(s):  
Yiwen Xu ◽  
Bin Zhu ◽  
Shuangshuang Shi ◽  
Yong Huang
Keyword(s):  
Boundary Layer ◽  
Vertical Distribution ◽  
Rural Area ◽  
Yangtze River ◽  
Layer Structure ◽  
Yangtze River Delta ◽  
Emission Sources ◽  
The Yangtze River ◽  
The Vertical Distribution ◽  
The Yangtze River Delta

AbstractAn integrated winter field campaign was conducted to investigate the atmospheric boundary layer structure and PM2.5 concentration at three sites over the Yangtze River delta (YRD) in China: Shouxian (a rural area), a site in a northern suburb of Nanjing, and Dongshan (a residential area). Two temperature inversion layers and air pollution events occurred simultaneously from 30 to 31 December 2016, local time, over the YRD. It was found that the two inversion layers were related to the presence of a high pressure system, resulting in divergence in the upper boundary layer and radiative cooling near the ground at night. Dominated by agricultural and residential biomass burning, the surface emission sources from the Shouxian rural area were moderately strong. After the formation of the two inversions, the vertical distribution of PM2.5 concentration below the upper inversion layer was uniform as a result of thorough boundary layer mixing in the earlier hours. During nighttime at the Nanjing site, air pollutant plumes from nearby elevated point sources could not easily diffuse downward/upward between the two inversion layers, which led to a distinct peak in the PM2.5 concentration. At the Dongshan site, the emission sources were weak and the nighttime PM2.5 concentration above 100 m was high. The surface PM2.5 concentration gradually increased from early morning to noon, which was attributed to emissions related to the local residents. The results indicated that the vertical distribution of pollutants was affected by a combination of local emissions, vertical boundary layer structure, and horizontal and vertical transports.

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