Analysis on the Influence and Cause of a Heavy Pollution Process on Air Quality in Baoding during COVID-19

In this paper, the National Centers for Environmental Prediction/National Center for Atmospheric Research (NCEP/NCAR) monthly average reanalysis data from 1954 to 2017, haze days observation data from 1954 to 2017, and PM2.5 daily average mass concentration data from 2013 to 2017 are collected and collated. Firstly, the atmospheric apparent heat source on the Qinghai-Tibet Plateau is estimated based on thermodynamic equations. The correlation between the atmospheric apparent heat source (Q1) on the Qinghai-Tibet Plateau and the air quality in China, especially in the five typical regions (Beijing-Tianjin-Hebei, Fen-Wei Plain, Yangtze River Delta, Pearl River Delta, and Sichuan-Chongqing regions) is analyzed and studied. Through comprehensive diagnosis and synthesis, the differences of the three-dimensional spatial distribution of the circulation field and temperature field (planes and sections) in China and the typical regions in the strong and weak years of the apparent heat source Q1 on the Qinghai-Tibet Plateau in winter are compared, and the different distribution characteristics of the climate circulation background causing the strong and weak years of Q1 on the Qinghai-Tibet Plateau and the influence mechanism on the air quality in different regions in China are discussed. The results show that the spatial distribution of correlation between Q1 on the Qinghai-Tibet Plateau and PM2.5 in December has a northeast-southwest boundary. There is a negative correlation in the southeast region of the boundary, with heavy pollution when the cold source is strong and light pollution when the cold source is weak, while there is a positive correlation in the northwest region of the boundary, with light pollution when the cold source is strong and heavy pollution when the cold source is weak. The Q1 on Qinghai-Tibet Plateau is negatively correlated with air pollution in Beijing-Tianjin-Hebei and Fen-Wei Plain located in the northwest region of the boundary but positively correlated with air pollution in the Yangtze River Delta, Pearl River Delta, and Sichuan-Chongqing regions located in the southeast region of the boundary. In the cold source strong year, the northerly winds are stronger in the middle and high latitudes, and there is an abnormal northerly downward flow in the southeast region, thus the pollution is aggravated by the suppression of convection–diffusion in a downward flow. However, abnormal updraft in the northwest region exists, reducing pollution. In the cold source weak year, the situation is just the opposite.

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Assessment of inter-city transport of particulate matter in the Beijing-Tianjin-Hebei region

10.5194/acp-2017-933 ◽

2017 ◽

Author(s):

Xing Chang ◽

Shuxiao Wang ◽

Bin Zhao ◽

Siyi Cai ◽

Jiming Hao

Keyword(s):

Air Quality ◽

Surface Wind ◽

Air Pollution Control ◽

Regional Transport ◽

Transport Pathways ◽

Wind Speeds ◽

Monthly Average ◽

Heavy Pollution ◽

Pollution Episodes ◽

Bth Region

Abstract. The regional transport of PM2.5 plays an important role in the air quality over the Beijing-Tianjin-Hebei (BTH) region in China. However, previous studies on regional transport of PM2.5 are mainly at province level, which is insufficient for the development of an optimal joint PM2.5 control strategy. In this study, we calculate PM2.5 inflows and outflows through the administrative boundaries of three major cities in the BTH region, i.e. Beijing, Tianjin and Shijiazhuang, using the WRF (Weather Research and Forecasting model) – CMAQ (Community Multiscale Air Quality) modelling system. The monthly average inflow fluxes indicate the major directions of PM2.5 transport. For Beijing, the PM2.5 inflow fluxes from Zhangjiakou (on the northwest) and Baoding (on the southwest) constitute 57 % of the total in winter, and Langfang (on the southeast) and Baoding constitute 73 % in summer. Based on the net PM2.5 fluxes and their vertical distributions, we find there are three major transport pathways in the BTH region: the Northwest-Southeast pathway in winter (at all levels below 1000 m), the Southeast-Northwest pathway in summer (at all levels below 1000 m), and the Southwest-Northeast pathway both in winter and in summer (mainly at 400–1000 m). In winter, even if surface wind speeds are small, the transport at above 400 m could still be strong. Among the three pathways, the Southwest-Northeast happens along with PM2.5 concentrations 30 % and 55 % higher than the monthly average in winter and summer, respectively. Analysis of two heavy pollution episodes in January and July in Beijing show a much stronger (8–16 times) transport than the monthly average, emphasizing the joint air pollution control of the cities located on the transport pathways, especially during heavy pollution episodes.

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A Study on Parameterization of the Beijing Winter Heavy Haze Events Associated with Height of Pollution Mixing Layer

Advances in Meteorology ◽

10.1155/2017/8971236 ◽

2017 ◽

Vol 2017 ◽

pp. 1-11 ◽

Cited By ~ 1

Author(s):

Tao Niu ◽

Jizhi Wang ◽

Yuanqin Yang ◽

Yaqiang Wang ◽

Cheng Chen

Keyword(s):

Boundary Layer ◽

Air Quality ◽

Large Scale ◽

North China Plain ◽

North China ◽

Eastern China ◽

Mixing Layer ◽

Vertical Diffusion ◽

Raising Awareness ◽

Heavy Pollution

North China Plain, Beijing, Tianjin, and Hebei province are the major areas facing the decreasing air quality and frequent pollution events in the recent years. Identifying the effect of meteorological conditions on changes in aerosol concentration and the mechanism for forming such heavy pollution in North China Plain has become the focus of scientific research. The influence of atmospheric boundary layer characteristics on air quality has become the focus of attention and research. However, the boundary layer describes that the influences of air pollution have sometimes been duplicated and confused with each other in some of the studies. It is necessary to pay attention to some extent, raising awareness of related pollution mixing layer. The conclusions of the study include the following:(1)The lowered height of pollution mixing layer (H_PML) was favorable for the increase of the PM2.5density. The lowered height of pollution mixing layer had significant impacts on formation of severe haze.(2)A statistical analysis of large-scale heavy pollution cases in eastern China shows that the H_PML parameters have significant contributions.(3)The feedback effect of the high value of the convection inhibition (CIN), which is unfavorable to vertical diffusion of pollution, causes further reduction of H_PML, resulting in cumulative pollution again.

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The characteristics of air pollution episodes in autumn over the southern Hebei, China

World Journal of Engineering ◽

10.1260/1708-5284.12.3.221 ◽

2015 ◽

Vol 12 (3) ◽

pp. 221-236 ◽

Cited By ~ 4

Author(s):

Fenfen Zhang ◽

Litao Wang ◽

Jing Yang ◽

Mingzhang Chen ◽

Zhe Wei ◽

...

Keyword(s):

Air Pollution ◽

Air Quality ◽

Grid Resolution ◽

Air Quality Model ◽

Fine Grid ◽

Local Emission ◽

Heavy Pollution ◽

Handan City ◽

Air Pollution Episodes ◽

Pollution Episodes

In this study, the Models-3/Community Multiscale Air Quality Model (CMAQ) coupled with the Mesoscale Modeling System Generation 5 (MM5) was employed to simulate the air pollution episodes over East Asia, northern China Plain (NCP), and southern Hebei (SHB), at a grid resolution of 36, 12, and 4 km, respectively in Oct. 2012. The PM10 concentrations over SHB at 12-km are overpredicted with NMBs of 34.6% to 45.7% and also overestimated with that of 72.1% to 97.5% at 4-km which applied such a fine grid resolution over the SHB for the first time. It indicated that the simulation at 12-km performs better than the 4-km which may be related to the spatial allocation of the emissions, the lack of dust emissions and the limitations of model treatments. Five heavy episodes show the characteristics of sawtooth-shaped cycles over the NCP in fall (i.e. the maximum of PM10 was up to 885.1 µg m−3 and PM2.5 was up to 438.4 µg m−3 in Handan city) which resulting in the deterioration of visibility and periodically haze days. The concentrations of OC, EC, SO42−, NO3− and NH4+ were significantly higher in heavy episodes than non-heavy pollution episodes. In comparison with other cities ([NO3−]/[SO42−] > 1) at 12-km, the monthly-mean mass ratio of [NO3−]/[SO42−] at Taiyuan (0.17−0.73), Shijiazhuang (0.28−2.34) was 0.43, 0.84 respectively, which means the stationary sources emissions were more important than the vehicle emission in the source areas. The influence of the regional transportation for pollutants compared with local emission was also an important factor for heavy pollution episodes. The regional joint framework should be established along with controlling the local emission over the SHB in China to improve the air quality.

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Application of Electron Optics to Characterization of Particulate Pollutants

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s042482010009508x ◽

1972 ◽

Vol 30 ◽

pp. 364-365

Author(s):

J. B. Moran ◽

J. L. Miller

Keyword(s):

Air Quality ◽

Quality Standards ◽

Ambient Air ◽

Hazardous Substances ◽

Fuel Additives ◽

Ambient Air Quality ◽

Air Quality Standards ◽

Emission Standards ◽

Stationary Sources ◽

Ambient Air Quality Standards

The Clean Air Act Amendments of 1970 provide the basis for a dramatic change in Federal air quality programs. The Act establishes new standards for motor vehicles and requires EPA to establish national ambient air quality standards, standards of performance for new stationary sources of pollution, and standards for stationary sources emitting hazardous substances. Further, it establishes procedures which allow states to set emission standards for existing sources in order to achieve national ambient air quality standards. The Act also permits the Administrator of EPA to register fuels and fuel additives and to regulate the use of motor vehicle fuels or fuel additives which pose a hazard to public health or welfare.National air quality standards for particulate matter have been established. Asbestos, mercury, and beryllium have been designated as hazardous air pollutants for which Federal emission standards have been proposed.

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