scholarly journals Online Measurement of PM2.5 at an Air Monitoring Supersite in Yangtze River Delta: Temporal Variation and Source Identification

Atmosphere ◽  
2020 ◽  
Vol 11 (8) ◽  
pp. 789 ◽  
Author(s):  
Lian Duan ◽  
Lei Yan ◽  
Guangli Xiu
Keyword(s):  
Yangtze River ◽  
Chemical Species ◽  
Inorganic Ions ◽  
Ambient Air ◽  
Yangtze River Delta ◽  
River Delta ◽  
Water Soluble ◽  
Dianshan Lake ◽  
Haze Pollution ◽  
High Level

To comprehensively explore the transport of air pollutants, one-year continuous online observation of PM2.5 was conducted from 1 April 2015 to 31 March 2016 at Dianshan Lake, a suburban junction at the central of Yangtze River Delta. The chemical species of PM2.5 samples mainly focused on Organic carbon (OC), Elemental carbon (EC) and Water-Soluble Inorganic Ions (WSIIs). The annual average of PM2.5 concentration was 59.8 ± 31.7 µg·m−3, 1.7 times higher than the Chinese National Ambient Air Quality Standards (CNAAQS) (35 µg·m−3). SNA (SO42−, NO3− and NH4+) was the most dominated species of PM2.5 total WSIIs, accounting for 51% of PM2.5. PM2.5 and all of its chemical species shared the same seasonal variations with higher concentration in winter and spring, lower in autumn and summer. The higher NO3−/EC and NOR occurred in winter suggested that intensive secondary formation of nitrate contributed to the higher levels of PM2.5. Cluster analysis based on 72-h backward air trajectory showed that the air mass cluster from nearby inland cities, including Zhejiang, Anhui and Jiangxi Provinces contributed mostly to the total trajectories. Furtherly, potential source contribution function (PSCF) analysis revealed that local sources, namely the emissions in the Yangtze River, were the primary sources. During haze pollution, NO3− was the most important fraction of PM2.5 and the heterogeneous formation of nitrate became conspicuous. All the results suggested that the anthropogenic emissions (such as traffic exhaust) was responsible for the relatively high level of PM2.5 at this monitoring station.

scholarly journals Two years of online measurement of fine particulate nitrate in the western Yangtze River Delta: influences of thermodynamics and N<sub>2</sub>O<sub>5</sub> hydrolysis

2018 ◽  
Vol 18 (23) ◽  
pp. 17177-17190 ◽  
Author(s):  
Peng Sun ◽  
Wei Nie ◽  
Xuguang Chi ◽  
Yuning Xie ◽  
Xin Huang ◽  
...  
Keyword(s):  
Diurnal Variation ◽  
Yangtze River ◽  
Nitrate Concentration ◽  
Yangtze River Delta ◽  
River Delta ◽  
Water Soluble ◽  
Online Measurement ◽  
High Concentration ◽  
Soluble Ions ◽  
Water Soluble Ions

Abstract. Particulate nitrate contributes a large fraction of secondary aerosols. Despite understanding of its important role in regional air quality and global climate, long-term continuous measurements are rather limited in China. In this study, we conducted online measurement of PM2.5 (particulate matter with diameters less than 2.5 µm) nitrate for 2 years from March 2014 to February 2016 using the Monitor for AeRosols and Gases in ambient Air (MARGA) in the western Yangtze River Delta (YRD), eastern China, and investigate the main factors that influenced its temporal variations and formation pathways. Compared to other sites in China, an overall high concentration of particulate nitrate was observed, with a mean value of 15.8 µg m−3 (0.5 to 92.6 µg m−3). Nitrate on average accounted for 32 % of the total mass of water-soluble ions and the proportion increased with PM loading, indicating that nitrate is a major driver of haze pollution episodes in this region. Sufficient ammonia drove most nitrate into the particle phase in the form of ammonium nitrate. A typical seasonal cycle of nitrate was observed, with the concentrations in winter on average 2 times higher than those in summer mainly due to different meteorological conditions. In summer, the diurnal variation of particulate nitrate was determined by thermodynamic equilibrium, resulting in a much lower concentration during daytime despite a considerable photochemical production. Air masses from the polluted YRD and biomass burning region contributed to the high nitrate concentration during summer. In winter, particulate nitrate did not reveal an evident diurnal variation. Regional transport from northern China played an important role in enhancing nitrate concentration. A total of 18 nitrate episodes were selected to understand the processes that drive the formation of high concentration of nitrate. Rapid nitrate formation was observed during the pre-episode (the day before nitrate episode day) nights, and dominated the increase of total water-soluble ions. Calculated nitrate from N2O5 hydrolysis was highly correlated to and accounted for 80 % of the observed nitrate, suggesting that N2O5 hydrolysis was a major contributor to the nitrate episodes. Our results suggested that rapid formation of nitrate could be a main cause for extreme aerosol pollution events in the YRD during winter, and illustrated the urgent need to control NOx emission.

scholarly journals Characteristics and Sources of Black Carbon Aerosol in a Mega-City in the Western Yangtze River Delta, China

Atmosphere ◽  
2020 ◽  
Vol 11 (4) ◽  
pp. 315
Author(s):  
Jun Li ◽  
Lei Jiang ◽  
Cheng Chen ◽  
Dantong Liu ◽  
Songshan Du ◽  
...  
Keyword(s):  
Black Carbon ◽  
Coating Thickness ◽  
Yangtze River ◽  
Anthropogenic Activities ◽  
Chemical Species ◽  
Yangtze River Delta ◽  
River Delta ◽  
Traffic Emissions ◽  
Potential Contribution ◽  
Coated Particle

A single particle soot photometer (SP2) was deployed in urban Nanjing, located in the Yangtze River Delta (China), to investigate the mixing state and sources of ambient refractory black carbon (rBC) from 26 January to 25 February 2014, along with an in-situ measurement of submicron aerosol chemical species by an aerodyne aerosol chemical speciation monitor (ACSM). The results showed that anthropogenic activities associated with firework emissions can be a significant source for rBC-containing particles during the period of the Chinese New Year, resulting from the evident peaks of rBC at midnight. During the residual periods, namely regular day (RD), the diurnal cycles of rBC presented two typical peaks that can be attributed to a synergistic influence of local traffic emissions and boundary layer changes throughout a day. Three coating factors, including organics, sulfate, and nitrate (-rich), were resolved using a positive matrix factorization (PMF) approach to explain the potential contribution of non-rBC coatings (i.e., organics, sulfate, and nitrate) to the coating thickness of rBC-containing particles. As the results show, organic aerosols (OAs) might be a major contributor to the coating thickness of rBC-coating particles during the whole period. The relative coating thickness (a ratio between coated particle size to BC core) exhibited a positive relationship with sulfate, indicative of the favorable coating factor during the episode caused by firework emissions. Source apportionment of rBC was performed via a multiple linear regression between the total rBC mass and each ACSM-PMF factor (rBC-ACSM-PMF). On average, biomass burning emissions accounted for 43%, being the largest contributor during the RD period, whereas local traffic emissions played a major role during the new year time.

scholarly journals Does the Direct Settlement Policy of Trans-Provincial Outpatient Expenses Aggravate the Siphoning Effect? An Empirical Study on Yangtze River Delta, China

2021 ◽  
Vol 18 (19) ◽  
pp. 10001
Author(s):  
Li Li ◽  
Qingyu Zhou ◽  
Ting Yin ◽  
Zisheng Ji ◽  
Lufa Zhang
Keyword(s):  
Medical Treatment ◽  
Yangtze River ◽  
Yangtze River Delta ◽  
River Delta ◽  
Spatial Accessibility ◽  
Outpatient Visits ◽  
Yangtze River Delta Region ◽  
First Choice ◽  
Regional Medical ◽  
High Level

To solve the problem of reimbursing trans-regional medical expenses, using only cross-regional manual reimbursement but not direct medical insurance card settlement, China implemented a pilot policy of direct settlement of trans-provincial outpatient expenses (DSTOE) in the Yangtze River Delta region. Due to the differences in inter-regional medical development, patients often migrate from areas with low-level medical resources to the high-level areas, a phenomenon that we define as the “siphoning” of trans-regional patients, which can cause a variety of problems. To study whether DSTOE aggravates the siphoning effect, we analyzed the changes in the volume of trans-provincial outpatient visits and conducted a questionnaire survey and factor analysis on the willingness of trans-provincial medical treatment under DSTOE. Results showed that manual reimbursement was gradually replaced by direct settlement, while the total volume was not increased significantly, and the ratio of outpatient visits flowing into and out from Shanghai decreased. The majority of questionnaire respondents confessed that their willingness toward trans-regional medical treatment increased, while their first choice of medical location was still mainly local, with only a few indicating that they would directly choose a cross-regional, higher-level medical institution. Spatial accessibility significantly restricted the seeking of trans-regional medical treatment, whereas age, education level, and policy awareness served as significant protective factors for the choice of medical location. In conclusion, due to space accessibility constraints, insufficient policy coverage, and the rationale for choice of location, DSTOE did not aggravate the siphoning effect of trans-regional patients.

scholarly journals Seasonal variations of water-soluble ions in PM10 at a WMO/GAW station in the Yangtze River Delta, China

2020 ◽  
Vol 194 ◽  
pp. 04058
Author(s):  
Dongqing Fang ◽  
Junli Jin ◽  
Wei Huang ◽  
Yong Zhang ◽  
Wanqi Sun ◽  
...  
Keyword(s):  
Yangtze River ◽  
Inorganic Ions ◽  
Yangtze River Delta ◽  
Water Soluble ◽  
The Yangtze River ◽  
Soluble Ions ◽  
Water Soluble Ions ◽  
Water Soluble Inorganic Ions ◽  
Oxidation Ratio ◽  
The Yangtze River Delta

In order to understand the seasonal levels, formation mechanism and atmospheric chemical behaviours of water-soluble ions of PM10 in the Yangtze River Delta (YRD) region, aerosol samples were collected from January 2nd to December 28th, 2017 at a WMO/GAW regional background station in Lin’an. The concentrations of PM mass and nine water-soluble inorganic ions were obtained. The annual average concentration of PM10 was 59.9±33.9 μg m−3, lower than those reported in previous studies, indicating air quality of YRD region was improved. Nine water-soluble inorganic ions was accounted for 30.2-45.1% of the total PM mass, while ammonium (NH4+), sulfate (SO42+), as well as nitrate (NO3-) were the major ions which contributed 86.3% to total ions. The NO3- concentration was lowest in summer but highest in winter, suggesting it was likely influenced by thermodynamics. The levels of SO42- in spring and winter were related to photochemical reaction and regional transportation. Except for the SNA, Ca2+ was highest in four seasons likely due to sand storm and road fugitive dust. The annual mean ratio of [NO3-]/[SO42-] was nearly to 1, indicating mobile and stationary sources were equally important in Lin’an. The mean nitrogen oxidation ratio (NOR) and sulfur oxidation ratio (SOR) were 0.22±0.13 and 0.41±0.13, respectively, suggesting secondary formation was significant in the atmosphere at the background station of YRD region.

Characteristics of Water Soluble Ions in Atmospheric Aerosol on Clear and Hazy Days at Lin’an Regional Background Station, China

2011 ◽  
Vol 356-360 ◽  
pp. 2233-2238
Author(s):  
Hong Hui Xu ◽  
Jie Liu ◽  
Min Juan Mao ◽  
Jie Yao
Keyword(s):  
Atmospheric Aerosol ◽  
Yangtze River ◽  
Fine Particles ◽  
Yangtze River Delta ◽  
River Delta ◽  
Water Soluble ◽  
Coarse Particles ◽  
Regional Background ◽  
Soluble Ions ◽  
Water Soluble Ions

To investigate the characteristics of size distributions and water-soluble ions compositions of atmospheric aerosol in different weather conditions in the area of Yangtze River delta in China, aerosol samples were collected with Andersen cascade sampler on typical clear and hazy days at Lin’an regional background station. The water-soluble ionic concentrations were analyzed by the ion chromatography (IC). Results showed the concentrations of SO42-, NO3-, NH4+ and K+ on hazy days were 20.14, 17.45, 10.30, and 1.27µg m-3 in fine particles, respectively, and the concentrations of NO3-, NH4+ and K+ were 14.50, 2.35 and 0.50µg m-3 in coarse particles, respectively. This was 1.1-2.9 times higher than on clear days. The concentrations of Ca2+, Na+, Mg2+ and Cl- on hazy days were 2.67, 1.33, 0.37, and 1.03µg m-3 in fine particles, respectively, and the concentrations of Ca2+, Na+, Mg2+, Cl- and SO42- were 4.34, 1.27, 0.41, 0.89 and 2.08µg m-3 in coarse particles, respectively. This was 0.6-0.9 times lower than on clear days. K+ and secondary particles including sulfate, nitrate and ammonium came from the long-range transport which mainly from the area of Yangtze River delta, which was the main cause of formation of haze.

Long-term trend of haze pollution and impact of particulate matter in the Yangtze River Delta, China

2013 ◽  
Vol 182 ◽  
pp. 101-110 ◽  
Author(s):  
Zhen Cheng ◽  
Shuxiao Wang ◽  
Jingkun Jiang ◽  
Qingyan Fu ◽  
Changhong Chen ◽  
...  
Keyword(s):  
Particulate Matter ◽  
Yangtze River ◽  
Yangtze River Delta ◽  
River Delta ◽  
The Yangtze River ◽  
Term Trend ◽  
Haze Pollution ◽  
Long Term Trend ◽  
The Yangtze River Delta

scholarly journals Ozone and fine particle in the western Yangtze River Delta: an overview of 1 yr data at the SORPES station

2013 ◽  
Vol 13 (11) ◽  
pp. 5813-5830 ◽  
Author(s):  
A. J. Ding ◽  
C. B. Fu ◽  
X. Q. Yang ◽  
J. N. Sun ◽  
L. F. Zheng ◽  
...  
Keyword(s):  
Air Pollution ◽  
Air Quality ◽  
Yangtze River ◽  
Eastern China ◽  
Ambient Air ◽  
Yangtze River Delta ◽  
River Delta ◽  
Control Measures ◽  
Transport Pathway ◽  
The Yrd

Abstract. This work presents an overview of 1 yr measurements of ozone (O3) and fine particular matter (PM2.5) and related trace gases at a recently developed regional background site, the Station for Observing Regional Processes of the Earth System (SORPES), in the western part of the Yangtze River Delta (YRD) in eastern China. Ozone and PM2.5 showed strong seasonal cycles but with contrast patterns: O3 reached a maximum in warm seasons but PM2.5 in cold seasons. Correlation analysis suggests a VOC-sensitive regime for O3 chemistry and a formation of secondary aerosols under conditions of high O3 in summer. Compared with the National Ambient Air Quality Standards in China, our measurements report 15 days of O3 exceedance and 148 days of PM2.5 exceedance during the 1 yr period, suggesting a severe air pollution situation in this region. Case studies for typical O3 and PM2.5 episodes demonstrated that these episodes were generally associated with an air mass transport pathway over the mid-YRD, i.e., along the Nanjing–Shanghai axis with its city clusters, and showed that synoptic weather played an important role in air pollution, especially for O3. Agricultural burning activities caused high PM2.5 and O3 pollution during harvest seasons, especially in June. A calculation of potential source contributions based on Lagrangian dispersion simulations suggests that emissions from the YRD contributed to over 70% of the O3 precursor CO, with a majority from the mid-YRD. North-YRD and the North China Plain are the main contributors to PM2.5 pollution in this region. This work shows an important environmental impact from industrialization and urbanization in the YRD region, and suggests an urgent need for improving air quality in these areas through collaborative control measures among different administrative regions.

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