scholarly journals Size Distributions of Water-Soluble Inorganic Ions in Atmospheric Aerosols During the Meiyu Period in the Yangtze River Delta, China

2021 ◽  
Vol 9 ◽  
Author(s):  
Zhaoye Wu ◽  
Duanyang Liu ◽  
Tianliang Zhao ◽  
Yan Su ◽  
Bin Zhou
Keyword(s):  
Particle Size ◽  
Fine Particles ◽  
Inorganic Ions ◽  
Bimodal Distribution ◽  
Yangtze River Delta ◽  
Water Soluble ◽  
The North ◽  
Water Soluble Inorganic Ions ◽  
Oxidation Ratio ◽  
Mass Concentrations

In order to investigate the chemical composition distributions and pollution characteristics of Total water-soluble inorganic ions (TWSII) in the rain period (Meiyu) in the East Asian summer monsoon season, including the impact of Meiyu on air pollution in the Yangtze River Delta, East China, the gaseous pollutant concentrations, the 9 sizes segregated particles, and water-soluble inorganic ions of aerosols were measured on the north shore of Taihu Lake from June 4 to July 5, 2016. Results show that the mass concentrations of atmospheric particulate matters (PM2.5 and PM10) and main gaseous pollutants (SO2, NO2, CO, and O3) decrease during the Meiyu period, with the largest decline in PM10 and the smallest in CO. TWSII in atmospheric particles are mainly concentrated in fine particles during the Meiyu period. The values of ρ (TWSII) for PM1.1, PM1.1–2.1, and PM2.1–10 before the Meiyu onset are generally greater than those during the Meiyu period. During the first pollution process, the ρ(TWSII) for PM1.1 and PM1.1–2.1 first increase to the peak values, and then decrease during the moderate rainfall period, when the ρ(TWSII) in PM2.1–10 increase to its maximum before the Meiyu onset. The mass concentrations for anions, cations, and total ions at different particle-size sections all exhibit bimodal distributions before and after the Meiyu onset. The mass concentration peaks at a particle size of 1.1–2.1 μm for fine particles, while at 5.8–9.0 μm (before the Meiyu onset) and 9.0–10.0 μm (during the Meiyu period) for coarse particles, respectively. The peak particle size for mass concentration of coarse particles moves toward larger sizes during the Meiyu period. The mass concentrations of SO42− at different particle-size sections show a bimodal distribution before the Meiyu onset and a multi-modal distribution during the Meiyu period. The mass concentrations of NO3− at different particle-size sections show a bimodal distribution before the Meiyu onset and a unimodal distribution during the Meiyu period. The mass concentrations of NH4+ at different particle-size sections present a bimodal distribution before and after the Meiyu onset, with the particle-size for peak concentrations distributing in 1.1–2.1 and 5.8–9.0 μm before the Meiyu onset, and 9.0–10.0 μm during the Meiyu period. The mean value of nitrogen oxidation ratio (NOR) is higher before the Meiyu onset than after, indicating that the secondary conversion of NO2 before the Meiyu onset is enhanced. The sulfur oxidation ratio (SOR) values are greater than NOR values, but the concentrations of NO2 in the same period during the Meiyu period are higher than those of SO2, which indicates that the secondary conversion of SO2 during the Meiyu period on the north bank of Taihu Lake is stronger than that of NO2. During the whole observation, the contribution of stationary sources mainly contributed to the atmospheric particulate matters during the Meiyu period. The contributions of vehicle exhaust and coal combustion to fine particles are more obviously affected by the changes in meteorological conditions during the Meiyu period, and the vehicle emissions contribute more to PM1.1–2.1 than to PM1.1.

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.

scholarly journals Particle size-dependent fluorescence properties of water-soluble organic compounds (WSOC) and their atmospheric implications on the aging of WSOC

2021 ◽  
Author(s):  
Juanjuan Qin ◽  
Jihua Tan ◽  
Xueming Zhou ◽  
Yanrong Yang ◽  
Yuanyuan Qin ◽  
...  
Keyword(s):  
Particle Size ◽  
Organic Compounds ◽  
Fine Particles ◽  
Stokes Shift ◽  
Bimodal Distribution ◽  
Dominant Mode ◽  
Water Soluble ◽  
Atmospheric Particle ◽  
Humification Degree ◽  
Transformation Processes

Abstract. Water-soluble organic compounds (WSOC) are essential in atmospheric particle formation, migration, and transformation processes. Size-segregated atmospheric particles were collected in a rural area of Beijing. Excitation-emission matrix (EEM) fluorescence spectroscopy was used to investigate the sources and optical properties of WSOC. Sophisticated data analysis on EEM data was performed to characteristically estimate the underlying connections among aerosol particles in different sizes. The WSOC concentrations and average fluorescence intensity (AFI) showed monomodal distribution in winter and bimodal distribution in summer, with dominant mode between 0.26 to 0.44 µm for both seasons. The EEM spectra of size-segregated WSOC were different among variant particle sizes, which could be the results of changing sources and/or chemical transformation of organics. Size distributions of fluorescence regional intensity (region Ⅲ and Ⅴ) and HIX indicate that humification degree or aromaticity of WSOC was highest between 0.26 to 0.44 µm. The Stokes shift (SS) and the harmonic mean of the excitation and emission wavelengths (WH) reflected that π-conjugated systems were high between 0.26 to 0.44 µm as well. The parallel factor analysis (PARAFAC) results showed that humic-like substances were abundant in fine particles (< 1 µm) and peaked at 0.26–0.44 µm. All evidence supported that the humification degree of WSOC increased in submicron mode (< 0.44 µm) and decreased gradually. Thus, it was conjectured that condensation of organics still goes on in submicron mode, resulting in the highest humification degree exhibit in particle size between 0.26 to 0.44 µm rather than < 0.26 µm. Synthetically analyzing 3-dimensional fluorescence data could efficiently present the secondary transformation processes of WSOC.

scholarly journals Characteristics of PM2.5 Chemical Compositions and Their Effect on Atmospheric Visibility in Urban Beijing, China during the Heating Season

2018 ◽  
Vol 15 (9) ◽  
pp. 1924 ◽  
Author(s):  
Xing Li ◽  
Shanshan Li ◽  
Qiulin Xiong ◽  
Xingchuan Yang ◽  
Mengxi Qi ◽  
...  
Keyword(s):  
Fine Particles ◽  
Inorganic Ions ◽  
Water Soluble ◽  
Motor Vehicles ◽  
Urban Site ◽  
Chemical Compositions ◽  
Heating Season ◽  
Atmospheric Visibility ◽  
Visibility Impairment ◽  
Mass Concentrations

Beijing, which is the capital of China, suffers from severe Fine Particles (PM2.5) pollution during the heating season. In order to take measures to control the PM2.5 pollution and improve the atmospheric environmental quality, daily PM2.5 samples were collected at an urban site from 15 November to 31 December 2016, characteristics of PM2.5 chemical compositions and their effect on atmospheric visibility were analyzed. It was found that the daily average mass concentrations of PM2.5 ranged from 7.64 to 383.00 μg m−3, with an average concentration of 114.17 μg m−3. On average, the Organic Carbon (OC) and Elemental Carbon (EC) contributed 21.39% and 5.21% to PM2.5, respectively. Secondary inorganic ions (SNA: SO42− + NO3− + NH4+) dominated the Water-Soluble Inorganic Ions (WSIIs) and they accounted for 47.09% of PM2.5. The mass concentrations of NH4+, NO3− and SO42− during the highly polluted period were 8.08, 8.88 and 6.85 times greater, respectively, than during the clean period, which contributed most to the serious PM2.5 pollution through the secondary transformation of NO2, SO2 and NH3. During the highly polluted period, NH4NO3 contributed most to the reconstruction extinction coefficient (b′ext), accounting for 35.7%, followed by (NH4)2SO4 (34.44%) and Organic Matter (OM: 15.24%). The acidity of PM2.5 in Beijing was weakly acid. Acidity of PM2.5 and relatively high humidity could aggravate PM2.5 pollution and visibility impairment by promoting the generation of secondary aerosol. Local motor vehicles contributed the most to NO3−, OC, and visibility impairment in urban Beijing. Other sources of pollution in the area surrounding urban Beijing, including coal burning, agricultural sources, and industrial sources in the Hebei, Shandong, and Henan provinces, released large amounts of SO2, NH3, and NO2. These, which were transformed into SO42−, NH4+, and NO3− during the transmission process, respectively, and had a great impact on atmospheric visibility impairment.

scholarly journals Dominant Contributions of Secondary Aerosols and Vehicle Emissions to Water-Soluble Inorganic Ions of PM2.5 in an Urban Site in the Metropolitan Hangzhou, China

Atmosphere ◽  
2021 ◽  
Vol 12 (11) ◽  
pp. 1529
Author(s):  
Chun Xiong ◽  
Shaocai Yu ◽  
Xue Chen ◽  
Zhen Li ◽  
Yibo Zhang ◽  
...  
Keyword(s):  
Vehicle Emissions ◽  
Inorganic Ions ◽  
Water Soluble ◽  
Urban Site ◽  
Online Systems ◽  
Seasonal Characteristics ◽  
Water Soluble Inorganic Ions ◽  
Secondary Aerosols ◽  
The Mean ◽  
Mass Concentrations

Water soluble inorganic ions (WSIIs) are important components in PM2.5 and could strongly affect the acidity and hygroscopicity of PM2.5. In order to achieve the seasonal characteristics and determine the potential sources of WSIIs in PM2.5 in Hangzhou, online systems were used to measure hourly mass concentrations of WSIIs (SO42–, NO3–, NH4+, Cl–, Na+, K+, Ca2+ and Mg2+) as well as PM2.5, NO2 and SO2 at an urban site for one month each season (May, August, October, December) in 2017. Results showed that the hourly mass concentrations of PM2.5 during the whole campaign varied from 1 to 292 μg·m−3 with the mean of 56.03 μg·m−3. The mean mass concentration of WSIIs was 26.49 ± 20.78 μg·m−3, which contributed 48.28% to averaged PM2.5 mass. SNA (SO42–, NO3– and NH4+) were the most abundant ions in PM2.5 and on average, they comprised 41.57% of PM2.5 mass. PM2.5, NO2, SO2 and WSIIs showed higher mass concentrations in December, possibly due to higher energy consumption emissions, unfavorable meteorological factors (e.g., lower wind speed and temperature) and regional transport. Results from PCA models showed that secondary aerosols and vehicle emissions were the dominant sources of WSIIs in the observations. Our findings highlight the importance of stronger controls on precursor (e.g., SO2 and NO2) emissions in Hangzhou, and show that industrial areas should be controlled at local and regional scales in the future.

scholarly journals Characterization of the size-segregated water-soluble inorganic ions at eight Canadian rural sites

2008 ◽  
Vol 8 (4) ◽  
pp. 13801-13845 ◽  
Author(s):  
L. Zhang ◽  
R. Vet ◽  
A. Wiebe ◽  
C. Mihele ◽  
B. Sukloff ◽  
...  
Keyword(s):  
Warm Season ◽  
Inorganic Ions ◽  
Base Cations ◽  
Bimodal Distribution ◽  
Cold Season ◽  
Water Soluble ◽  
The Other ◽  
Size Distributions ◽  
Order Of Magnitude ◽  
Water Soluble Inorganic Ions

Abstract. Size-segregated water-soluble inorganic ions, including particulate sulphate (SO42-), nitrate (NO3-), ammonium (NH4+), chloride (Cl-) and base cations (K+, Na+, Mg2+, Ca2+), were measured using a Micro-Orifice Uniform Deposit Impactor (MOUDI) during fourteen short-term field campaigns at eight locations in both polluted and remote regions of eastern and central Canada. The size distributions of SO42- and NH4+ were unimodal, peaking at 0.3–0.6 μm in diameter, during most of the campaigns, although a bimodal distribution was found during one campaign and a trimodal distribution during another campaign made at a coastal site. The size distributions of NO3- were unimodal, peaking at 4.0–7.0 μm, during the warm-season campaigns and bimodal, with one peak at 0.3–0.6 μm and another at 4–7 μm, during the cold-season campaigns. A unimodal size distribution, peaking at 4–6 μm, was found for Cl-, Na+, Mg2+ and Ca2+ during approximately half of the campaigns and a bimodal distribution, with one peak at 2 μm and the other at 6 μm, was found during the rest of the campaigns. For K+, a bimodal distribution, with one peak at 0.3 μm and the other at 4 μm, was observed during most of the campaigns. The measured ion concentrations varied by one order of magnitude across the various sites. The air-mass origins and meteorological conditions both played important roles in formulating the observed geographical and seasonal patterns of these ion species concentration levels, size distributions and fine particle acidity.

scholarly journals Characterization of the size-segregated water-soluble inorganic ions at eight Canadian rural sites

2008 ◽  
Vol 8 (23) ◽  
pp. 7133-7151 ◽  
Author(s):  
L. Zhang ◽  
R. Vet ◽  
A. Wiebe ◽  
C. Mihele ◽  
B. Sukloff ◽  
...  
Keyword(s):  
Inorganic Ions ◽  
Bimodal Distribution ◽  
Meteorological Conditions ◽  
Water Soluble ◽  
The Other ◽  
Submicron Particles ◽  
Emission Sources ◽  
Size Distributions ◽  
Nucleation Mode ◽  
Water Soluble Inorganic Ions

Abstract. Size-segregated water-soluble inorganic ions, including particulate sulphate (SO42-), nitrate (NO3-), ammonium (NH4+), chloride (Cl-), and base cations (K+, Na+, Mg2+, Ca2+), were measured using a Micro-Orifice Uniform Deposit Impactor (MOUDI) during fourteen short-term field campaigns at eight locations in both polluted and remote regions of eastern and central Canada. The size distributions of SO42- and NH4+ were unimodal, peaking at 0.3–0.6 µm in diameter, during most of the campaigns, although a bimodal distribution was found during one campaign and a trimodal distribution was found during another campaign made at a coastal site. SO42- peaked at slightly larger sizes in the cold seasons (0.5–0.6 µm) compared to the hot seasons (0.3–0.4 µm) due to the higher relative humidity in the cold seasons. The size distributions of NO3- were unimodal, peaking at 4.0–7.0 µm during the warm-season campaigns, and bimodal, with one peak at 0.3–0.6 µm and another at 4–7 µm during the cold-season campaigns. A unimodal size distribution, peaking at 4–6 µm, was found for Cl-, Na+, Mg2+, and Ca2+ during approximately half of the campaigns and a bimodal distribution, with one peak at 2 µm and the other at 6 µm, was found during the rest of the campaigns. For K+, a bimodal distribution, with one peak at 0.3 µm and the other at 4 µm, was observed during most of the campaigns. Seasonal contrasts in the size-distribution profiles suggest that emission sources and air mass origins were the major factors controlling the size distributions of the primary aerosols while meteorological conditions were more important for the secondary aerosols. The dependence of the particle acidity on the particle size from the nucleation mode to the accumulation mode was not consistent from site to site or from season to season. Particles in the accumulation mode were more acidic than those in the nucleation mode when submicron particles were in the state of strong acidity; however, when submicron particles were neutral or weakly acidic, particles in the nucleation mode could sometimes be more acidic. The inconsistency of the dependence of the particle acidity on the particle size should have been caused by the different emission sources of all the related species and the different meteorological conditions during the different campaigns. The results presented here at least partially explain the controversial phenomenon found in previous studies on this topic.

Water-soluble inorganic ions of size-differentiated atmospheric particles from a suburban site of Mexico City

2017 ◽  
Vol 75 (2) ◽  
pp. 155-169 ◽  
Author(s):  
Telma Castro ◽  
Oscar Peralta ◽  
Dara Salcedo ◽  
José Santos ◽  
María I. Saavedra ◽  
...  
Keyword(s):  
Mexico City ◽  
Inorganic Ions ◽  
Atmospheric Particles ◽  
Water Soluble ◽  
Water Soluble Inorganic Ions ◽  
Suburban Site
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