scholarly journals Aerosol transport pathways and source attribution in China during the COVID-19 outbreak

2021 ◽  
Vol 21 (20) ◽  
pp. 15431-15445
Author(s):  
Lili Ren ◽  
Yang Yang ◽  
Hailong Wang ◽  
Pinya Wang ◽  
Lei Chen ◽  
...  
Keyword(s):  
Air Quality ◽  
North China Plain ◽  
North China ◽  
Eastern China ◽  
Lower Troposphere ◽  
Aerosol Transport ◽  
Transport Pathways ◽  
The North ◽  
The North China Plain ◽  
Local Emissions

Abstract. Due to the coronavirus disease 2019 (COVID-19) pandemic, human activities and industrial productions were strictly restricted during January–March 2020 in China. Despite the fact that anthropogenic aerosol emissions largely decreased, haze events still occurred. Characterization of aerosol transport pathways and attribution of aerosol sources from specific regions are beneficial to air quality and pandemic control strategies. This study establishes source–receptor relationships in various regions covering all of China during the COVID-19 outbreak based on the Community Atmosphere Model version 5 with Explicit Aerosol Source Tagging (CAM5-EAST). Our analysis shows that PM2.5 burden over the North China Plain between 30 January and 19 February is mostly contributed by local emissions (40 %–66 %). For other regions in China, PM2.5 burden is largely contributed from nonlocal sources. During the most polluted days of the COVID-19 outbreak, local emissions within the North China Plain and eastern China contributed 66 % and 87 % to the increase in surface PM2.5 concentrations, respectively. This is associated with the anomalous mid-tropospheric high pressure at the location of the climatological East Asia trough and the consequently weakened winds in the lower troposphere, leading to the local aerosol accumulation. The emissions outside China, especially those from South Asia and Southeast Asia, contribute over 50 % to the increase in PM2.5 concentration in southwestern China through transboundary transport during the most polluted day. As the reduction in emissions in the near future is desirable, aerosols from long-range transport and unfavorable meteorological conditions are increasingly important to regional air quality and need to be taken into account in clean-air plans.

scholarly journals Aerosol transport pathways and source attribution in China during the COVID-19 outbreak

2021 ◽  
Author(s):  
Lili Ren ◽  
Yang Yang ◽  
Hailong Wang ◽  
Pinya Wang ◽  
Lei Chen ◽  
...  
Keyword(s):  
Air Quality ◽  
North China Plain ◽  
North China ◽  
Control Strategies ◽  
Eastern China ◽  
Lower Troposphere ◽  
Aerosol Transport ◽  
Anthropogenic Aerosol ◽  
Transport Pathways ◽  
Local Emissions

Abstract. Due to the coronavirus disease 2019 (COVID-19) pandemic, human activities and industrial productions were strictly restricted during January–March 2020 in China. Despite the fact that anthropogenic aerosol emissions largely decreased, haze events still occurred. Characterization of aerosol transport pathways and attribution of aerosol sources from specific regions are beneficial to the air quality and pandemic control strategies. This study establishes source-receptor relationships in various regions of China during the COVID-19 outbreak based on the Community Atmosphere Model version 5 with Explicit Aerosol Source Tagging (CAM5-EAST). Our analysis shows that PM2.5 burden over the North China Plain between January 30 and February 19 is largely contributed by local emissions (40–66 %). For other regions in China, PM2.5 burden is largely contributed from non-local sources. During the polluted days of COVID-19 outbreak, local emissions within North China Plain and Eastern China, respectively, contribute 66 % and 87 % to the increase in surface PM2.5 concentrations. This is associated with the anomalous mid-tropospheric high pressure at the location of climatological East Asia trough and the consequently weakened winds in the lower troposphere, leading to the local aerosol accumulation. The emissions outside China, especially from South and Southeast Asia, contribute over 50 % to the increase in PM2.5 concentration in Southwestern China through transboundary transport during the polluted day. As the reduction in emissions in the near future, aerosols from long-range transport together with unfavorable meteorological conditions are increasingly important to regional air quality and need to be taken into account in clean air plans.

scholarly journals Insights into particulate matter pollution in the North China Plain during wintertime: Local contribution or regional transport?

2020 ◽  
Author(s):  
Jiarui Wu ◽  
Naifang Bei ◽  
Yuan Wang ◽  
Xia Li ◽  
Suixin Liu ◽  
...  
Keyword(s):  
Air Quality ◽  
Source Apportionment ◽  
North China Plain ◽  
North China ◽  
Regional Transport ◽  
The North ◽  
The North China Plain ◽  
Haze Event ◽  
Non Local ◽  
Local Emissions

Abstract. Accurate identification and quantitative source apportionment of fine particulate matters (PM2.5) provide an important prerequisite for design and implementation of emission control strategies to reduce PM pollution. Therefore, a source-oriented version of the WRF-Chem model is developed in the study to make source apportionment of PM2.5 in the North China Plain (NCP). A persistent and heavy haze event occurred in the NCP from 05 December 2015 to 04 January 2016 is simulated using the model as a case study to quantify PM2.5 contributions of local emissions and regional transport. Results show that local and non-local emissions contribute 36.3 % and 63.7 % of the PM2.5 mass in Beijing during the haze event on average. When Beijing's air quality is excellent or good in terms of hourly PM2.5 concentrations, local emissions dominate the PM2.5 mass with contributions exceeding 50 %. However, when the air quality is severely polluted, the PM2.5 contribution of non-local emissions is around 75 %. The non-local emissions also dominate the Tianjin's air quality, with average PM2.5 contributions exceeding 70 %. The PM2.5 level in Hebei and Shandong is generally controlled by local emissions, but in Henan, local and non-local emissions play an almost equivalent role in the PM2.5 level, except when the air quality is severely polluted, with non-local PM2.5 contributions of over 60 %. Additionally, the primary aerosol species are generally dominated by local emissions with the average contribution exceeding 50%. However, the source apportionment of secondary aerosols shows more evident regional characteristics. Therefore, except cooperation with neighboring provinces to carry out strict emission mitigation measures, reducing primary aerosols constitutes the priority to alleviate PM pollution in the NCP, especially in Beijing and Tianjin.

How aerosol transport from the North China plain contributes to air quality in northeast China

2020 ◽  
Vol 738 ◽  
pp. 139555 ◽  
Author(s):  
Hujia Zhao ◽  
Huizheng Che ◽  
Lei Zhang ◽  
Ke Gui ◽  
Yanjun Ma ◽  
...  
Keyword(s):  
Air Quality ◽  
Northeast China ◽  
North China Plain ◽  
North China ◽  
Aerosol Transport ◽  
The North ◽  
The North China Plain

scholarly journals Insights into particulate matter pollution in the North China Plain during wintertime: local contribution or regional transport?

2021 ◽  
Vol 21 (3) ◽  
pp. 2229-2249
Author(s):  
Jiarui Wu ◽  
Naifang Bei ◽  
Yuan Wang ◽  
Xia Li ◽  
Suixin Liu ◽  
...  
Keyword(s):  
Particulate Matter ◽  
Air Quality ◽  
Source Apportionment ◽  
North China Plain ◽  
North China ◽  
Regional Transport ◽  
The North ◽  
The North China Plain ◽  
Haze Event ◽  
Local Emissions

Abstract. Accurate identification and quantitative source apportionment of fine particulate matter (PM2.5) provide an important prerequisite for design and implementation of emission control strategies to reduce PM pollution. Therefore, a source-oriented version of the WRF-Chem model is developed in the study to conduct source apportionment of PM2.5 in the North China Plain (NCP). A persistent and heavy haze event that occurred in the NCP from 5 December 2015 to 4 January 2016 is simulated using the model as a case study to quantify PM2.5 contributions of local emissions and regional transport. Results show that local and nonlocal emissions contribute 36.3 % and 63.7 % of the PM2.5 mass in Beijing during the haze event on average. When Beijing's air quality is excellent or good in terms of hourly PM2.5 concentrations, local emissions dominate the PM2.5 mass, with contributions exceeding 50 %. However, when the air quality is severely polluted, the PM2.5 contribution of nonlocal emissions is around 75 %. Nonlocal emissions also dominate Tianjin's air quality, with average PM2.5 contributions exceeding 65 %. The PM2.5 level in Hebei and Shandong is generally controlled by local emissions, but in Henan, local and nonlocal emissions play an almost equivalent role in the PM2.5 level, except when the air quality is severely polluted, with nonlocal PM2.5 contributions of over 60 %. Additionally, the primary aerosol species are generally dominated by local emissions, with the average contribution exceeding 50 %. However, the source apportionment of secondary aerosols shows more evident regional characteristics. Therefore, except for cooperation with neighboring provinces to carry out strict emission mitigation measures, reducing primary aerosols is a priority to alleviate PM pollution in the NCP, especially in Beijing and Tianjin.

scholarly journals A new approach to estimate pollutant emissions based on trajectory modelling and its application in the North China Plain

2011 ◽  
Vol 11 (11) ◽  
pp. 31137-31158 ◽  
Author(s):  
W. Y. Xu ◽  
C. S. Zhao ◽  
P. F. Liu ◽  
L. Ran ◽  
N. Ma ◽  
...  
Keyword(s):  
Air Quality ◽  
North China Plain ◽  
North China ◽  
Pollutant Emissions ◽  
New Approach ◽  
The North ◽  
The North China Plain ◽  
Source Contributions ◽  
Co Emission

Abstract. Emission information is crucial for air quality modelling and air quality management. In this study, a new approach based on the understanding of the relationship between emissions and measured pollutant concentrations has been proposed to estimate pollutant emissions and source contributions. The retrieval can be made with single point in-situ measurements combined with backward trajectory analyses. The method takes into consideration the effect of meteorology on pollutant transport when evaluating contributions and is independent of energy statistics, therefore can provide frequent updates on emission information. The spatial coverage can be further improved by using measurements from several sites and combining the derived emission fields. The method was applied to yield the source distributions of black carbon (BC) and CO in the North China Plain (NCP) using in-situ measurements from the HaChi (Haze in China) Campaign and to evaluate contributions from specific areas to local concentrations at the measurement site. Results show that this method can yield a reasonable emission field for the NCP and can directly quantify areal source contributions. Major BC and CO emission source regions are Beijing, the western part of Tianjin and Langfang, Hebei, with Tangshan being an additional important CO emission source area. The source contribution assessment suggests that, aside from local emissions in Wuqing, Tianjin and Hebei S, SW (d < 100 km) are the greatest contributors to measured local concentrations, while emissions from Beijing contribute little during summertime.

scholarly journals Measurement report: Evaluation of sources and mixing state of black carbon aerosol under the background of emission reduction in the North China Plain: implications for radiative effect

2020 ◽  
Author(s):  
Qiyuan Wang ◽  
Li Li ◽  
Jiamao Zhou ◽  
Jianhuai Ye ◽  
Wenting Dai ◽  
...  
Keyword(s):  
Air Quality ◽  
Solid Fuel ◽  
Emission Reduction ◽  
North China Plain ◽  
North China ◽  
Fossil Fuel ◽  
Radiative Effect ◽  
The North ◽  
The North China Plain ◽  
Fuel Source

Abstract. Accurate understanding of sources and mixing state of black carbon (BC) aerosol is essential for assessing its impacts on air quality and climatic effect. Here, a winter campaign (December 2017–January 2018) was conducted in the North China Plain (NCP) to evaluate the sources, coating composition, and radiative effect of BC under the background of emission reduction since 2013. Results show that liquid fossil fuel source (i.e., traffic emission) and solid fuel source (i.e., biomass and coal burning) contributed 69 % and 31 % to the total BC mass, respectively, using a multiwavelength optical approach combined with the source-based aerosol absorption Ångström exponent values. The air quality model indicates that local emission was the dominant contributor to BC at the measurement site on average, however, emissions in the NCP exerted a critical role for high BC episode. Six classes of BC-containing particles were identified, including (1) BC coated by organic carbon and sulphate (52 % of total BC-containing particles), (2) BC coated by Na and K (24 %), (3) BC coated by K, sulphate, and nitrate (17 %), (4) BC associated with biomass burning (6 %), (5) Pure-BC (1 %), and (6) others (1 %). Different BC sources had distinct impacts on those BC-containing particles. A radiative transfer model estimated that the amount of BC detected can produce an atmospheric forcing of +18.0 W m−2 and a heating rate of 0.5 K day−1. Results presented herein highlight that further reduction of solid fuel combustion-related BC may be a more effective way to mitigate regional warming in the NCP, although larger BC contribution was from liquid fossil fuel source.

scholarly journals Investigations of temporal and spatial distribution of precursors SO<sub>2</sub> and NO<sub>2</sub> vertical columns in the North China Plain using mobile DOAS

2018 ◽  
Vol 18 (3) ◽  
pp. 1535-1554 ◽  
Author(s):  
Fengcheng Wu ◽  
Pinhua Xie ◽  
Ang Li ◽  
Fusheng Mou ◽  
Hao Chen ◽  
...  
Keyword(s):  
Spatial Distribution ◽  
Air Quality ◽  
North China Plain ◽  
North China ◽  
Emission Sources ◽  
Temporal And Spatial Distribution ◽  
Air Mass ◽  
The North ◽  
The North China Plain ◽  
Temporal And Spatial

Abstract. Recently, Chinese cities have suffered severe events of haze air pollution, particularly in the North China Plain (NCP). Investigating the temporal and spatial distribution of pollutants, emissions, and pollution transport is necessary to better understand the effect of various sources on air quality. We report on mobile differential optical absorption spectroscopy (mobile DOAS) observations of precursors SO2 and NO2 vertical columns in the NCP in the summer of 2013 (from 11 June to 7 July) in this study. The different temporal and spatial distributions of SO2 and NO2 vertical column density (VCD) over this area are characterized under various wind fields. The results show that transport from the southern NCP strongly affects air quality in Beijing, and the transport route, particularly SO2 transport on the route of Shijiazhuang–Baoding–Beijing, is identified. In addition, the major contributors to SO2 along the route of Shijiazhuang–Baoding–Beijing are elevated sources compared to low area sources for the route of Dezhou–Cangzhou–Tianjin–Beijing; this is found using the interrelated analysis between in situ and mobile DOAS observations during the measurement periods. Furthermore, the discussions on hot spots near the city of JiNan show that average observed width of polluted air mass is 11.83 and 17.23 km associated with air mass diffusion, which is approximately 60 km away from emission sources based on geometrical estimation. Finally, a reasonable agreement exists between the Ozone Monitoring Instrument (OMI) and mobile DOAS observations, with a correlation coefficient (R2) of 0.65 for NO2 VCDs. Both datasets also have a similar spatial pattern. The fitted slope of 0.55 is significantly less than unity, which can reflect the contamination of local sources, and OMI observations are needed to improve the sensitivities to the near-surface emission sources through improvements of the retrieval algorithm or the resolution of satellites.

scholarly journals Distribution and Sources of Air pollutants in the North China Plain Based on On-Road Mobile Measurements

2016 ◽  
Author(s):  
Yi Zhu ◽  
Jiping Zhang ◽  
Junxia Wang ◽  
Wenyuan Chen ◽  
Yiqun Han ◽  
...  
Keyword(s):  
Air Pollutants ◽  
Ultrafine Particles ◽  
North China Plain ◽  
North China ◽  
Regional Transport ◽  
Large Cities ◽  
Model Studies ◽  
The North ◽  
The North China Plain ◽  
Local Emissions

Abstract. The North China Plain (NCP) has been experiencing severe air pollution problems with rapid economic growth and urbanisation. Many field and model studies have examined the distribution of air pollutants in the NCP, but convincing results have not been achieved mainly due to a lack of direct measurements of pollutants over large areas. Here, we employed a mobile laboratory to observe the main air pollutants in a large part of the NCP from June 11 to July 15, 2013. High median concentrations of sulphur dioxide (SO2) (12 ppb), nitrogen oxides (NOx) (NO + NO2; 452 ppb), carbon monoxide (CO) (956 ppb), black carbon (BC; 5.5 μg m−3) and ultrafine particles (28 350 cm−3) were measured. Most of the high values, i.e., 95 percentile concentrations, were distributed near large cities, suggesting the influence of local emissions. In addition, we analysed the regional transport of SO2 and CO, relatively long-lived pollutants, based on our mobile observations together with wind field and satellite data analyses. Our results suggested that, for border areas of the NCP, wind from outside would have a diluting effect on pollutants, while south winds would bring in pollutants accumulated during transport through other parts of the NCP. For the central NCP, the concentrations of pollutants were likely to remain at high levels, partly due to the influence of regional transport by prevalent south–north winds over the NCP and partly by local emissions.

scholarly journals Uplifting of carbon monoxide from biomass burning and anthropogenic sources to the free troposphere in East Asia

2015 ◽  
Vol 15 (5) ◽  
pp. 2843-2866 ◽  
Author(s):  
K. Ding ◽  
J. Liu ◽  
A. Ding ◽  
Q. Liu ◽  
T. L. Zhao ◽  
...  
Keyword(s):  
East Asia ◽  
Forest Fires ◽  
North China Plain ◽  
North China ◽  
Anthropogenic Sources ◽  
Free Troposphere ◽  
Transport Pathways ◽  
Upper Troposphere ◽  
The North ◽  
The North China Plain

Abstract. East Asia has experienced rapid development with increasing carbon monoxide (CO) emission in the past decades. Therefore, uplifting CO from the boundary layer to the free troposphere in East Asia can have great implications on regional air quality around the world. It can also influence global climate due to the longer lifetime of CO at higher altitudes. In this study, three cases of high CO episodes in the East China Sea and the Sea of Japan from 2003 to 2005 are examined with spaceborne Measurements of Pollution in the Troposphere (MOPITT) data, in combination with aircraft measurements from the Measurement of Ozone and Water Vapor by Airbus In-Service Aircraft (MOZAIC) program. High CO abundances of 300–550 ppbv are observed in MOZAIC data in the free troposphere during these episodes. These are among the highest CO abundances documented at these altitudes. On average, such episodes with CO over 400 ppbv (in the 2003 and 2004 cases) and between 200 and 300 ppbv (in the 2005 case) may occur 2–5 and 10–20% in time, respectively, in the respective altitudes over the region. Correspondingly, elevated CO is shown in MOPITT daytime data in the middle to upper troposphere in the 2003 case, in the lower to middle troposphere in the 2004 case, and in the upper troposphere in the 2005 case. Through analyses of the simulations from a chemical transport model GEOS-Chem and a trajectory dispersion model FLEXPART, we found different CO signatures in the elevated CO and distinct transport pathways and mechanisms for these cases. In the 2003 case, emissions from large forest fires near Lake Baikal dominated the elevated CO, which had been rapidly transported upward by a frontal system from the fire plumes. In the 2004 case, anthropogenic CO from the North China Plain experienced frontal lifting and mostly reached ~ 700 hPa near the East China Sea, while CO from biomass burning over Indochina experienced orographic lifting, lee-side-trough-induced convection, and frontal lifting through two separate transport pathways, leading to two distinct CO enhancements around 700 and 300 hPa. In the 2005 case, the observed CO of ~ 300 ppbv around 300 hPa originated from anthropogenic sources over the Sichuan Basin and the North China Plain and from forest fires over Indochina. The high CO was transported to such altitudes through strong frontal lifting, interacting with convection and orographic lifting. These cases show that topography affects vertical transport of CO in East Asia via different ways, including orographic uplifting over the Hengduan Mountains, assisting frontal lifting in the North China Plain, and facilitating convection in the Sichuan Basin. In particular, topography-induced lee-side troughs over Indochina led to strong convection that assisted CO uplifting to the upper troposphere. This study shows that the new daytime MOPITT near-infrared (NIR) and thermal-infrared (TIR) data (version 5 or above) have enhanced vertical sensitivity in the free troposphere and may help qualitative diagnosis of vertical transport processes in East Asia.

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