In situ continuous hourly observations of wintertime nitrate, sulfate and ammonium in a megacity in the North China plain from 2014 to 2019: Temporal variation, chemical formation and regional transport

Chemosphere ◽  
2021 ◽  
Vol 262 ◽  
pp. 127745 ◽  
Author(s):  
Miao Tang ◽  
Yu Liu ◽  
Jun He ◽  
Zhe Wang ◽  
Zhijun Wu ◽  
...  
Keyword(s):  
Temporal Variation ◽  
North China Plain ◽  
North China ◽  
Regional Transport ◽  
The North ◽  
The North China Plain

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 Distribution and Sources of Air pollutants in the North China Plain Based on On-Road Mobile Measurements

2016 ◽  
Author(s):  
Yi Zhu ◽  
Jiping Zhang ◽  
Junxia Wang ◽  
Wenyuan Chen ◽  
Yiqun Han ◽  
...  
Keyword(s):  
Air Pollutants ◽  
Ultrafine Particles ◽  
North China Plain ◽  
North China ◽  
Regional Transport ◽  
Large Cities ◽  
Model Studies ◽  
The North ◽  
The North China Plain ◽  
Local Emissions

Abstract. The North China Plain (NCP) has been experiencing severe air pollution problems with rapid economic growth and urbanisation. Many field and model studies have examined the distribution of air pollutants in the NCP, but convincing results have not been achieved mainly due to a lack of direct measurements of pollutants over large areas. Here, we employed a mobile laboratory to observe the main air pollutants in a large part of the NCP from June 11 to July 15, 2013. High median concentrations of sulphur dioxide (SO2) (12 ppb), nitrogen oxides (NOx) (NO + NO2; 452 ppb), carbon monoxide (CO) (956 ppb), black carbon (BC; 5.5 μg m−3) and ultrafine particles (28 350 cm−3) were measured. Most of the high values, i.e., 95 percentile concentrations, were distributed near large cities, suggesting the influence of local emissions. In addition, we analysed the regional transport of SO2 and CO, relatively long-lived pollutants, based on our mobile observations together with wind field and satellite data analyses. Our results suggested that, for border areas of the NCP, wind from outside would have a diluting effect on pollutants, while south winds would bring in pollutants accumulated during transport through other parts of the NCP. For the central NCP, the concentrations of pollutants were likely to remain at high levels, partly due to the influence of regional transport by prevalent south–north winds over the NCP and partly by local emissions.

scholarly journals Aerosol optical properties in the North China Plain during HaChi campaign: an in-situ optical closure study

2011 ◽  
Vol 11 (12) ◽  
pp. 5959-5973 ◽  
Author(s):  
N. Ma ◽  
C. S. Zhao ◽  
A. Nowak ◽  
T. Müller ◽  
S. Pfeifer ◽  
...  
Keyword(s):  
Optical Properties ◽  
North China Plain ◽  
North China ◽  
Scattering Coefficient ◽  
Aerosol Optical Properties ◽  
Mean Values ◽  
The North ◽  
The North China Plain ◽  
The Mean

Abstract. The largest uncertainty in the estimation of climate forcing stems from atmospheric aerosols. In early spring and summer of 2009, two periods of in-situ measurements on aerosol physical and chemical properties were conducted within the HaChi (Haze in China) project at Wuqing, a town between Beijing and Tianjin in the North China Plain (NCP). Aerosol optical properties, including the scattering coefficient (σsp), the hemispheric back scattering coefficient (σbsp), the absorption coefficient (σap), as well as the single scattering albedo (ω), are presented. The diurnal and seasonal variations are analyzed together with meteorology and satellite data. The mean values of σsp, 550 nm of the dry aerosol in spring and summer are 280±253 and 379±251 Mm−1, respectively. The average σap for the two periods is respectively 47±38 and 43±27 Mm−1. The mean values of ω at the wavelength of 637 nm are 0.82±0.05 and 0.86±0.05 for spring and summer, respectively. The relative high levels of σsp and σbsp are representative of the regional aerosol pollution in the NCP. Pronounced diurnal cycle of $σsp, σap and ω are found, mainly influenced by the evolution of boundary layer and the accumulation of local emissions during nighttime. The pollutants transported from the southwest of the NCP are more significant than that from the two megacities, Beijing and Tianjin, in both spring and summer. An optical closure experiment is conducted to better understand the uncertainties of the measurements. Good correlations (R>0.98) are found between the values measured by the nephelometer and the values calculated with a modified Mie model. The Monte Carlo simulation shows an uncertainty of about 30 % for the calculations. Considering all possible uncertainties of measurements, calculated σsp and σbsp agree well with the measured values, indicating a stable performance of instruments and thus reliable aerosol optical data.

Estimating the contribution of regional transport to PM 2.5 air pollution in a rural area on the North China Plain

2017 ◽  
Vol 583 ◽  
pp. 280-291 ◽  
Author(s):  
Dongsheng Chen ◽  
Xiangxue Liu ◽  
Jianlei Lang ◽  
Ying Zhou ◽  
Lin Wei ◽  
...  
Keyword(s):  
Air Pollution ◽  
Rural Area ◽  
North China Plain ◽  
North China ◽  
Regional Transport ◽  
Pm 2.5 ◽  
The North ◽  
The North China Plain

scholarly journals Aerosol optical properties in the North China Plain during HaChi campaign: an in-situ optical closure study

2011 ◽  
Vol 11 (3) ◽  
pp. 9567-9605 ◽  
Author(s):  
N. Ma ◽  
C. S. Zhao ◽  
A. Nowak ◽  
T. Müller ◽  
S. Pfeifer ◽  
...  
Keyword(s):  
Optical Properties ◽  
North China Plain ◽  
North China ◽  
Aerosol Optical Properties ◽  
Mean Values ◽  
The North ◽  
The North China Plain ◽  
The Mean ◽  
Local Emissions

Abstract. The largest uncertainty in the estimation of radiative forcings on climate stems from atmospheric aerosols. In winter and summer of 2009, two periods of in-situ measurements on aerosol physical and chemical properties were conducted within the HaChi project at Wuqing, a town between Beijing and Tianjin in the North China Plain (NCP). Aerosol optical properties including scattering coefficient (σsp), hemispheric back scattering coefficient (σbsp), absorption coefficient (σap, as well as single scattering albedo (ω) are presented. The characteristics of diurnal and seasonal variations are analyzed together with the meteorological and satellite data. The mean values of σsp, 550 nm of the dry aerosol in winter and summer are 280 ± 253 and 379 ± 251 Mm−1, respectively. The average σap for the two periods are respectively 47 ± 38 and 43 ± 27 Mm−1. The mean values of ω are 0.83 ± 0.05 and 0.87 ± 0.05 for winter and summer, respectively. The relative high levels of σsp and σbsp are representative of the regional polluted aerosol of the North China Plain. Pronounced diurnal cycle of σsp, σap and ω are found, mainly influenced by the evolution of boundary layer and accumulation of local emissions during night-time. Regional transport of pollutants from southwest in the NCP is significant both in winter and summer, while high values of σsp and σap correlate with calm winds in winter, which indicating the significant contribution of local emissions. An optical closure experiment is conducted to better understand uncertainties of the measurements. Good correlations (R>0.98) are found between values measured by nephelometer and values calculated with a modified Mie model. Monte Carlo simulations show an uncertainty of about 30% for the calculations. Considering all possible uncertainties of measurements, calculated σsp and σbsp agree well with measured values, indicating a stable performance of instruments and thus a reliable aerosol optical data.

scholarly journals Seasonal variations in the highly time-resolved aerosol composition, sources and chemical processes of background submicron particles in the North China Plain

2021 ◽  
Vol 21 (6) ◽  
pp. 4521-4539
Author(s):  
Jiayun Li ◽  
Liming Cao ◽  
Wenkang Gao ◽  
Lingyan He ◽  
Yingchao Yan ◽  
...  
Keyword(s):  
Oxidation State ◽  
Seasonal Variations ◽  
North China Plain ◽  
North China ◽  
Organic Aerosol ◽  
Submicron Particles ◽  
Regional Transport ◽  
The North ◽  
The North China Plain ◽  
Four Seasons

Abstract. For the first time in the North China Plain (NCP) region, we investigated the seasonal variations in submicron particles (NR-PM1) and their chemical composition at a background mountainous site of Xinglong using an Aerodyne high-resolution time-of-flight aerosol mass spectrometer. The average concentration of NR-PM1 was highest in autumn (15.1 µg m−3) and lowest in summer (12.4 µg m−3), with a greater abundance of nitrate in spring (34 %), winter (31 %) and autumn (34 %) and elevated organics (40 %) and sulfate (38 %) in summer. PM1 in Xinglong showed higher acidity in summer and moderate acidity in spring, autumn and winter, with average pH values of 2.7±0.6, 4.2±0.7, 3.5±0.5 and 3.7±0.6, respectively, which is higher than those estimated in the United States and Europe. The size distribution of all PM1 species showed a consistent accumulation mode peaking at approximately 600–800 nm (dva), indicating a highly aged and internally mixed nature of the background aerosols, which was further supported by the source appointment results using positive matrix factorization and multilinear engine analysis. Significant contributions of aged secondary organic aerosol (SOA) in organic aerosol (OA) were resolved in all seasons (>77 %), especially in summer. The oxidation state and the process of evolution of OAs in the four seasons were further investigated, and an enhanced carbon oxidation state (−0.45–0.10) and O/C (0.54–0.75) and OM/OC (1.86–2.13) ratios – compared with urban studies – were observed, with the highest oxidation state appearing in summer, likely because of the relatively stronger photochemical processing that dominated the formation processes of both less oxidized OA (LO-OOA) and more oxidized OA (MO-OOA). Aqueous-phase processing also contributed to the SOA formation and prevailed in winter, with the share to MO-OOA being more important than that to LO-OOA. In addition, regional transport also played an important role in the variations in SOA. Especially in summer, continuous increases in SOA concentration as a function of odd oxygen (Ox=O3+NO2) were found to be associated with the increases in wind speed. Furthermore, backward trajectory analysis showed that higher concentrations of submicron particles were associated with air masses transported short distances from the southern regions in all four seasons, while long-range transport from Inner Mongolia (western and northern regions) also contributed to summertime particulate pollution in the background areas of the NCP. Our results illustrate that the background particles in the NCP are influenced significantly by aging processes and regional transport, and the increased contribution of aerosol nitrate highlights how regional reductions in nitrogen oxide emissions are critical for remedying occurrence of nitrate-dominated haze events over the NCP.

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