scholarly journals Intra-regional transport of black carbon between the south edge of the North China Plain and central China during winter haze episodes

2019 ◽  
Vol 19 (7) ◽  
pp. 4499-4516 ◽  
Author(s):  
Huang Zheng ◽  
Shaofei Kong ◽  
Fangqi Wu ◽  
Yi Cheng ◽  
Zhenzhen Niu ◽  
...  
Keyword(s):  
North China Plain ◽  
North China ◽  
Fossil Fuel ◽  
Central China ◽  
The South ◽  
The North ◽  
The North China Plain ◽  
Geographic Origins ◽  
Regional Air Quality ◽  
Pollution Episodes

Abstract. Black carbon (BC), which is formed from the incomplete combustion of fuel sources (mainly fossil fuel, biofuel and open biomass burning), is a chemically inert optical absorber in the atmosphere. It has significant impacts on global climate, regional air quality and human health. During transportation, its physical and chemical characteristics as well as its sources change dramatically. To investigate the properties of BC (i.e., mass concentration, sources and optical properties) during intra-regional transport between the southern edge of the North China Plain (SE-NCP) and central China (CC), simultaneous BC observations were conducted in a megacity (Wuhan – WH) in CC, in three borderline cities (Xiangyang – XY, Suixian – SX and Hong'an – HA; from west to east) between the SE-NCP and CC, and in a city (Luohe – LH) in the SE-NCP during typical winter haze episodes. Using an Aethalometer, the highest equivalent BC (eBC) mass concentrations and the highest aerosol absorption coefficients (σabs) were found in LH in the SE-NCP, followed by the borderline cities (XY, SX and HA) and WH. The levels, sources, optical properties (i.e., σabs and absorption Ångström exponent, AAE) and geographic origins of eBC were different between clean and polluted periods. Compared with clean days, higher eBC levels (26.4 %–163 % higher) and σabs (18.2 %–236 % higher) were found during pollution episodes due to the increased combustion of fossil fuels (increased by 51.1 %–277 %), which was supported by the decreased AAE values (decreased by 7.40 %–12.7 %). The conditional bivariate probability function (CBPF) and concentration-weighted trajectory (CWT) results showed that the geographic origins of biomass burning (BCbb) and fossil fuel (BCff) combustion-derived BC were different. Air parcels from the south dominated for border sites during clean days, with contributions of 46.0 %–58.2 %, whereas trajectories from the northeast showed higher contributions (37.5 %–51.2 %) during pollution episodes. At the SE-NCP site (LH), transboundary influences from the south (CC) exhibited a more frequent impact (with air parcels from this direction comprising 47.8 % of all parcels) on the ambient eBC levels during pollution episodes. At WH, eBC was mainly from the northeast transport route throughout the observation period. Two transportation cases showed that the mass concentrations of eBC, BCff and σabs all increased, from upwind to downwind, whereas AAE decreased. This study highlights that intra-regional prevention and control for dominant sources at each specific site should be considered in order to improve the regional air quality.

scholarly journals Intra-regional transport of black carbon between the south edge of North China Plain and Central China during winter haze episodes

2018 ◽  
Author(s):  
Huang Zheng ◽  
Shaofei Kong ◽  
Fangqi Wu ◽  
Yi Cheng ◽  
Zhenzhen Niu ◽  
...  
Keyword(s):  
Optical Properties ◽  
Air Quality ◽  
Biomass Burning ◽  
North China Plain ◽  
North China ◽  
Fossil Fuel ◽  
Central China ◽  
Geographic Origins ◽  
Regional Air Quality ◽  
Pollution Episodes

Abstract. Black carbon (BC), from the incomplete combustion sources (mainly fossil fuel, biofuel and open biomass burning), is chemically inertness and optical absorbance in the atmosphere. It has significant impacts on global climate, regional air quality, and human health. During the transportation, its physical-chemical characteristics, optical properties and sources would change dramatically. To investigate the BC properties (i.e., mass concentration, sources and optical properties) during the intra-regional transport between the south edge of North China Plain (SE-NCP) and Central China (CC), simultaneous observations of BC at a megacity (Wuhan, WH) in CC, three borderline cities (Xiangyang, XY, Suixian, SX and Hong'an, HA, distributing from the west to east) between SE-NCP and CC and a city (Luohe, LH) in SE-NCP were conducted during the typical winter haze episodes. Using Aethalometer, the highest equivalent BC (eBC) mass concentrations and aerosol absorption coefficients (σabs) were found in the city (LH) at SE-NCP, followed by the borderline cities (XY, SX and HA) and megacity (WH). The levels, sources, optical properties (i.e., σabs and absorption Ångström exponent, AAE) and geographic origins of eBC were different between clean and pollution episodes. Compared to clean days, the higher eBC levels (increased by 26.4–163 %) and σabs (increased by 18.2–236 %) were found during pollution episodes due to more combustion of fossil fuel (contributing for 51.1–277 %), supported by the decreased AAE (by 7.40–12.7 %). Non-parametric wind regression (NWR) and concentration-weighted trajectory (CWT) results showed that the geographic origins of biomass burning (BCbb) and fossil fuel (BCff) combustion derived BC were different. Based on cluster analysis of trajectories, air parcels from south direction dominated for border sites during clean days, with contributions of 46.0–58.2 %, while trajectories from the northeast had higher contributions (37.5–51.2 %) during pollution episodes. At the SE-NCP site (LH), transboundary influences from south direction (CC) exhibited more frequent impact (with the air parcels from this direction contributed 47.8 % of all the parcels) on the ambient eBC levels during pollution episodes. At WH, eBC was mainly from the northeast transport route during the whole observation period. Two transportation cases showed that from upwind to downwind direction, the mass concentrations of eBC, BCbb and BCff all increased, while AAE decreased. This study highlighted that intra-regional prevention and control for dominated sources of specific sites should be considered to improve the regional air quality.

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 Aerosol vertical mass flux measurements during heavy aerosol pollution episodes at a rural site and an urban site in the Beijing area of the North China Plain

2019 ◽  
Vol 19 (20) ◽  
pp. 12857-12874 ◽  
Author(s):  
Renmin Yuan ◽  
Xiaoye Zhang ◽  
Hao Liu ◽  
Yu Gui ◽  
Bohao Shao ◽  
...  
Keyword(s):  
Mass Flux ◽  
North China Plain ◽  
North China ◽  
Rural Site ◽  
Urban Site ◽  
The North ◽  
The North China Plain ◽  
Aerosol Pollution ◽  
The Mean ◽  
Pollution Episodes

Abstract. Due to excessive anthropogenic emissions, heavy aerosol pollution episodes (HPEs) often occur during winter in the Beijing–Tianjin–Hebei (BTH) area of the North China Plain. Extensive observational studies have been carried out to understand the causes of HPEs; however, few measurements of vertical aerosol fluxes exist, despite them being the key to understanding vertical aerosol mixing, specifically during weak turbulence stages in HPEs. In the winter of 2016 and the spring of 2017 aerosol vertical mass fluxes were measured by combining large aperture scintillometer (LAS) observations, surface PM2.5 and PM10 mass concentrations, and meteorological observations, including temperature, relative humidity (RH), and visibility, at a rural site in Gucheng (GC), Hebei Province, and an urban site at the Chinese Academy of Meteorological Sciences (CAMS) in Beijing located 100 km to the northeast. These are based on the light propagation theory and surface-layer similarity theory. The near-ground aerosol mass flux was generally lower in winter than in spring and weaker in rural GC than in urban Beijing. This finding provides direct observational evidence for a weakened turbulence intensity and low vertical aerosol fluxes in winter and polluted areas such as GC. The HPEs included a transport stage (TS), an accumulative stage (AS), and a removal stage (RS). During the HPEs from 25 to 31 January 2017, in Beijing, the mean mass flux decreased by 51 % from 0.0049 mg m−2 s−1 in RSs to 0.0024 mg m−2 s−1 in the TSs. During the ASs, the mean mass flux decreased further to 0.00087 mg m−2 s−1, accounting for approximately one-third of the flux in the TSs. A similar reduction from the TSs to ASs was observed in the HPE from 16 to 22 December 2016 in GC. It can be seen that from the TS to the AS, the aerosol vertical turbulent flux decreased, but the aerosol particle concentration within the surface layer increased, and it is inferred that in addition to the contribution of regional transport from upwind areas during the TS, suppression of vertical turbulence mixing confining aerosols to a shallow boundary layer increased accumulation.

Different roles of nitrate and sulfate in air pollution episodes in the North China Plain

2020 ◽  
Vol 224 ◽  
pp. 117325 ◽  
Author(s):  
Yinghong Wang ◽  
Guiqian Tang ◽  
Wei Zhao ◽  
Yang Yang ◽  
Lili Wang ◽  
...  
Keyword(s):  
Air Pollution ◽  
North China Plain ◽  
North China ◽  
The North ◽  
The North China Plain ◽  
Air Pollution Episodes ◽  
Pollution Episodes

scholarly journals Aerosol Vertical Mass Flux Measurements During Heavy Aerosol Pollution Episodes at a Rural Site and an Urban Site in the Beijing Area of the North China Plain

2019 ◽  
Author(s):  
Renmin Yuan ◽  
Xiaoye Zhang ◽  
Hao Liu ◽  
Yu Gui ◽  
Bohao Shao ◽  
...  
Keyword(s):  
Mass Flux ◽  
North China Plain ◽  
North China ◽  
Rural Site ◽  
Urban Site ◽  
The North ◽  
The North China Plain ◽  
Aerosol Pollution ◽  
The Mean ◽  
Pollution Episodes

Abstract. Due to excessive anthropogenic emissions, heavy aerosol pollution episodes (HPEs) often occur during winter in the Beijing-Tianjin-Hebei (BTH) area of the North China Plain. Extensive observational studies have been carried out to understand the causes of HPEs; however, few measurements of aerosol vertical fluxes exist, despite them being the key to understanding vertical aerosol mixing, specifically during weak turbulence stages in HPEs. In the winter of 2016 and the spring of 2017, based on the light propagation theory and surface-layer similarity theory, aerosol vertical mass fluxes were measured by combining large aperture scintillometer (LAS) observations, surface PM2.5 and PM10 mass concentrations, and meteorological observations, including temperature, relative humidity (RH), and visibility, at a rural site in Gucheng (GC), Hebei Province, and an urban site at the Chinese Academy of Meteorological Sciences (CAMS) in Beijing located 100 km to the northeast. The near-ground aerosol mass flux was generally lower in winter than in spring and weaker in rural GC than in urban Beijing. This finding provides direct observational evidence from the perspective of vertical aerosol fluxes for a weakened turbulence intensity in winter and in polluted areas such as GC. The HPEs included a transport stage (TS), an accumulative stage (AS), and a removal stage (RS). During the HPEs from January 25, 2017 to January 31, 2017, in Beijing, the mean mass flux decreased by 51 % from 0.0049 mg m−2 s−1 in RSs to 0.0024 mg m−2 s−1 in the TSs. During the ASs, the mean mass flux decreased further to 0.00087 mg m−2 s−1, accounting for approximately 1/3 of the flux in the TSs. A similar reduction from the TSs to ASs was observed in the HPE from December 16, 2016 to December 22, 2016 in GC. The weakened mass flux indicates that the already weak turbulence would be further weakened by aerosol pollution to a certain extent, which would further facilitate aerosol accumulation.

China: The South–North Water Transfer Project—is it justified?

Water Policy ◽  
2003 ◽  
Vol 5 (1) ◽  
pp. 1-28 ◽  
Author(s):  
Jeremy Berkoff
Keyword(s):  
Water Scarcity ◽  
Agricultural Development ◽  
North China Plain ◽  
North China ◽  
Water Transfer ◽  
The South ◽  
The North ◽  
The North China Plain ◽  
North Water ◽  
Stressed Region

The South-North Water Transfer Project (SNWTP), if fully developed, could divert 40-50 km3/yr from the Yangtse basin to the North China plain, alleviating water scarcity for 300-325M people living in what even then will be a highly water-stressed region. Construction of the next stage, diverting up to 20 km3 at a cost of about $17,000M (including $7000M in ancillary costs), is to start in 2002/3. A recent World Bank study suggests that the project is economically attractive. This conclusion has been disputed by the World Wildlife Fund (now the Worldwide Fund for Nature). This paper concludes that little confidence can be placed in either of these analyses. It therefore seeks to throw light on how the project fits within a broader regional and agricultural development setting. The project is hugely expensive, and would at the margin tend to preserve water in low value agriculture and require the resettlement of upwards of 300,000 people. On the other hand, the pace and scale of socio-economic change in China are without precedent, and adjustment problems on the North China plain are greatly exacerbated by water scarcity. Reallocation of water from irrigation to municipal and industrial uses or to the environment is socially divisive and in some instances physically impracticable. The transfer project would greatly alleviate these difficulties. It is these arguments (which are ultimately political and pragmatic), rather than those based strictly on economic or food security concerns, that make the Government's decision to proceed with the project fully understandable.

Sign in / Sign up

Export Citation Format

Share Document