Characteristics Of Water-soluble Ions Research Articles

Characteristics of Water-soluble Ions in an Autumn Haze Process in the Southern Sichuan Urban Agglomeration After the Implementation of China's Air Pollution Prevention and Control Action Plan

To investigate the PM2.5 pollution in the southern Sichuan urban agglomeration after the implementation of China's Air Pollution Prevention and Control Action Plan (APPCAP), PM2.5 samples were simultaneously collected in four cities (Neijiang, Zigong, Yibin, and Luzhou) from November 7 to 19, 2018. The pollution characteristics of PM2.5 and main water-soluble ions were analyzed in combination with the synoptic situation, and the influence of regional transport on atmospheric pollution was also discussed in this study. The results showed that the mean ρ(PM2.5) in this region was (67.2±38.3) μg·m-3, being highest in Luzhou and lowest in Neijiang. The proportion of SNA (SO42-, NO3-, and NH4+) in PM2.5 was 33.3%, among which NO3- was dominant. From the intermediate stage (2015) to the end(2018) of the implementation of APPCAP, ρ(PM2.5) values were increased by 13.8%, 47.2%, and 69.1% in Neijiang, Yibin, and Luzhou, respectively, though unchanged in Zigong. Due to the significant reduction in ρ(SO2) but slight decrease or increase in ρ(NO2), as well as the lack of controlling NH3 emissions, from 2015 to 2018, ρ(NO3-) had increased by 36.7%-116.0%, whereas ρ(SO42-) decreased by 19.8%-40.2%, and ρ(NH4+) changed slightly in four cities. On haze days, the nitrogen oxidation rate (NOR) increased by 60.0%-118.2%, whereas the sulfur oxidation rate (SOR) increased slightly or decreased, leading to a significant increase in ρ(NO3-) (2.7-3.0 times that on clean days) and NO3-/SO42- mass ratios (1.7-1.9 on haze days). These values indicated that the secondary formation of nitrate was the dominant chemical mechanism in this haze process. On haze days, the PM2.5 pollution in this region was mainly affected by the regional transport within Sichuan Basin, particularly by the northeasterly air masses passing through Chongqing.

The seasonal characterization and source analysis of water-soluble inorganic ions in PM2.5 in Fuxin, northeast China

In Fuxin, a few existing studies have illustrated the pollution characteristics of water-soluble ions (WSIIs) in PM2.5 in four seasons. To track the particulate pollution in Fuxin, sample filters of PM2.5 in the four seasons of spring, summer, autumn and winter in 2019 were collected. For the first time, the concentration and seasonal variation characteristics of PM2.5 and WSIIs were tested by gravimeter method and ion chromatography. Characteristics of WSIIs and their existence sources and forms were explored by ion balance calculation, correlation analysis and principal component analysis. The annual average concentrations of PM2.5 and WSIIs were (33.23 ± 13.03) μg·m−3 and (22.86 ± 9.62) μg·m−3, respectively. The seasonal WSIIs concentration followed the order: spring (29.98 μg·m−3) > autumn (28.85 μg·m−3) > winter (21.32 μg·m−3) > summer (11.28 μg·m−3). In WSIIs, 81.41% of them were secondary inorganic ions (SO4 2−, NO3 −, and NH4 +), contributed about 68.80% to PM2.5, and the chemical forms were mainly (NH4)2SO4 and NH4NO3. In this study, it has been revealed that PM2.5 samples exhibited acid properties in spring and autumn while, displayed alkalinity in summer and winter. The average value of NO3 −/SO4 2− was 0.67, so from these data it can be illustrated that fixed pollution sources were found to be dominant over mobile sources in Fuxin. The main identified sources of WSIIs in four seasons in Fuxin were sea salt particles and secondary particles, respectively. These results showed that the geographical factors of Bohai Bay and secondary transformation had a significant impact on the concentration of WSIIs of PM2.5 in Fuxin.

Characteristics of water-soluble ions in condensable particulate matter emitted from stationary sources in Wuhan

This study investigated the concentration and characterization of condensable particulate matter (CPM) and filterable particulate matter (FPM) emitted from different stationary sources in Wuhan. The concentrations of FPM and CPM were measured based on USEPA Method 202 and the water-soluble ions in particulate matter were analyzed using ion chromatography. The micro-morphological characteristics of the CPM were detected with scanning electron microscopy (SEM) techniques. The CPM concentrations for coal-fired plant A (Stack#1), coal-fired plant B (Stack#2), sintering plant (Stack#3), incineration plant (Stack#4), cement plant (Stack#5), glass plant (Stack#6) and biomass combustion plant (Stack#7) were 20.30 ± 1.51, 26.00 ± 1.53, 28.68 ± 1.15, 6.82 ± 0.55, 5.41 ± 1.59, 8.49 ± 0.76 and 25.50 ± 1.50 mg/Nm3, which were much higher than the corresponding FPM values except for Stack#3. These results indicate that different types of stationary sources in Wuhan do emit some CPMs. The CPMs collected from wet flue gas desulfurization (WFGD) plants were much higher than semi-dry flue gas desulfurization (SDFGD) plants. Moreover, SO42−, Cl−, NH4+ and NO3− were the major water-soluble ions in the CPM, which accounted for more than 90% of the total ions. These major ions could be mainly transformed from their gaseous precursors of SOX, HCl, NH3 and NOX, respectively. Na+ was more likely to form solid particles and was collected in the CPM filter, while SO42− was more likely to be collected in the impringer in the form of dissolved particulate matter.

The pollution characteristics and source analysis of water-soluble ions in indoor PM2.5 during the Spring Festival in Jingyue Suburb of Changchun City

The characteristics of water-soluble ions in indoor PM2.5 during the Spring Festival in Changchun City were analyzed by ion chromatography. The results showed that the main water-soluble ionic components in the indoor and non-combustion periods were SO4 2- and Ca2+, and the concentration of Na+, K+, Mg2+, F-, Cl- and NO3 - increased in the fireworks and firecrackers, among which Cl- and NO3 -. The concentration increased significantly compared with the non-combustion period, and peaked with PM2.5 concentration in the first month of the first month and the first month of the first month; the correlation between NH4 + and SO4 2- during the discharge and non-combustion periods was greater than the correlation between NH4 + and NO3 -, NH4 + Sulfate is preferentially combined with SO4 2-, and secondary ions are mainly in the form of (NH4)2SO4 and NH4NO3. Cluster analysis and correlation analysis indicate that the sources of water-soluble ions in indoor PM2.5 during the Spring Festival can be classified into four categories. Biomass combustion source, automobile exhaust gas source, coal-fired emission source and soil dust, among which the main sources of Na+, K+, Mg2+, Cl-, SO4 2- during the discharge period are the fireworks and firecrackers.

Distribution Characteristics of Water Soluble Ions Under Different Weather Conditions During the Youth Olympic Games in Nanjing

To study the variation characteristics of water soluble ions during youth Olympic Games, PM2.5 and water soluble ions were observed by using the beta dust instrument, Anderson 9th sampler and IC type ion chromatography analyzer from August 6 to September 4, 2014. The observations were divided into three types of weather, sunny, rainy and cloudy. The average concentrations of PM2.5 under different weather conditions were sunny > cloudy > rainy days. The concentrations of water soluble ions in PM1.1, PM1.1-2.1 and PM2.1-10 were also sunny > cloudy > rainy days, and the obliterate of fine particles by precipitation process was more obvious. The spectra of Ca2+ and Mg2+ were bimodal. The scavenging effects of SO42- and NH4+ in range of 0.65-1.1 μm were stronger. The ratio of NO3-/SO42- under different weather conditions was less than 1, and the ratio of NO3-/SO42- in rainy and cloudy days was higher than that in sunny days. The values of SOR and NOR in the three kinds of weather conditions were more than 0.1, SO2 and NO2 had different degrees of transformation, there was more secondary pollutant in the atmosphere.

Size-resolved aerosol water-soluble ions at a regional background station of Beijing, Tianjin, and Hebei, North China

The characteristics of water-soluble ions in size-resolved particulate matter were investigated using ion chromatography at Shangdianzi, a regional background station of Beijing, Tianjin, and Hebei. Seasonal total concentrations of ions (Na+, Mg2+, K+, Ca2+, NH4+, Cl−, SO42− and NO3−) were 75.5±52.9μg/m3 in spring, 26.5±12.3μg/m3 in summer, 22.7±20.4μg/m3 in autumn, and 31.1±23.9μg/m3 in winter, respectively. The secondary ions (NO3−, SO42− and NH4+), mainly associated with fine particles, accounted for 84.2% in spring, 82.1% in summer, 81.5% in autumn and 76.3% in winter of all ions. Strong correlations were found between NH4+ and SO42− (r=0.95, p<0.01) as well as NH4+ and NO3− (r=0.90, p<0.01) in fine particles; while in coarse particles, correlations between Mg2+ and NO3− (r=0.80, p<0.01), and Ca2+ and NO3− (r=0.85, p<0.01) were found. The concentrations of Na+, K+, Mg2+, Ca2+, NH4+, Cl−, NO3−, and SO42− were 2.02, 0.81, 0.36, 1.65, 9.58, 4.01, 18.9, and 18.4μg/m3 in particulate matter from southeast-derived air masses, which were typically 1.58–3.37 times higher than in northwest trajectories. Thus, concentrations of water-soluble ions at this background station were heavily influenced by regional transport of serious pollution derived from biomass burning, coal combustion, industrial and vehicle exhaust emissions from Beijing, Tianjin, and Hebei.

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.

Characteristics of water-soluble ions and carbon in fine and coarse particles collected near an open burning site

Abstract This study investigates the chemical characteristics of particles that were collected from the open burning of wax apple agricultural waste, and evaluates the impact of such burning on regional air quality. The water-soluble ions, elemental carbon (EC), and organic carbon (OC) in fine (Dp ≤ 2.5 μm) and coarse (2.5 ( NH 4 + , NO 3 − and SO 4 2 − ) decreased. The Na+/Cl− molar ratios of fine particles before, after, and during the open burning 0.40, 0.18, and 0.24, respectively; however, the corresponding (Na+ + K+)/Cl− molar ratios were 0.74, 0.99, and 0.39, respectively. OC, K+ and Cl− were quite abundant in the open burning of agricultural waste (wax apple), and the OC/Na+, K+/Na+, and Cl−/Na+ (mass) ratios in fine particles (318, 10.2, and 10.5, respectively) may be used as reference indexes associated with the open burning of wax apple waste.

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

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.

천안시 대기 입자 중 수용성 이온성분의 계절적 특성 및 요인분석을 통한 오염기여도 평가

천안시 대기 입자 중 수용성 이온성분의 특성을 분석한 결과, 양이온은 <TEX>$Na^+$</TEX>과 <TEX>$NH_4^+$</TEX>이, 음이온은 <TEX>$NO_3^-$</TEX>와 <TEX>$SO_4^{2-}$</TEX>이 조대입자와 미세입자에서 모두 주요한 이온성분으로 조사되었다. 분석된 수용성 이온성분의 농도는 미세입자가 조대입자보다 높은 농도로 나타났으며, 겨울과 봄철에 높은 농도를, 여름철에 가장 낮은 농도를 나타냈다. 총 수용성 이온 성분은 전체 입자의 질량 중 조대입자에서는 계절별로 봄 24.4%, 여름 33.2%, 가을 40.7%, 겨울 39.6%를, 미세입자에서는 각각 43.0%, 59.7%, 55.4%, 53.2%를 차지하는 것으로 분석되어, 조대입자 보다는 미세입자에서 차지하는 비율이 컸으며, 다른 계절보다는 봄철에 낮은 비율을 나타냈다. 이들 수용성 이온성분의 요인분석을 수행한 결과 조대입자는 2개의 요인이, 미세입자는 4개의 요인이 추출되었다. 이로부터 조대입자의 경우 자연적 배출원으로 부터의 기여가 70.03%로, 미세입자의 경우 인위적 배출원으로 부터의 기여가 66.01%로 추정되었다. Seasonal characteristics of water soluble ions in atmospheric particles in Cheonan were studied between 2008 and 2009. <TEX>$Na^+$</TEX>, <TEX>$NH_4^+$</TEX> and <TEX>$NO_3^-$</TEX>, <TEX>$SO_4^{2-}$</TEX> were the principle cations and anions in both coarse and fine particles. Water soluble ions occupied 24.4%(spring), 33.2%(summer), 40.7%(fall), and 39.6%(winter) of the total mass of coarse particles. In fine particles, 43.0%(spring), 59.7%(summer), 55.4%(fall), and 53.2%(winter) of mass were occupied by water soluble ions. From the factor analysis, 2 and 4 factors were extracted for water soluble ions in coarse and fine particles, respectively. 70.33% of water ions in the coarse particles were estimated from the natural source, but 66.01% in the fine particles were from the anthropogenic source.