scholarly journals Observation of regional air pollutant transport between the megacity Beijing and the North China Plain

2016 ◽  
Author(s):  
Yingruo Li ◽  
Chunxiang Ye ◽  
Jun Liu ◽  
Yi Zhu ◽  
Junxia Wang ◽  
...  
Keyword(s):  
Air Quality ◽  
Air Pollutants ◽  
North China Plain ◽  
North China ◽  
Pollutant Transport ◽  
Air Pollutant ◽  
The North ◽  
The North China Plain ◽  
Transport Flux

Abstract. Megacities have strong interactions with the surrounding regions through transport of air pollutants. It has been frequently addressed that the air quality of Beijing was influenced by the influx of air pollutants from the North China Plain (NCP). However, estimations of air pollutant transport between megacities and surrounding regions using long–term observations are very limited. Using the observational results of the gaseous pollutants SO2, NO, NO2, O3, and CO from August 2006 to October 2008 at the Yufa site, a rural site south of Beijing, together with meteorological parameters, we evaluated the transport flux between Beijing and the NCP, as part of the “Campaign of Air Quality Research in Beijing and Surrounding Region 2006–2008” (CAREBeijing 2006–2008). The bivariate polar plots showed the dependence of pollutant concentrations on both wind speed and wind direction, and thus inferred their dominant transport directions. Surface flux calculations further demonstrated the transport directions and the seasonal variations in the cumulative transport strengths. The cumulative transport strengths of SO2, NO, NO2, NOx (NOx = NO +  NO2), O3, Ox (Ox = O3 + NO2), and CO were 92.6, –62.2, –8.9, –71.0, 217.3, 213.8, and 1038.1 mg s−1 m−2 during the observation period, respectively. For SO2, CO, and O3, the transport fluxes were from the NCP to Beijing in all seasons except winter, with the strongest fluxes largely in summer. The transport flux of NOx was from Beijing to the NCP except in summer, with the strongest flux in winter. Finally, our analysis suggests a profound influence of regional transport between Beijing and the NCP on the air quality of the megacity Beijing. Our study also suggested that various factors, such as the wind field, emission inventory, and photochemical reactions, could influence the transport of air pollutants between Beijing and the NCP. Therefore, both local emission reduction and regional cooperation must be considered in air quality management of the megacity Beijing.

scholarly journals Observation of regional air pollutant transport between the megacity Beijing and the North China Plain

2016 ◽  
Vol 16 (22) ◽  
pp. 14265-14283 ◽  
Author(s):  
Yingruo Li ◽  
Chunxiang Ye ◽  
Jun Liu ◽  
Yi Zhu ◽  
Junxia Wang ◽  
...  
Keyword(s):  
Air Quality ◽  
Air Pollutants ◽  
North China Plain ◽  
Surface Flux ◽  
Air Pollutant ◽  
Surface Transport ◽  
The North ◽  
Flux Intensity ◽  
Transport Flux ◽  
Observation Period

Abstract. Megacities have strong interactions with the surrounding regions through transport of air pollutants. It has been frequently addressed that the air quality of Beijing is influenced by the influx of air pollutants from the North China Plain (NCP). Estimations of air pollutant cross-boundary transport between Beijing and the NCP are important for air quality management. However, evaluation of cross-boundary transport using long-term observations is very limited. Using the observational results of the gaseous pollutants SO2, NO, NO2, O3, and CO from August 2006 to October 2008 at the Yufa site, a cross-boundary site between the megacity Beijing and the NCP, together with meteorological parameters, we explored a method for evaluating the transport flux intensities at Yufa, as part of the “Campaign of Air Quality Research in Beijing and Surrounding Region 2006–2008” (CAREBeijing 2006–2008). The hourly mean ± SD (median) concentration of SO2, NO, NO2, NOx, O3, Ox, and CO was 15 ± 16 (9) ppb, 12 ± 25 (3) ppb, 24 ± 19 (20) ppb, 36 ± 39 (23) ppb, 28 ± 27 (21) ppb, 52 ± 24 (45) ppb, and 1.6 ± 1.4 (1.2) ppm during the observation period, respectively. The bivariate polar plots showed the dependence of pollutant concentrations on both wind speed and wind direction, and thus inferred their dominant transport directions. Surface flux intensity calculations further demonstrated the regional transport influence of Beijing and the NCP on Yufa. The net surface transport flux intensity (mean ± SD) of SO2, NO, NO2, NOx, O3, Ox, and CO was 6.2 ± 89.5, −4.3 ± 29.5, −0.6 ± 72.3, −4.9 ± 93.0, 14.7 ± 187.8, 14.8 ± 234.9, and 70 ± 2830 µg s−1 m−2 during the observation period, respectively. For SO2, CO, O3, and Ox the surface flux intensities from the NCP to Yufa surpassed those from Beijing to Yufa in all seasons except winter, with the strongest net fluxes largely in summer, which were about 4–8 times those of other seasons. The surface transport flux intensity of NOx from Beijing to Yufa was stronger than that from the NCP to Yufa except in summer, with the strongest net flux in winter, which was about 1.3–8 times that of other seasons. The flux intensities were then assigned to the corresponding trajectories in the potential source contribution function analysis (PSCF), which confirmed the results of flux intensity calculations. Our study also suggested that various factors, such as the wind field, emission inventory, and photochemical reactions, could influence transport of air pollutants. The decrease of surface flux intensity during the Olympic Games implied the role of both local emission reduction and regional cooperation in successful air quality management. Three dimensional observations are needed for further comprehensive discussion of the regional transport between Beijing and the NCP.

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 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.

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.

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 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.

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