Analysis of a winter regional haze event and its formation mechanism in the North China Plain

Abstract. A regional haze episode occurred in the Beijing, Tianjin and Hebei province (BTH) area in the North China Plain (NCP) from 16 to 19 January 2010. The chemical and optical properties of aerosols and the meteorological condition were investigated in this study with intensive measurement of aerosol and trace gases from 14 to 23 January 2010 at five sites. The episode was caused by the combination of anthropogenic emissions and surface air stagnation under a high pressure system followed by a low pressure system. The concentrations of PM2.5 and trace gases increased significantly on a regional scale during this episode. The increased aerosol scattering coefficient (σsp), absorption coefficient (σap), and aerosol optical depth (AOD) showed the importance of aerosol extinction during this haze episode. The increase of secondary inorganic pollutants (SO42−, NO3−, NH4+) was observed simultaneously at four sites, especially in the plain area of BTH, which could be identified as a common characteristic of pollution haze in east China. The organic matter (OM) was different from secondary inorganic pollutants, which increased more significantly at Chengde (CD) site than the other three sites in plain area. The sulfate and nitrate in PM2.5 were mainly formed through the heterogeneous reaction process in the urban area. The secondary organic aerosols in PM2.5 only existed during haze days at CD but in both haze and normal days at the other three sites. The chemical characteristics of aerosols in PM2.5 indicated that the secondary formation of aerosol was one important mechanism in the formation of haze episode. The strong temperature inversion and descending air motions in the planetary boundary layer (PBL) allowed pollutants to accumulate in a shallow layer. The weak surface wind speed produced high pollutants concentration within these source regions. The accumulation of pollutants was one main factor in the haze formation. The enhanced southwest wind in the last period of this episode transported pollutants to the downwind area and expanded the regional scope of the haze.

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Analysis of a winter regional haze event and its formation mechanism in the North China Plain

Atmospheric Chemistry and Physics ◽

10.5194/acp-13-5685-2013 ◽

2013 ◽

Vol 13 (11) ◽

pp. 5685-5696 ◽

Cited By ~ 413

Author(s):

X. J. Zhao ◽

P. S. Zhao ◽

J. Xu ◽

W. Meng, ◽

W. W. Pu ◽

...

Keyword(s):

North China Plain ◽

North China ◽

The Other ◽

Plain Area ◽

The North ◽

The North China Plain ◽

Secondary Formation ◽

Regional Haze ◽

Haze Episode ◽

Haze Days

Abstract. A regional haze episode occurred in the Beijing, Tianjin and Hebei province (BTH) area in the North China Plain (NCP) from 16 to 19 January 2010. Data were collected and analyzed during the time frame of 14 through 23 January 2010 to include the haze event. The increase of secondary inorganic pollutants (SO42−, NO3−, NH4+) in PM2.5 was observed simultaneously at four sites, especially in the plain area of the BTH, which could be identified as a common characteristic of pollution haze in east China. The sulfate and nitrate in PM2.5 were mainly formed through the heterogeneous reaction process in the urban area. The organic matter (OM) increased more significantly at the Chengde (CD) site than the other three sites in the plain area. The secondary organic aerosols only existed during haze days at CD but in both haze and non-haze days at the other three sites, which suggested the greater regional impact of secondary formation process during the haze episode. The secondary formation of aerosol was one important formation mechanism of haze. The strong temperature inversion and descending air motions in the planetary boundary layer (PBL) allowed pollutants to accumulate in a shallow layer. The weak surface wind speed produced high pollutants concentration within source regions. The accumulation of pollutants was one main factor in the haze formation. The enhanced southwest wind in the last period of this episode transported pollutants to the downwind area and expanded the regional scope of the haze.

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Comprehensive study of regional haze in the North China Plain with synergistic measurement from multiple mobile vehicle-based lidars and a lidar network

The Science of The Total Environment ◽

10.1016/j.scitotenv.2020.137773 ◽

2020 ◽

Vol 721 ◽

pp. 137773 ◽

Cited By ~ 1

Author(s):

Lihui Lv ◽

Yan Xiang ◽

Tianshu Zhang ◽

Wenxuan Chai ◽

Wenqing Liu

Keyword(s):

North China Plain ◽

North China ◽

The North ◽

Mobile Vehicle ◽

The North China Plain ◽

Regional Haze ◽

Comprehensive Study

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Characteristics and formation mechanism of continuous hazes in China: a case study during the autumn of 2014 in the North China Plain

Atmospheric Chemistry and Physics ◽

10.5194/acp-15-8165-2015 ◽

2015 ◽

Vol 15 (14) ◽

pp. 8165-8178 ◽

Cited By ~ 109

Author(s):

Y. R. Yang ◽

X. G. Liu ◽

Y. Qu ◽

J. L. An ◽

R. Jiang ◽

...

Keyword(s):

Formation Mechanism ◽

North China Plain ◽

North China ◽

Surface Wind ◽

Motor Vehicles ◽

Chemical Compositions ◽

Beijing City ◽

The North ◽

The North China Plain ◽

Haze Episode

Abstract. Four extreme haze episodes occurred in October 2014 in the North China Plain (NCP). To clarify the formation mechanism of hazes in autumn, strengthened observations were conducted in Beijing from 5 October to 2 November. The meteorological parameters, satellite data, chemical compositions and optical properties of aerosols were obtained. The hazes originated from the NCP, developing in the southwest and northeast directions, with the highest concentration of PM2.5 of 469 μg m−3 in Beijing. The NCP was dominated by a weak high pressure system during the haze episode, which resulted in low surface wind speed and relatively stagnant weather. Moreover, the wind slowed down around Beijing city. The secondary aerosols NO3− was always higher than that of SO42−, which indicated the motor vehicles played a more important part in the hazes in October 2014, even though the oxidation rate from SO2 to SO42− was faster than that of NOx to NO3−. Sudden increases of the concentrations of organic matter, Cl− and BC (black carbon) before each haze episode implied that regional transport of pollutants by biomass burning was important for haze formation during autumn. A satellite map of fire points and the backward trajectories of the air masses also indicated this pollution source. The distinct decrease in the PBL (planetary boundary layer) height during four haze episodes restrained the vertical dispersion of the air pollutants. Water vapor also played a vital role in the formation of hazes by accelerating the chemical transformation of secondary pollutants, leading to hygroscopic growth of aerosols and altering the thermal balance of the atmosphere.

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Modeling study of the 2010 regional haze event in the North China Plain

Atmospheric Chemistry and Physics Discussions ◽

10.5194/acpd-15-22781-2015 ◽

2015 ◽

Vol 15 (16) ◽

pp. 22781-22822 ◽

Cited By ~ 8

Author(s):

M. Gao ◽

G. R. Carmichael ◽

Y. Wang ◽

P. E. Saide ◽

M. Yu ◽

...

Keyword(s):

Air Pollutants ◽

North China Plain ◽

North China ◽

Weather Conditions ◽

Air Pollution Control ◽

Wind Speeds ◽

The North ◽

The North China Plain ◽

Haze Event ◽

Regional Haze

Abstract. The online coupled Weather Research and Forecasting-Chemistry (WRF-Chem) model was applied to simulate a haze event that happened in January 2010 in the North China Plain (NCP), and was validated against various types of measurements. The evaluations indicate that WRF-Chem provides reliable simulations for the 2010 haze event in the NCP. This haze event is mainly caused by high emissions of air pollutants in the NCP and stable weather conditions in winter. Secondary inorganic aerosols also played an important role and cloud chemistry had important contributions. Air pollutants outside Beijing contributed about 47.8 % to the PM2.5 levels in Beijing during this haze event, and most of them are from south Hebei, Shandong and Henan provinces. In addition, aerosol feedback has important impacts on surface temperature, Relative Humidity (RH) and wind speeds, and these meteorological variables affect aerosol distribution and formation in turn. In Shijiazhuang, Planetary Boundary Layer (PBL) decreased about 300 m and PM2.5 increased more than 20 μg m-3 due to aerosol feedback. Feedbacks associated to Black Carbon (BC) account for about 50 % of the PM2.5 increases and 50 % of the PBL decreases in Shijiazhuang, indicating more attention should be paid to BC from both air pollution control and climate change perspectives.

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Wintertime aerosol chemistry and haze evolution in an extremely polluted city of the North China Plain: significant contribution from coal and biomass combustion

Atmospheric Chemistry and Physics ◽

10.5194/acp-17-4751-2017 ◽

2017 ◽

Vol 17 (7) ◽

pp. 4751-4768 ◽

Cited By ~ 75

Author(s):

Haiyan Li ◽

Qi Zhang ◽

Qiang Zhang ◽

Chunrong Chen ◽

Litao Wang ◽

...

Keyword(s):

Air Pollution ◽

Biomass Burning ◽

Coal Combustion ◽

North China Plain ◽

North China ◽

Biomass Combustion ◽

The North ◽

The North China Plain ◽

Haze Pollution ◽

Haze Episode

Abstract. The North China Plain (NCP) frequently experiences heavy haze pollution, particularly during wintertime. In winter 2015–2016, the NCP region suffered several extremely severe haze episodes with air pollution red alerts issued in many cities. We have investigated the sources and aerosol evolution processes of the severe pollution episodes in Handan, a typical industrialized city in the NCP region, using real-time measurements from an intensive field campaign during the winter of 2015–2016. The average (±1σ) concentration of submicron aerosol (PM1) during 3 December 2015–5 February 2016 was 187.6 (±137.5) µg m−3, with the hourly maximum reaching 700.8 µg m−3. Organic was the most abundant component, on average accounting for 45 % of total PM1 mass, followed by sulfate (15 %), nitrate (14 %), ammonium (12 %), chloride (9 %) and black carbon (BC, 5 %). Positive matrix factorization (PMF) with the multilinear engine (ME-2) algorithm identified four major organic aerosol (OA) sources, including traffic emissions represented by a hydrocarbon-like OA (HOA, 7 % of total OA), industrial and residential burning of coal represented by a coal combustion OA (CCOA, 29 % of total OA), open and domestic combustion of wood and crop residuals represented by a biomass burning OA (BBOA, 25 % of total OA), and formation of secondary OA (SOA) in the atmosphere represented by an oxygenated OA (OOA, 39 % of total OA). Emissions of primary OA (POA), which together accounted for 61 % of total OA and 27 % of PM1, are a major cause of air pollution during the winter. Our analysis further uncovered that primary emissions from coal combustion and biomass burning together with secondary formation of sulfate (mainly from SO2 emitted by coal combustion) are important driving factors for haze evolution. However, the bulk composition of PM1 showed comparatively small variations between less polluted periods (daily PM2. 5 ≤  75 µg m−3) and severely polluted periods (daily PM2. 5 >  75 µg m−3), indicating relatively synchronous increases of all aerosol species during haze formation. The case study of a severe haze episode, which lasted 8 days starting with a steady buildup of aerosol pollution followed by a persistently high level of PM1 (326.7–700.8 µg m−3), revealed the significant influence of stagnant meteorological conditions which acerbate air pollution in the Handan region. The haze episode ended with a shift of wind which brought in cleaner air masses from the northwest of Handan and gradually reduced PM1 concentration to <  50 µg m−3 after 12 h. Aqueous-phase reactions under higher relative humidity (RH) were found to significantly promote the production of secondary inorganic species (especially sulfate) but showed little influence on SOA.

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Impact of Expansion Pattern of Built-Up Land in Floodplains on Flood Vulnerability: A Case Study in the North China Plain Area

Remote Sensing ◽

10.3390/rs12193172 ◽

2020 ◽

Vol 12 (19) ◽

pp. 3172

Author(s):

Guangpeng Wang ◽

Ziying Hu ◽

Yong Liu ◽

Guoming Zhang ◽

Jifu Liu ◽

...

Keyword(s):

Flood Risk ◽

North China Plain ◽

North China ◽

Flood Vulnerability ◽

Plain Area ◽

The North ◽

The North China Plain ◽

Flood Exposure ◽

Expansion Pattern ◽

The Relationship

Built-up land in floodplains (BLF) is a driver and a disaster-bearing body of flood risk from a socio-hydrological perspective. The relationship between BLF growth and flood vulnerability is the key to understanding and managing flood risk. However, previous studies have focused more on the relationship between BLF growth and flood exposure, ignoring flood vulnerability. We examined the BLF expansion pattern (patch size and expansion type) in the North China Plain Area from 1975 to 2014 (1975–1990–2000–2014) using GIS (geographic information system)-based landscape analysis and revealed its relationship with flood vulnerability. The results show that the BLF area experienced rapid growth (288.26%) from dispersion to coalescence. Small patches dominated the number and area of BLF growth, and edge-expansion patches were the expansion type with the most area growth. We discovered that flood vulnerability was significantly correlated with the growth in small (R = 0.36, p < 0.01), edge-expansion (R = 0.53, p < 0.01), and outlying patches (R = 0.51, p < 0.01). Large patches were not significantly correlated with flood vulnerability (R = 0.18, p > 0.1), but there was a negative trend. Infilling patch growth was significantly associated with flood vulnerability over a long period (R = 0.27, p < 0.05). In addition, we suggest nature-based soft adaptations or village merging for small patches and outlying patches. Our findings have important scientific significance for adequately understanding the interplay between BLF growth and flood risk. It has practical implications for the formulation of integrated flood risk management strategy and the sustainable development of floodplains.

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Optical and radiative properties of aerosols during a severe haze episode over the North China Plain in December 2016

Journal of Meteorological Research ◽

10.1007/s13351-017-7073-7 ◽

2017 ◽

Vol 31 (6) ◽

pp. 1045-1061 ◽

Cited By ~ 5

Author(s):

Yu Zheng ◽

Huizheng Che ◽

Leiku Yang ◽

Jing Chen ◽

Yaqiang Wang ◽

...

Keyword(s):

North China Plain ◽

North China ◽

Radiative Properties ◽

The North ◽

The North China Plain ◽

Haze Episode

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Characteristics and formation mechanism of continuous extreme hazes in China: a case study in autumn of 2014 in the North China Plain

Atmospheric Chemistry and Physics Discussions ◽

10.5194/acpd-15-10987-2015 ◽

2015 ◽

Vol 15 (7) ◽

pp. 10987-11029 ◽

Cited By ~ 21

Author(s):

Y. R. Yang ◽

X. G. Liu ◽

Y. Qu ◽

J. L. An ◽

R. Jiang ◽

...

Keyword(s):

Formation Mechanism ◽

North China Plain ◽

North China ◽

Surface Wind ◽

Motor Vehicles ◽

Chemical Compositions ◽

Beijing City ◽

The North ◽

The North China Plain ◽

Haze Episode

Abstract. Four extreme haze episodes occurred in October 2014 in the North China Plain (NCP). To clarify the formation mechanism of hazes in the autumn, strengthened observations were conducted in Beijing from 5 October to 2 November. The meteorological parameters, satellite data, chemical compositions and optical properties of aerosols were obtained. The hazes originated from NCP, developing in the southwest and northeast directions, with the highest concentration of PM2.5 of 469 μg m−3 in Beijing. NCP was dominated by a weak high pressure system during the haze episode, which resulted in low surface wind speed and relatively stagnant weather. Moreover, the wind slowed down around Beijing city. The secondary aerosols NO3− was always higher than that of SO42−, which indicated the motor vehicles played a more important part in the hazes in October 2014, even though the oxidation rate from SO2 to SO42− was faster than that of NOx to NO3−. Sudden increases of the concentrations of organic matter, Cl− and BC (Black carbon) before each haze episode implied that regional transport of pollutants by biomass burning was important for haze formation during the autumn. A satellite map of fire points and the backward trajectories of the air masses also indicated this pollution source. The distinct decrease in the PBL (planetary boundary layer) height during four haze episodes restrained the vertical dispersion of the air pollutants. Water vapor also played a vital role in the formation of hazes by accelerating the chemical transformation of secondary pollutants, leading to hygroscopic growth of aerosols and altering the thermal balance of the atmosphere.

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Characteristics of trace gaseous pollutants at a regional background station in Northern China

Atmospheric Chemistry and Physics ◽

10.5194/acp-9-927-2009 ◽

2009 ◽

Vol 9 (3) ◽

pp. 927-936 ◽

Cited By ~ 69

Author(s):

Z. Y. Meng ◽

X. B. Xu ◽

P. Yan ◽

G. A. Ding ◽

J. Tang ◽

...

Keyword(s):

North China Plain ◽

North China ◽

Trace Gases ◽

Northern China ◽

Diurnal Variations ◽

Gaseous Pollutants ◽

The North ◽

The North China Plain ◽

Plain Region ◽

Co Concentrations

Abstract. Measurements of trace gaseous pollutants were taken at the Shangdianzi site, a WMO Global Atmosphere Watch (GAW) background station in Northern China. The results are presented for the period from September 2003 to December 2006. Seasonal and diurnal variations of the O3, NOx, SO2, and CO concentration are characterized and possible causes for them are discussed. The observed levels of the trace gases are comparable to those at some other background sites in polluted regions inside and outside of China. It was shown that the seasonal variation of O3 can change slightly from year to year due to the year-to-year alternation in the meteorological conditions. Higher CO concentrations were observed in some warmer months, particularly in June and July, 2006. Intensive biomass burning in the North China Plain region, in combination with the transport of regional pollution by more frequent southwesterly winds, is believed to be responsible for the elevated CO concentrations. The diurnal variation of O3, with delayed peaking times, suggests that the transport of photochemical aged plume is an important source for O3 at Shangdianzi. The diurnal variations of SO2 in all seasons show higher values during daytime, contradicting the common view. An explanation for this unusual phenomenon is hypothesized. To gain an insight into the impact of transport on the trace gases levels at Shangdianzi, air mass backward trajectories were calculated and analyzed in combination with corresponding pollutant concentrations. The results indicate that the transport of air masses from the North China Plain region and from the major coal mining regions west of Shangdianzi is responsible for the high concentrations of the gaseous pollutants.

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