scholarly journals Characteristics of pollutants and their correlation to meteorological conditions at a suburban site in the North China Plain

2011 ◽  
Vol 11 (9) ◽  
pp. 4353-4369 ◽  
Author(s):  
W. Y. Xu ◽  
C. S. Zhao ◽  
L. Ran ◽  
Z. Z. Deng ◽  
P. F. Liu ◽  
...  
Keyword(s):  
North China Plain ◽  
North China ◽  
Meteorological Data ◽  
Trace Gases ◽  
Strong Dependence ◽  
Air Pollutant ◽  
Trace Gas ◽  
Pollution Levels ◽  
The North ◽  
Pollutant Concentrations

Abstract. North China Plain (NCP) is one of the most densely populated regions in China and has experienced enormous economic growth in the past decades. Its regional trace gas pollution has also become one of the top environmental concerns in China. Measurements of surface trace gases, including O3, NOx, SO2 and CO were carried out within the HaChi (Haze in China) project at Wuqing Meteorology Station, located between 2 mega-cities (Beijing and Tianjin) in the NCP, from 9 July 2009 to 21 January 2010. Detailed statistical analyses were made in order to provide information on the levels of the measured air pollutants and their characteristics. Gaseous air pollutant concentrations were also studied together with meteorological data and satellite data to help us better understand the causes of the observed variations in the trace gases during the field campaign. In comparison to measurements from other rural and background stations in the NCP, relatively high concentrations were detected in Wuqing, presumably due to regional mixing and transport of pollutants. Local meteorology had deterministic impacts on air pollution levels, which have to be accounted for when evaluating other effects on pollutant concentrations. Trace gas concentrations showed strong dependence on wind, providing information on regional pollution characteristics. O3 mixing ratio also showed clear dependencies on temperature and relative humidity.

scholarly journals Characteristics of pollutants and their correlation to meteorological conditions at a suburban site in the North China Plain

2011 ◽  
Vol 11 (3) ◽  
pp. 7113-7154 ◽  
Author(s):  
W. Y. Xu ◽  
C. S. Zhao ◽  
L. Ran ◽  
Z. Z. Deng ◽  
P. F. Liu ◽  
...  
Keyword(s):  
North China Plain ◽  
North China ◽  
Meteorological Data ◽  
Trace Gases ◽  
Strong Dependence ◽  
Air Pollutant ◽  
Trace Gas ◽  
Pollution Levels ◽  
The North ◽  
Pollutant Concentrations

Abstract. North China Plain (NCP) is one of the most densely populated regions in China and has experienced enormous economic growth in the past decades. Its regional trace gas pollution has also become one of the top environmental concerns in China. Measurements of surface trace gases, including O3, NOx, SO2 and CO were carried out within the HaChi (Haze in China) project at Wuqing Meteorology Station, located between 2 mega-cities (Beijing and Tianjin) in the NCP, from 9 July 2009 to 21 January 2010. Detailed statistical analyses were made in order to provide information on the levels of the measured air pollutants and their characteristics. Gaseous air pollutant concentrations were also studied together with meteorological data and satellite data to help us better understand the causes of the observed variations in the trace gases during the field campaign. In comparison to measurements from other rural and background stations in the NCP, relatively higher concentrations were detected in Wuqing, presumably due to regional mixing and transport of pollutants. Local meteorology had deterministic impacts on air pollution levels, which have to be accounted for when evaluating other effects on pollutant concentrations. Trace gas concentrations showed strong dependence on wind, providing information on regional pollution characteristics. O3 mixing ratio also showed clear dependencies on temperature and relative humidity.

scholarly journals Cloud scavenging of abundant anthropogenic refractory particles at a mountain site in North China

2018 ◽  
Author(s):  
Lei Liu ◽  
Jian Zhang ◽  
Liang Xu ◽  
Qi Yuan ◽  
Dao Huang ◽  
...  
Keyword(s):  
North China Plain ◽  
North China ◽  
Size Composition ◽  
Climate Forcing ◽  
Pollution Levels ◽  
Aerosol Cloud ◽  
The North ◽  
The North China Plain ◽  
Transmission Electron ◽  
Cloud Scavenging

Abstract. Aerosol-cloud interaction remains a major source of uncertainty in climate forcing estimate. Our knowledge about the aerosol-cloud interaction is particularly weak in heavily polluted conditions. In this study, cloud residual (cloud RES) and cloud interstitial (cloud INT) particles were collected during cloud events under different pollution levels from 22 July to 1 August, 2014 at Mt. Tai (1532 m above sea level) located in the North China Plain (NCP). Transmission electron microscopy (TEM) was used to investigate size, composition, and mixing state of individual cloud RES and INT particles. Our results show that S-rich particles were predominant (78 %) during clean periods (PM2.5 

scholarly journals Spatial Characteristics of PM2.5 Pollution among Cities and Policy Implication in the Northern Part of the North China Plain

Atmosphere ◽  
2021 ◽  
Vol 12 (1) ◽  
pp. 77
Author(s):  
Yangjun Wang ◽  
Hongli Li ◽  
Jin Feng ◽  
Wu Wang ◽  
Ziyi Liu ◽  
...  
Keyword(s):  
Prevention And Control ◽  
North China Plain ◽  
North China ◽  
Recent Decade ◽  
Clustering Coefficient ◽  
Spatial Characteristics ◽  
Pollution Levels ◽  
The North ◽  
The North China Plain ◽  
And Control

In the recent decade, the North China Plain (NCP) has been among the region’s most heavily polluted by PM2.5 in China. For the nonattainment cities in the NCP, joint pollution control with related cities is highly needed in addition to the emission controls in their own cities. However, as the basis of decision-making, the spatial characteristics of PM2.5 among these cities are still insufficiently revealed. In this work, the spatial characteristics among all nonattainment cities in the northern part of the North China Plain (NNCP) region were revealed based on data mining technologies including clustering, coefficient of divergence (COD), network correlation model, and terrain and meteorology analysis. The results indicate that PM2.5 pollution of cities with a distance of less than 180 km exhibits homogeneity in the NCP region. Especially, the sub-region, composed of Xinxiang, Hebi, Kaifeng, Zhengzhou, and Jiaozuo, was strongly homogeneous and a strong correlation exists among them. Compared with spring and summer, much stronger correlations of PM2.5 between cities were found in autumn and winter, indicating a strong need for joint prevention and control during these periods. All nonattainment cities in this region were divided into city-clusters, depending on the seasons and pollution levels to further helping to reduce their PM2.5 concentrations effectively. Air stagnation index (ASI) analysis indicates that the strong correlations between cities in autumn were more attributed to the transport impacts than those in winter, even though there were higher PM2.5 concentrations in winter. These results provided an insight into joint prevention and control of pollution in the NCP region.

scholarly journals Amplified role of potential HONO sources in O<sub>3</sub> formation in North China Plain during autumn haze aggravating processes

2021 ◽  
Author(s):  
Jingwei Zhang ◽  
Chaofan Lian ◽  
Weigang Wang ◽  
Maofa Ge ◽  
Yitian Guo ◽  
...  
Keyword(s):  
North China Plain ◽  
North China ◽  
Heterogeneous Reaction ◽  
Ground Surface ◽  
Field Studies ◽  
Daily Maximum ◽  
Pollution Levels ◽  
The North ◽  
Order Of Magnitude ◽  
High Concentrations

Abstract. Co-occurrences of high concentrations of PM2.5 and ozone (O3) have been frequently observed in haze aggravating processes in the North China Plain (NCP) over the past few years, and higher O3 concentrations during hazy days were supposed to be related to nitrous acid (HONO), but the key sources of HONO enhancing O3 during haze aggravating processes remain unclear, and will be explored in this study by using the WRF-Chem model, which is improved to include ground-based (traffic, soil, and indoor emissions, and the NO2 heterogeneous reaction on ground surface (Hetground)) and aerosol-related (the NO2 heterogeneous reaction on aerosol surfaces (Hetaerosol) and nitrate photolysis (Photnitrate)) potential HONO sources. The results indicate that ground-based HONO sources producing HONO enhancements showed a rapid decrease with height, while the NO+OH reaction and aerosol-related HONO sources decreased slowly with height. Photnitrate contributions to HONO concentrations enhanced with aggravated pollution levels, the enhanced HONO due to Photnitrate in hazy days was about one order of magnitude larger than in clean days and Photnitrate dominated HONO sources (~30–70 % when the ratio of the photolysis frequency of nitrate (Jnitrate) to gas nitric acid (JHNO3) equals 30) at higher layers (> 800 m). Compared with that in clean days, the Photnitrate contribution to the enhanced daily maximum 8-h averaged O3 was increased by over one magnitude during the haze aggravating process. Photnitrate contributed only ~5 % of the surface HONO in daytime with a Jnitrate/JHNO3 ratio of 30 but contributed ~30–50 % of the enhanced O3 near the surface in NCP in hazy days. Surface O3 was dominated by volatile organic compounds-sensitive chemistry, while O3 at higher altitude (> 800 m) was dominated by NOx-sensitive chemistry. Photnitrate had a limited impact on nitrate concentrations (< 15 %) even with a Jnitrate/JHNO3 ratio of 120. The above results suggest that more field studies of Jnitrate in the atmosphere are still needed.

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

2009 ◽  
Vol 9 (3) ◽  
pp. 927-936 ◽  
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.

scholarly journals Vertical profiles of NO<sub>2</sub>, SO<sub>2</sub>, HONO, HCHO, CHOCHO and aerosols derived from MAX-DOAS measurements at a rural site in the central western North China Plain and their relation to emission sources and effects of regional transport

2019 ◽  
Vol 19 (8) ◽  
pp. 5417-5449 ◽  
Author(s):  
Yang Wang ◽  
Steffen Dörner ◽  
Sebastian Donner ◽  
Sebastian Böhnke ◽  
Isabelle De Smedt ◽  
...  
Keyword(s):  
Boundary Layer ◽  
North China Plain ◽  
North China ◽  
Trace Gases ◽  
Vertical Profiles ◽  
Regional Transport ◽  
Near Surface ◽  
The North ◽  
Backward Propagation

Abstract. A multi-axis differential optical absorption spectroscopy (MAX-DOAS) instrument was deployed in May and June 2016 at a monitoring station (37.18∘ N, 114.36∘ E) in the suburban area of Xingtai, which is one of the most polluted cities in the North China Plain (NCP), during the Atmosphere-Aerosol-Boundary Layer-Cloud (A2BC) experiment and Air chemistry Research In Asia (ARIAs) joint experiments to derive tropospheric vertical profiles of NO2, SO2, HONO, HCHO, CHOCHO and aerosols. Aerosol optical depths derived from MAX-DOAS were found to be consistent with collocated sun-photometer measurements. Also the derived near-surface aerosol extinction and HCHO mixing ratio agree well with the coincident visibility meter and in situ HCHO measurements, with mean HCHO near-surface mixing ratios of ∼3.5 ppb. Underestimations of MAX-DOAS results compared to in situ measurements of NO2 (∼60 %) and SO2 (∼20 %) are found expectedly due to vertical and horizontal inhomogeneity of trace gases. Vertical profiles of aerosols and NO2 and SO2 are reasonably consistent with those measured by a collocated Raman lidar and aircraft spirals over the station. The deviations can be attributed to differences in sensitivity as a function of altitude and substantial horizontal gradients of pollutants. Aerosols, HCHO and CHOCHO profiles typically extended to higher altitudes (with 75 % integrated column located below ∼1.4 km) than NO2, SO2 and HONO did (with 75 % integrated column below ∼0.5 km) under polluted conditions. Lifted layers were systematically observed for all species (except HONO), indicating accumulation, secondary formation or long-range transport of the pollutants at higher altitudes. Maximum values routinely occurred in the morning for NO2, SO2 and HONO but occurred at around noon for aerosols, HCHO and CHOCHO, mainly dominated by photochemistry, characteristic upslope–downslope circulation and planetary boundary layer (PBL) dynamics. Significant day-to-day variations are found for all species due to the effect of regional transport and changes in synoptic pattern analysed with the backward propagation approach based on HYSPLIT trajectories. Low pollution was often observed for air masses from the north-west (behind cold fronts), and high pollution was observed from the southern areas such as industrialized Wu'an. The contribution of regional transport for the pollutants measured at the site during the observation period was estimated to be about 20 % to 30 % for trace gases and about 50 % for aerosols. In addition, agricultural burning events impacted the day-to-day variations in HCHO, CHOCHO and aerosols. It needs to be noted that although several MAX-DOAS measurements of trace gases and aerosols in the NCP area have been reported in previous studies, this study is the first work to derive a comprehensive set of vertical profiles of NO2, SO2, HONO, HCHO, CHOCHO and aerosols from measurements of one MAX-DOAS instrument. Also, so far, the validation of MAX-DOAS profile results by comparison with various surface in situ measurements as well as profile measurements from lidar and aircraft is scarce. Moreover, the backward propagation approach for characterizing the contributions of regional transport of pollutants from different regions was applied to the MAX-DOAS results of trace gases and aerosols for the first time.

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.

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