Ions In Atmospheric Aerosols Research Articles

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

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.

Atmospheric Deposition on the Southwest Coast of the Southern Basin of Lake Baikal

A precipitation monitoring station in Listvyanka was set up to determine the potential impact of the coastal area on the state of the adjacent air environment above Lake Baikal on its southwest coast. This article presents the results of studying the chemical composition of atmospheric deposition (aerosols and precipitation) at this station in 2020, and of their comparison with the data from previous years (from 2000 to 2019). In 2020, the ionic composition of atmospheric aerosols and precipitation had changed compared to previous years. In the modern period, the total amount of ions in aerosols, accounting for 0.46 ± 0.40 μg∙m−3, was lower by an order of magnitude than between 2000 and 2004. The average annual total amount of ions in precipitation in Listvyanka was almost unchanged from the average values in 2000–2010 and was 10% lower than that from 2011 to 2019 (7.3 mg/L). The ratio of major ions of sulphates and ammonium changed in the aerosol composition: compared to the period from 2000 to 2004, in 2020, the contribution of ammonium ions had decreased significantly, from 32% to 24%; the contribution of sulphates had increased to 43%, and the contribution of calcium had increased from 8 to 13%. Since 2010, the contribution of K+ ions has increased to 8–10%, indicating the effect of smoke aerosols from wildfires. In precipitation, despite the dominance of sulphates (26%) and calcium (18%) throughout the year, the contribution of nitrates increases to 19% during the cold season (from October to March), while the contribution of ammonium ions and hydrogen ions increases to 13% and 17%, respectively, in the warm season (from April to September). In 2020, as in previous research years, the acidity of precipitation at the Listvyanka station was elevated (pH 5.1 ± 0.5); 50% of precipitation in 2020 had pH ˂ 5. We quantified ions in atmospheric aerosols and precipitation on the underlying surface of the coastal southwestern part of Lake Baikal. Ion fluxes with precipitation were the highest in the warm season, which corresponds to the annual maximum precipitation. Unlike previous years (from 2000 to 2010 and from 2011 to 2019), wet deposition of most ions—especially calcium, ammonium and nitrates—had decreased in 2020. There was a 35-fold decrease in nitrogen fluxes and a 5-fold decrease in sulphur fluxes in aerosols, as well as 1.6-fold and 1.3-fold decreases, respectively, in precipitation.

Geochemical characteristics and potential biogeochemical effect of water-soluble ions in atmospheric aerosols over the western boundary regions of Pacific Ocean

Atmospheric aerosol samples over the western boundary regions of Pacific Ocean were collected during August 2014–October 2014 and November 2015–February 2016 on R/V Ke Xue, and concentrations of major water-soluble ions, NO3−, NO2−, NH4+, PO43−, SO42−, MSA−, Cl−, and Na+, were determined to study their seasonal distributions, sources and biogeochemical effect. The results showed that the average concentrations of NO3−, Cl− and Na+ were higher in winter, while the other ions had higher concentrations in summer. Most water-soluble ions presented obvious high-value centers in nearshore, indicating the significant influence of terrestrial input. Terrestrial input and marine emission were two major factors causing variation in concentrations of water-soluble ions, although their relative contributions were different in summer and winter. The average MSA/nss-SO42− ratios in summer and in winter were 1.60% and 2.10%, respectively, based on which the contributions of anthropogenic sources to the total SO42− were calculated to be 45.7% and 30.1% in summer and winter, respectively. Yet the contribution of biogenic sources to the total SO42−, which was 14.9% in summer and 14.4% in winter, showed no seasonal change. Apart from air masses from Asian continent, air masses from Japan as well as from Indonesia were also important terrestrial sources of aerosol ions according to air mass backward trajectories analysis. Based on the distribution patterns of aerosol ions, the studied area was divided into Southeast China coastal sea area and Western Pacific open sea area, and the dry deposition fluxes of DIN for these two areas were 6166 μg m−2 day−1 and 574 μg m−2 day−1, which could support 5.6–19.4% and ~13.8% of the new production in the East China Sea and the Western Pacific, respectively. Therefore, atmospheric aerosols as an important medium for transporting nutrients to the study area should attract much attention.

Mass Concentrations and Size Distributions of Water-soluble Inorganic Ions in Atmospheric Aerosols in Beibei District, Chongqing

In order to study the concentration and distribution characteristics of water-soluble inorganic ions in aerosol particles of the Beibei district of Chongqing, aerosol samples were collected with an Andersen cascade impactor between March 2014 and February 2015. Water-soluble inorganic ions, including Na+, NH4+, K+, Mg2+, Ca2+, F-, Cl-, NO3-, and SO42- were determined for different particle sizes (9.00, 5.80, 4.70, 3.30, 2.10, 1.10, 0.65, and 0.43 μm) using the ion chromatography method. Results showed that SO42-, NH4+, NO3-, Cl-, Na+, and K+ were mainly distributed in fine particles, while Mg2+, Ca2+, and F- were mainly present in coarse particles. SNA (SO42-, NH4+, and NO3-) exhibited clear unimodal distribution, with peaks in the droplet mode of 0.65-1.10 μm, mainly present in the form of (NH4)2SO4 and NH4NO3 in fine particles. The formation of SO42- is mainly attributed to in-cloud processes and partly to oxidation of SO2. Na+, Cl-, and Mg2+ exhibited bimodal distribution in coarse and fine particles; K+ was a single peak distribution in the range of 0.43-1.10 μm, while peaks of F- and Ca2+ concentrations were in coarse particles. Average annual concentrations of total water-soluble ions in PM2.1 and PM9.0 were (32.68±15.28) μg·m-3and (48.01±19.66) μg·m-3 over the observation period. Seasonal variations of PM2.1 and PM9.0concentrations decreased in the order of winter > spring > summer > autumn. This was the same for most ions, but a small number of ions (F-, Mg2+ and Ca2+) had a different pattern in the spring, summer, and winter. The SNA were the major components of water-soluble ions in PM2.1, and Ca2+ was the major component of water-soluble ions in PM9.0 besides SNA. The concentration of cations was significantly higher than that of anions' in PM2.1 and PM9.0, with a certain correlation between different ions. Emissions from motor vehicle exhaust, combustion processes, soil sources, and fugitive dust were the major sources of water-soluble ions in this area. The effect of air temperature on secondary ions is significant (P<0.05), but relative humidity and wind speed have no significant effect (P>0.05).

Size Distributions of Water-soluble Inorganic Ions in Atmospheric Aerosols during the Meiyu Period on the North Shore of Taihu Lake, China

In order to research the impact on air pollution from Meiyu (a special period of seasonal heavy rainfall between late May and June in the middle-lower Yangtze area in China (Qian et al., 2009)), the pollutant gas concentrations, size distributions, and water-soluble inorganic ions of aerosols were measured on the north shore of Taihu Lake from June 10 to June 26, 2014. Results show that the PM1.1 (aerodynamic diameter ≤ 1.1 µm) grew in particle size, becoming PM1.1-2.1 (1.1 µm ≤ aerodynamic diameter ≤ 2.1 µm) and then CPM (coarse particle matter; aerodynamic diameter > 2.1 µg) due to coagulation growth and chemical reactions, prior to Meiyu. The ions, anions, and cations all exhibited bimodal distributions before Meiyu, with peak positions of 0.43–1.1 and 9–10 µm, and trimodal distributions during Meiyu, with unfixed peak positions. The spectral size distributions of the SO42–, NO3–, and NH4+ were all bimodal or trimodal before Meiyu, and SNA (SO42–, NO3–, and NH4+) was the main component of the PM1.1 and PM1.1-2.1. Vehicle emissions were more important and the secondary formation of SO42– from SO2 occurred more readily during Meiyu than before Meiyu. The nitrogen oxidation ratio (NOR) was lower than the sulfur oxidation ratio (SOR), and the secondary formation of NO3– from NOx infrequently occurred in Wuxi compared to that of SO42– from SO2. The samples collected during the pre-Meiyu season and Meiyu all fell below the line 1:1 (CE:AE) (cation equivalence:anion equivalence), suggesting that the volatilization of ammonium and nitrate as well as unmeasured hydrogen ions may have caused the loss of cations, which resulted in insufficient cations for neutralizing the anions and subsequently, acidic properties for the aerosol. [NH4+ + Ca2+] are evidently sufficient for neutralizing [SO42– + NO3– + NO2– + Cl–].

Characteristics of Water-soluble Inorganic Ions in Atmospheric Aerosols in Shenyang

To investigate the levels and seasonal variation of water soluble inorganic components in ambient aerosol in Shenyang, 25 samples were collected with Andersen cascade sampler from Jun. 2012 to May. 2013 and nine water-soluble ions in samples were analyzed by IC. The different characteristics of aerosols between clean and pollution days in winter were discussed based on these samples. The results showed that the annual concentrations of total water soluble inorganic ions were 22.30 μg·m^-3 and 14.29 μg·m^-3 in fine and coarse particles, and SO4^2- and Ca²⁺ were the most abundant ions, respectively. The ratio of mass concentration between SO4^2- and NO3^- was 2.28 and the NH4⁺ existed in the form of (NH4)2SO4 and NH4NO3 in fine particles. The concentrations of total water soluble ions in fine particles were higher in winter and spring compared with those in summer and autumn, and they varied significantly between different seasons. The fossil fuel consumption led to the maximum values of secondary inorganic ions in fine particles during winter. The concentrations of total water soluble ions in coarse particles varied slightly though they were higher in autumn and lower in winter, and the wind-drifting sand was responsible for the higher concentration of Ca²⁺ in autumn in coarse particles. The concentration of SO4^2-, NO3^-, NH4⁺ accounted for 80% of total water soluble inorganic ions during clean days and rose to 94% during pollution days. The ions were mostly concentrated in the size ranges of 0.43-0.65 μm and 0.43-2.1 μm respectively during clean and pollution days in fine mode. The peaks of SO4^2-, NO3^-, NH4⁺ in fine mode shifted from 0.43-0.65 μm to 1.1-2.1 μm, which meant these ions were transformed from condensing mode to droplets mode during pollution days. The air mass produced at Lake Baikal and transported through high altitude to the sampling point caused clean days, however the air mass transported through industrial areas might bring pollutions to the sampling point then caused pollution days.

Water-soluble ions in atmospheric aerosols measured in five sites in the Yangtze River Delta, China: Size-fractionated, seasonal variations and sources

Abstract In order to investigate the regional variations of water-soluble ions (WSIs), size-resolved measurement of aerosol particles and WSIs was conducted by using Anderson Sampler and Ion Chromatography at five sites (Nanjing, Suzhou, Lin'an, Hangzhou and Ningbo) in the Yangtze River Delta (YRD) region, China in the Autumn of 2012 and Winter, Spring and Summer of 2013. WSIs exhibited obvious seasonal variations due to the monsoon conversion, with the highest level in winter and lowest level in summer. The aerosol mass concentrations and WSIs in different size segments varied with four seasons. The dominant ions concentrations in PM2.1 ranked in the order of SO 4 2 − > NO 3 − > NH 4 + > Cl− > K+ > Ca2+, and the dominant ions concentrations in PM2.1–10 ranked in the order of Ca2+ > NO 3 − > SO 4 2 − > Cl− > NH 4 + > Na+. The size spectra of mass and WSIs concentration peaked mostly at 0.43–0.65 μm in four seasons. The concentration discrepancies of WSIs in different cities were caused by the geographic locations and emission source. It's belonged to ammonium-rich distribution in PM2.1 and ammonium-poor distribution in PM2.1–10 in the YRD region. The impact of temperature on mass concentrations of NO 3 − and NH 4 + in PM2.1 were stronger than those in PM2.1−10. PCA analysis shows that the sources of WSIs dominant by anthropogenic sources, soil particles or falling dust, sea salt and burning process.

Seasonal variations and size distributions of water-soluble ions in atmospheric aerosols in Beijing, 2012

The characteristics of water-soluble ions in airborne particulate matter in Beijing were investigated using ion chromatography. The results showed that the total concentrations of ions were 83.7±48.9μg/m3 in spring, 54.0±17.0μg/m3 in summer, 54.1±42.9μg/m3 in autumn, and 88.8±47.7μg/m3 in winter, respectively. Furthermore, out of all the ions, NO3−, SO42− and NH4+ accounted for 81.2% in spring, 78.5% in summer, 74.6% in autumn, and 76.3% in winter. Mg2+ and Ca2+ were mainly associated with coarse particles, with a peak that ranged from 5.8 to 9.0μm. Na+, NH4+ and Cl− had a multi-mode distribution with peaks that ranged from 0.43 to 1.1μm and 4.7 to 9.0μm. K+, NO3−, and SO42− were mainly associated with fine particles, with a peak that ranged from 0.65 to 2.1μm. The concentrations of Na+, K+, Mg2+, Ca2+, NH4+, Cl−, NO3− and SO42− were 2.69, 2.32, 1.01, 4.84, 16.9, 11.8, 42.0, and 44.1μg/m3 in particulate matter (PM) on foggy days, respectively, which were 1.4 to 7.3 times higher than those on clear days. The concentrations of these ions were 2.40, 1.66, 0.92, 4.95, 17.5, 7.00, 32.6, and 34.7μg/m3 in PM on hazy days, respectively, which were 1.2–5.7 times higher than those on clear days.

Water-soluble ions in atmospheric aerosols measured in Xi'an, China: Seasonal variations and sources

Daily PM 2.5 and water-soluble inorganic ions (Na +, NH 4 +, K +, Mg 2+, Ca 2+, Cl −, NO 3 − and SO 4 2−) were collected in Xi'an (34.23°N, 108.88°E), China from March 2006 to March 2007. PM 2.5 was collected using battery-powered mini-volume samplers. And the ions were determined by ion chromatography from the measured aerosol mass. The annual average mass concentration of PM 2.5 was found to be 194.1 ± 78.6 μg m − 3 , which exceeded substantially the international guidelines for health concerns. The seasonal average mass concentration of PM 2.5 was highest in winter (266.8 μg m − 3 ) and lowest in summer (138.6 μg m − 3 ). The three highest abundant ions were SO 4 2−, NO 3 −, and NH 4 +, with average concentrations of 35.6 ± 19.5 μg m − 3 , 16.4 ± 10.1 μg m − 3 , and 11.4 ± 6.8 μg m − 3 , which were accounted for 18.7%, 8.0%, and 5.7% of the PM 2.5 mass, respectively. The major ions were in the species of (NH 4) 2SO 4, NH 4HSO 4 and NH 4NO 3, and their concentrations were highest in winter, due to high coal combustion. The concentrations of Ca 2+ were higher in spring than other seasons, due to the higher mineral dust concentrations. Ca 2+ was strongly correlated with CO 3 2−, which was calculated as the difference in the measured cations minus anions. Ion balance calculations indicate that the PM 2.5 was acidic, and this result is consistent with the measurement of pH values. Sulfur oxidation ratio was higher in summer and autumn, which implies that the formation of secondary sulfate-rich particles is favored by warm and relatively moist weather. Nitrogen oxidation ratio was highest in autumn.

Size distributions of dicarboxylic acids and inorganic ions in atmospheric aerosols collected during polar sunrise in the Canadian high Arctic

Size‐segregated atmospheric aerosols (11 stages separating particles from &lt;0.04 to &gt;14.2 μm) collected in the Arctic during the polar sunrise at Alert were analyzed for aerosol mass, dicarboxylic acids, and major inorganic ions. Oxalic, malonic, succinic, and glutaric acids were detected in all size ranges, with oxalic acid being dominant. Their concentrations maximized in the accumulation mode either at 0.24–0.40 or 0.40–0.8 μm aerodynamic diameters, suggesting that diacids were mainly formed by gas‐to‐particle conversion via photochemical oxidation of nonmethane hydrocarbons and oxygenated organics originated from continental pollution sources. The relative abundances of oxalic acid were higher in the 0.24‐ to 0.4‐μm size particles (73–78%) than in supermicrometer particles (40–60%), indicating that oxalic acid is produced by gas phase oxidation of precursors followed by accumulation on preexisting particles. Mass size distributions of NH4+ and SO42− peaked in the accumulation mode similar to those of small diacids. The sea‐salt enrichment factor of K+ (biomass burning tracer) relative to Na+ maximized in 0.1‐ to 0.8‐μm sizes, whereas those of Mg2+ and Ca2+ (dust tracers) in 0.4‐ to 7.8‐μm particles. Maximized chlorine loss and bromine enrichment were found at 0.4–0.8 and 0.24–0.4 μm sizes, respectively. Concentrations of Br−, which typically showed a submicrometer maximum, increased significantly during an O3 depletion event having a shift of size distribution to a supermicrometer mode. During this event, oxalic acid concentration relative to succinic acid increased in submicrometer mode (0.24–0.4 μm), adding to a growing body of evidence supporting the hypothesis that halogen chemistry is important in the production and loss of oxalic acid in the arctic atmosphere.

Coarse–fine and day–night differences of water-soluble ions in atmospheric aerosols collected in Christchurch and Auckland, New Zealand

The water-soluble ions in fine (PM <2.5) and coarse (PM 2.5−10) atmospheric aerosols collected in Christchurch during winter 2001, spring 2000 and summer 2001, and in Auckland during winter 2001 have been studied in terms of coarse–fine and day–night differences. Although the chemical characteristics of the coarse particles were similar in both cities, those of the fine particles collected in the Christchurch winter were significantly different, as manifested by higher concentrations of nss-K +, nss-Cl −, nss-Ca 2+, nss-SO 4 2−, NO 3 − and NH 4 +. It was found that nighttime PM 10 and nss-K + concentrations were much higher than their daytime concentrations in the Christchurch winter but a clear day–night difference was not apparent in the Auckland winter. Moreover, in the winter, sea-salt ions did not show a day–night difference; however, nss-SO 4 2− had opposite day–night variation in the two cities. An ion balance calculation has shown that in most samples, coarse particles can be neutral or alkaline, however, fine particles can be neutral or acidic. The possibility of ammonium salts existing in the fine particles collected in the Christchurch winter is discussed and it is concluded that a variety of ammonium salts were present. Equivalent ratios suggest that the fine particles may be significantly aged in the Christchurch winter. The evidence from our soluble ion study strongly suggests that wood and coal burning and secondary aerosols make a significant contribution to fine particulate mass in the Christchurch atmosphere. Thus, home-heating, a sheltered geographic location and relatively calm atmospheric condition are thought to be the major causes for the serious atmospheric particulate pollution in the Christchurch winter.

Size distribution of ions in atmospheric aerosols

The aim of this paper is to present data about the concentration and size distribution of ions in atmospheric aerosol under slightly polluted urban conditions in Hungary. Concentration of inorganic cations (ammonium, sodium, potassium, calcium, magnesium), inorganic anions (sulfate, nitrate, chloride, carbonate) and organic acids (oxalic, malonic, succinic, formic and acetic acid) for 8 particle size range between 0.0625 and 16 μm were determined. As was the case for ammonium, sulfate and nitrate, the organic acids were mostly found in the fine particle size range. Potassium and chloride were rather uniformly distributed between fine and coarse particles. Sodium, calcium, magnesium and carbonate were practically observed in the coarse mode. The results obtained for the summer and the winter half-year were also compared. The mass concentrations were recalculated in equivalents, and the ion balance was found to be reasonable in most cases. Measurement of the pH of the aerosol extracts indicates that the aerosol is acidic in the fine mode, but alkaline in the coarse particle size range.