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

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.

2018 ◽  
Vol 18 (23) ◽  
pp. 17177-17190 ◽  
Author(s):  
Peng Sun ◽  
Wei Nie ◽  
Xuguang Chi ◽  
Yuning Xie ◽  
Xin Huang ◽  
...  

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.


2018 ◽  
Author(s):  
Peng Sun ◽  
Wei Nie ◽  
Xuguang Chi ◽  
Yuning Xie ◽  
Xin Huang ◽  
...  

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 nitrate for two 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 two times higher than those in summer mainly due to different meteorological conditions. In summer, the diurnal variation of particulate nitrate was determined by the thermodynamic equilibrium, resulting in a much lower concentration during daytime despite of a considerable photochemical production. Air masses from polluted YRD and biomass burning region contributed to the high nitrate concentration during summer. In winter, particulate nitrate didn’t reveal an evident diurnal variation. Regional transport from northern China played an important role in enhancing nitrate concentration. Eighteen 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 percent 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 YRD during winter, and illustrated the urgent needs to control the NOx emission.


2020 ◽  
Vol 194 ◽  
pp. 04058
Author(s):  
Dongqing Fang ◽  
Junli Jin ◽  
Wei Huang ◽  
Yong Zhang ◽  
Wanqi Sun ◽  
...  

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.


2011 ◽  
Vol 402 ◽  
pp. 860-863
Author(s):  
Bin Jiang

In this paper, aerosol samples were collected with Andersen cascade sampler on typical polluted days at residential area in Hangzhou, China. The concentrations of sulfate, nitrate and ammonium in aerosol were analyzed by the ion chromatography. Results showed the concentrations of SO42-, NO3- and NH4+ on polluted days were 21.4, 31.2 and 10.8µg m-3 in fine particles, respectively, and were 1.3-1.7 times higher than on unpolluted days. SO42-, NO3- and NH4+ in fine particles were the main threat of athlete health in the urban area of Yangtze River delta.


Atmosphere ◽  
2020 ◽  
Vol 11 (7) ◽  
pp. 720
Author(s):  
Li Xia ◽  
Bin Zhu ◽  
Honglei Wang ◽  
Hanqing Kang ◽  
Junlin An

Regional-scale field observations of fine particles (PM2.5) were carried out at urban, suburban and regional background sites across the Yangtze River Delta (YRD) from 15–30 January 2015. The coefficients of divergence (CD) values reveal the similarity of dataset at the three sites. The PM2.5 concentrations and meteorological data exhibit temporal synchronization. From January 15 to 26, the YRD experienced severe PM2.5 pollution resulting from a cold front moving through and high-pressure control. Then, a 4-day intermittent rain event from 27–30 January significantly scavenged PM2.5. For the chemical components in PM2.5, secondary inorganic ions were dominant, and they accounted for larger proportions at the urban and suburban sites than at the regional background site. The OC/EC ratios were higher in daytime than at night, and were lower on polluted days than on clean (rainy) days. The principal sources of PM2.5 were secondary nitrate (38%) and sulfate (23%) formation, biomass burning (14%), and marine source (8%). Marine (16%) and sulfate (30%) sources were enhanced on clean (rainy) days, indicating the notable effect of marine air masses on PM2.5 chemical components. The open burning source contribution at the regional site was the largest during the polluted period because more air masses arrived from combustion zones.


2017 ◽  
Vol 55 ◽  
pp. 146-156 ◽  
Author(s):  
Yongjie Yang ◽  
Rui Zhou ◽  
Yue Yu ◽  
Yan Yan ◽  
Yan Liu ◽  
...  

2020 ◽  
Vol 98 ◽  
pp. 62-70 ◽  
Author(s):  
Qi Yuan ◽  
Xiaomi Teng ◽  
Shaoxuan Tu ◽  
Binxin Feng ◽  
Zhiyu Wu ◽  
...  

Atmosphere ◽  
2021 ◽  
Vol 12 (8) ◽  
pp. 990
Author(s):  
Yi Huang ◽  
Li Wang ◽  
Xin Cheng ◽  
Jinjin Wang ◽  
Ting Li ◽  
...  

Air pollution is becoming increasingly serious along with social and economic development in the southwest of China. The distribution characteristics of particle matter (PM) were studied in Chengdu from 2016 to 2017, and the changes of PM bearing water-soluble ions and heavy metals and the distribution of secondary ions were analyzed during the haze episode. The results showed that at different pollution levels, heavy metals were more likely to be enriched in fine particles and may be used as a tracer of primary pollution sources. The water-soluble ions in PM2.5 were mainly Sulfate-Nitrate-Ammonium (SNA) accounting for 43.02%, 24.23%, 23.50%, respectively. SO42−, NO3−, NH4+ in PM10 accounted for 34.56%, 27.43%, 19.18%, respectively. It was mainly SO42− in PM at Clean levels (PM2.5 = 0~75 μg/m3, PM10 = 0~150 μg/m3), and mainly NH4+ and NO3− at Light-Medium levels (PM2.5 = 75~150 μg/m3, PM10 = 150~350 μg/m3). At Heavy levels (PM2.5 = 150~250 μg/m3, PM10 = 350~420 μg/m3), it is mainly SO42− in PM2.5, and mainly NH4+ and NO3− in PM10. The contribution of mobile sources to the formation of haze in the study area was significant. SNA had significant contributions to the PM during the haze episode, and more attention should be paid to them in order to improve air quality.


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