Water-soluble Ions In PM2 Research Articles

Comparison of Bacterial Community Structure in PM2.5 within Broiler Houses under Different Rearing Systems in China

Background: In intensive poultry farming, high concentrations of indoor particulate matter (PM) impact production performance and welfare. In this study, PM2.5 level and bacterial community diversity were investigated in a multilayer cage house rearing system (CH) and a net flooring house rearing system (FH) during different growth stages to clarify the effects of the rearing systems on the diversity of airborne bacteria and help improve health management. Methods: The IC and high-throughput sequencing were used for ion composition and bacterial diversity analysis of PM2.5 collected from CH and FH. Results: The concentrations of NH3, CO2 and PM2.5 in CH were significantly lower than FH (p < 0.001) in both middle and late rearing stages. PM concentrations gradually increased with broiler growth only in FH. The water-soluble ions of PM2.5 samples had no significant difference between the two systems (p > 0.05). Firmicutes, Actinobacteria and Proteobacteria were the most abundant phyla in both the atmosphere and the broiler houses, but the composition was significantly different. The bacterial community in the broiler houses had strong correlations with temperature, humidity and PM of extremely high concentrations. Ions had stronger correlations with microbial community structure. Conclusions: The superiority of CH in environmental control over FH indicates that improved techniques in environmental control and breeding management can greatly reduce farming air pollution and improve the health management of broiler houses.

Characteristics of Particulate Matter at Different Pollution Levels in Chengdu, Southwest of China

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.

Emission characteristics of water-soluble ions in PM2.5 released by forest fuel combustion in Great Xing'an Mountains, Inner Mongolia, China.

Understanding the emission factors of fine particulate matter (PM2.5) released by forest fuel combustion is important for revealing the impacts of forest fire on atmosphere and ecosystem. Water-soluble ions are important components of fine particulate matter, with great significance to the formation of particulate matter. A self-designed biomass combustion system was used to simulate the combustion of three components (trunks, branches, barks) and their surface dead fuel (litter, semi-humus, humus) of five tree species (Quercus mongolica, Betula platyphylla, Larix gmelinii, Betula dahurica, Populus davidiana) and branches of three shrub species (Corylus heterophylla, Lespedeza bicolor, Rhododendron dauricum) in Great Xing'an Mountains in Inner Mongolia. The water-soluble ion emission factors (Na+, NH4+, K+, Mg2+, Ca2+, F-, Cl-, NO3-, NO2-, SO42-) in PM2.5 under two combustion conditions (smoldering and flaming) were measured by ISC1100 ion chromatograph. The results showed that for the water-soluble ion detected in PM2.5 from combustion of all types of materials, K+, Cl- and Na+ were the main components in smoldering, while K+, Cl- and SO42- were the main components in flaming. There was significant difference in the total amount of water-soluble ions in PM2.5 from the same type of material under different combustion conditions. During the smoldering period, the emission factor of water-soluble inorganic ions in PM2.5 of shrub branches was higher than that of flaming. The cation to anion ratio in PM2.5 was 1.26 for all trees, 1.12 for surface dead fuel of trees, and 2.0 for branch of shrub, indicating that the particulate matter was alkaline. Forest fires in Great Xing'an Mountains could not result in ecosystem acidification by releasing water-soluble ions.

Effect of Different Pollution Parameters and Chemical Components of PM2.5 on Health of Residents of Xinxiang City, China.

The present study was planned to explore the pollution characteristics, health risks, and influence of atmospheric fine particulate matter (PM2.5) and its components on blood routine parameters in a typical industrial city (Xinxiang City) in China. In this study, 102 effective samples 28 (April–May), 19 (July–August), 27 (September–October), 28 (December–January) of PM2.5 were collected during different seasons from 2017 to 2018. The water-soluble ions and metal elements in PM2.5 were analyzed via ion chromatography and inductively coupled plasma–mass spectrometry. The blood routine physical examination parameters under different polluted weather conditions from January to December 2017 and 2018, the corresponding PM2.5 concentration, temperature, and relative humidity during the same period were collected from Second People’s Hospital of Xinxiang during 2017–2018. Risk assessment was carried out using the generalized additive time series model (GAM). It was used to analyze the influence of PM2.5 concentration and its components on blood routine indicators of the physical examination population. The “mgcv” package in R.3.5.3 statistical software was used for modeling and analysis and used to perform nonparametric smoothing on meteorological indicators such as temperature and humidity. When Akaike’s information criterion (AIC) value is the smallest, the goodness of fit of the model is the highest. Additionally, the US EPA exposure model was used to evaluate the health risks caused by different heavy metals in PM2.5 to the human body through the respiratory pathway, including carcinogenic risk and non-carcinogenic risk. The result showed that the air particulate matter and its chemical components in Xinxiang City were higher in winter as compared to other seasons with an overall trend of winter > spring > autumn > summer. The content of nitrate (NO3−) and sulfate (SO42−) ions in the atmosphere were higher in winter, which, together with ammonium, constitute the main components of water-soluble ions in PM2.5 in Xinxiang City. Source analysis reported that mobile pollution sources (coal combustion emissions, automobile exhaust emissions, and industrial emissions) in Xinxiang City during the winter season contributed more to atmospheric pollution as compared to fixed sources. The results of the risk assessment showed that the non-carcinogenic health risk of heavy metals in fine particulate matter is acceptable to the human body, while among the carcinogenic elements, the order of lifetime carcinogenic risk is arsenic (As) > chromium(Cr) > cadmium (Cd) > cobalt(Co) > nickel (Ni). During periods of haze pollution, the exposure concentration of PM2.5 has a certain lag effect on blood routine parameters. On the day when haze pollution occurs, when the daily average concentration of PM2.5 rises by 10 μg·m−3, hemoglobin (HGB) and platelet count (PLT) increase, respectively, by 9.923% (95% CI, 8.741–11.264) and 0.068% (95% CI, 0.067–0.069). GAM model analysis predicted the maximum effect of PM2.5 exposure concentration on red blood cell count (RBC) and PLT was reached when the hysteresis accumulates for 1d (Lag0). The maximum effect of exposure concentration ofPM2.5 on MONO is reached when the lag accumulation is 3d (Lag2). When the hysteresis accumulates for 6d (Lag5), the exposure concentration of PM2.5 has the greatest effect on HGB. The maximum cumulative effect of PM2.5 on neutrophil count (NEUT) and lymphocyte (LMY) was strongest when the lag was 2d (Lag1). During periods of moderate to severe pollution, the concentration of water-soluble ions and heavy metal elements in PM2.5 increases significantly and has a significant correlation with some blood routine indicators.

Seasonal and areal variability in PM2.5 poses differential degranulation and pro-inflammatory effects on RBL-2H3 cells

PM2.5 pollution is a widespread environmental and health problem, particularly in China. Besides leading to well-known diseases in the respiratory system, PM2.5 can also alter immune function to induce or aggravate allergic diseases. To determine whether there are temporal and spatial differences in the allergic responses to PM2.5, monthly samples were collected from four regions (urban, industrial, suburban, and rural areas) through a whole year in Nanjing city, China. Inorganic chemical components (metals and water-soluble ions) of PM2.5 were analyzed, and the rat basophil cells (RBL-2H3) exposed to PM2.5 were assessed through quantitative measures of degranulation (β-hex and histamine) and pro-inflammation cytokine (IL-4 and TNF-α) expression. The highest levels of β-hex were measured in winter and spring PM2.5 from urban and industrial areas, or autumn PM2.5 from suburban and rural areas. With respect to histamine, autumn PM2.5 samples were most potent irrespective of the location. Autumn and winter PM2.5 induced higher levels of IL-4 than spring and summer samples. However, spring and autumn PM2.5 caused higher levels of TNF-α. The concentrations of water-soluble ions (NH4+, K+ and Cl−), as well as heavy metals (Pb and Cr), were directly and statistically correlated to the inflammation observed in vitro. In general, the differences between regional and seasonal PM2.5 in stimulating cell degranulation may depend on endotoxin and airborne allergen content of PM2.5. The heavy metals and water-soluble ions in PM2.5 were mostly anthropogenic, which increased the particles' mass-based cellular inflammatory potential, therefore, their health risks, e.g. from vehicular exhaust, coal, and biomass combustion, cannot be ignored.

Low particulate nitrate in the residual layer in autumn over the North China Plain

High ozone concentrations promote the formation of nitrate in the nocturnal residual layer (RL), but this phenomenon has not been confirmed by direct observation. In this study, ozone, water-soluble ions in PM2.5 and the corresponding meteorological factors in the stable boundary layer, RL and mixing layer were observed by portable instruments carried on a tethered balloon over the North China Plain. The ozone concentration significantly increased in the RL compared to that in the stable boundary layer, while particulate nitrate significantly decreased, except in the clouds. Unfavorable environmental conditions, i.e., high temperature, low relative humidity, low aerosol surface area, and weak particle acidity, are not conducive to dinitrogen pentoxide uptake and hydrolysis to form particulate nitrate in the RL, and are conducive to the volatilization of nitrate to a gaseous state. Thus, our observations differed from traditional reports and confirmed that the morning peak of particulate nitrate at ground level is not related to the downward transport of nitrate from the RL. In addition, evidence for nitrate formation in cloudy weather is provided, and the possible impact on ozone is discussed.

Toxicological effects of personal exposure to fine particles in adult residents of Hong Kong.

Toxicological studies have demonstrated the associations between fine particle (PM2.5) components and various cytotoxic endpoints. However, few studies have investigated the toxicological effects of source-specific PM2.5 at the individual level. To investigate the potential impact of source-specific PM2.5 on cytotoxic effects, we performed repeated personal PM2.5 monitoring of 48 adult participants in Hong Kong during the winter and summer of 2014-2015. Quartz filters were analyzed for carbonaceous aerosols and water-soluble ions in PM2.5. Teflon filters were collected to determine personal PM2.5 mass and metal concentrations. The toxicological effects of personal PM2.5 exposure-including cytotoxicity, inflammatory response, and reactive oxygen species (ROS) production-were measured using A549cells invitro. Personal PM2.5 samples collected in winter were more effective than those collected in summer at inducing cytotoxicity and the expression of proinflammation cytokine IL-6. By contrast, summer personal PM2.5 samples induced high ROS production. We performed a series of statistical analyses, Spearman correlation and a source apportionment approach with a multiple linear regression (MLR) model, to explore the sources contributing most significantly to personal PM2.5 bioreactivity. Secondary inorganic species and transition metals were discovered to be weak-to-moderately associated with cytotoxicity (rs: 0.26-0.55; p<0.01) and inflammatory response (rs: 0.26-0.44; p<0.05), respectively. Carbonaceous aerosols (i.e., organic and elemental carbon; rs: 0.23-0.27; p<0.05) and crustal material (Mg and Ca) was positively associated with ROS generation. The PMF-MLR models revealed that tailpipe exhaust and secondary sulfate contributed to ROS generation, whereas secondary nitrate was the major contributor to PM2.5 cytotoxicity and inflammation. These results improve and variate the arguments for practical policies designed to mitigate the risks posed by air pollution sources and to protect public health.

Stoichiometric characteristics and economic implications of water-soluble ions in PM2.5 from a resource-dependent city

The stoichiometric characteristics of water-soluble ions (WSIs) in PM2.5, which can be used as an indicator socioeconomic development level, are mostly depending on the sources and formation mechanism of PM2.5. This work presents the stoichiometric characteristics and socioeconomic linkage of WSIs in PM2.5 from a resource-dependent city. The relationship between NO3−/SO42− and car parc indexes the contribution of mobile emission source. The equivalent ratio of WSIs suggested that aerosol particles were weak acidic due to the deficiency of cations in PM2.5, which was consistent with the average annual pH (6.27) of precipitation in Wuhai in 2015. NH4+ neutralizes PM2.5 acidity in clean and polluted days, while Ca2+ and NH4+ in dust storm days. Furthermore, the PCA analysis indicated the multi-sources pollution characteristics from Spring to Fall, which was related the small build-up area (only 62.30 km2) and the close-set of various industrial enterprises in Wuhai. The ratios of NO2/SO2 may not work effectively to identify the importance of mobile versus stationary pollution emission sources when the heavy emission from the secondary industry, especially the proportion of secondary industry higher than 65% and the ratios of NO2/SO2 lower than 0.4. This work contributes to more effective control strategies for PM2.5 in resource-dependent areas.

The characteristics and sources apportionment of water-soluble ions of PM2.5 in suburb Tangshan, China

To study characteristics and sources of water-soluble ions, the samples of PM2.5 were collected at suburb area of Tangshan. The main water-soluble ions in PM2.5 were analyzed and the source of water-soluble ions was discussed. The results showed that PM2.5 concentration was 128.45 ± 80.54 μg/m3 (winter indoor) > 112.44 ± 82.90 μg/m3 (summer indoor) > 112.44 ± 82.90 μg/m3 (winter outdoor) > 34.73 ± 31.92 μg/m3 (summer outdoor). The ion of Cl−, SO42−, NO3− and NH4+ were the main water-soluble ions in PM2.5 indoor and outdoor winter. The ion of NH4+, SO42−, NO3− and Ca2+ were the main water-soluble ions in PM2.5 indoor summer. The ion of SO42−, NO3−, NH4+ and K+ were the main water-soluble ions in PM2.5 outdoor summer. The main water-soluble ions existed in form of CaCl2, NH4NO3 and (NH4)2SO4 in winter-indoor, and in form of KCl, NH4NO3 and (NH4)2SO4 in winter-outdoor, and in form of NH4HSO4, NH4NO3 and KCl in summer-indoor, and in form of NH4HSO4, K2SO4 and NH4NO3 in summer-outdoor. Principal component analysis showed that the main source of PM2.5 in Tangshan suburb were construction dust, wind dust, stationary source and mobile source. However, the ratio for pollution sources were different for indoor and outdoor PM2.5.

Optical and chemical properties of long-range transported aerosols using satellite and ground-based observations over seoul, South Korea

Aerosols that are transported long distances to the Korean Peninsula due to seasonal weather conditions can affect the local air quality of South Korea. In general, the long-range transported aerosols are widely distributed and variable with respect to time and space. In this aspect, geostationary satellites can be used as a powerful tool for providing temporal and spatial variation of aerosols by sequentially observing a target area. In this study, select events of high-concentration aerosols transported to Seoul, the capital of South Korea, were identified and analyzed using aerosol optical properties retrieved from geostationary ocean color imager (GOCI) for the cold season (October–March) from 2015 to 2018. In addition to the satellite data, ground-based observations of particulate matter (PM) and backward trajectory models were used. Based on the trajectories of air masses simulated with the backward trajectory models, events of the long-range transported high-concentration aerosols (hereafter referred to as “LRT events”) were selected and classified into three types: yellow dust, PM traversing over the Yellow Sea (PM-YS), and PM passing through North Korea (PM-NK). Optical and chemical properties of the three LRT events were analyzed, and significantly different features were found. Yellow dust showed a relatively high mean depolarization ratio at 1020 nm (0.26), a low Ångström exponent between 440 nm and 870 nm (0.27), fine mode fraction at 500 nm (0.26), single scattering albedo at 440 nm (0.93), and lidar ratio at 675 nm (37 sr) compared with those during the other PM events. Moreover, the proportions of Ca+ concentrations to the water-soluble ions in PM2.5 and concentrations of Ca and Fe among inorganic elements in PM2.5 significantly increased during the yellow dust event. On the contrary, the PM events (PM-YS and PM-NK) had relatively high mean Ångström exponent (1.28 and 1.38), fine mode fraction (0.94 and 0.81), single scattering albedo (0.96 and 0.94), lidar ratio (66 sr and 44 sr), and low depolarization ratios (0.035 and 0.066). The ratios of NO3− and SO42− to water-soluble ions in PM2.5 were significantly increased during the high PM events. By comparing the two PM events, the volume median radius of fine mode particles and fine mode fraction of PM-YS were found to be considerably higher compared with those of PM-NK. Such different characteristics found in this study for the three LRT events indicate that optical and chemical analyses of aerosols using satellite and ground-based observations can give us the possibility of roughly identifying aerosol types (yellow dust or PM) and trajectories (passing through the Yellow Sea or North Korea).

Insights into measurements of water-soluble ions in PM2.5 and their gaseous precursors in Beijing

To better understand the characteristics and transformation mechanisms of secondary inorganic aerosols, hourly mass concentrations of water-soluble inorganic ions (WSIIs) in PM2.5 and their gaseous precursors were measured online from 2016 to 2018 at an urban site in Beijing. Seasonal and diurnal variations in water-soluble ions and gaseous precursors were discussed and their gas-particle conversion and partitioning were also examined, some related parameters were characterized. The (TNH3) Rich was also defined to describe the variations of the excess NH3 in different seasons. In addition, a sensitivity test was carried out by using ISORROPIA II to outline the driving factors of gas-particle partitioning. In Beijing, the relative contribution of nitrate to PM2.5 has increased markedly in recent years, especially under polluted conditions. In the four seasons, only a small portion of NO2 in the atmosphere was converted into total nitrate (TNO3), and more than 80% of TNO3 occurred in the form of nitrate due to the abundant ammonia. The concentration of total ammonia (TNH3) was much higher than that required to neutralize acid gases, and most of the TNH3 occurred as gaseous NH3. The nitrous acid (HONO) concentration was highly correlated with NH3 concentration and had increased significantly in Beijing compared with previous studies. The total chloride (TCl) was the highest in winter, and ε(Cl−) was more sensitive to variations in the ambient temperature (T) and relative humidity (RH) than ε(NO3−).

Analysis of Characteristics of Water-soluble Ions in PM2.5 in Chengdu Based on the MARGA

Water-soluble ions in PM2.5 were serially on-line monitored using the MARGA sampling and measurement system in Chengdu in 2019. Pollution characteristics of water-soluble ions were analyzed using the meteorological monitoring data. The results show that variations in the concentrations of eight water-soluble ions were consistent with the variations in PM2.5 in Chengdu. The annual average mass concentration of the total water-soluble ions was (20.2±12.7) μg ·m-3, accounting for 48.6% of the PM2.5 mass, which indicates that water-soluble ions were the major components of PM2.5. The mass concentrations of all the ions were in the order of NO3- > SO42- > NH4+ > Cl- > Ca2+ > K+ > Mg2+ > Na+. The annual average mass concentration of secondary ions was (20.2±12.7) μg ·m-3, accounting for 87.2% of total water-soluble ions. The concentrations of total water-soluble ions in different seasons were in the order of winter > spring ≈ autumn > summer. Monthly variations in total water-soluble ion concentrations followed a U-shaped curve; mass concentrations were the highest in January and December and lowest from June to August. Monthly variations in the concentrations of NO3-, SO42-, NH4+, Cl-, Na+, and K+ were consistent with the total water-soluble ion concentrations, while the concentrations of Ca2+ and Mg2+ were the highest in June. Visibility declined with the increase in the concentration of water-soluble ions, especially secondary water-soluble ions regardless of the rainfall. Light rain (accumulated rainfall in 24 h <10 mm) had no scavenging effect on water-soluble ions, while moderate and heavy rainfall had a significant effect. There was a significant positive correlation between NO3-, SO42-, and NH4+ (all the correlation coefficients were over 0.7), indicating that the mechanisms of evolution of secondary water-soluble ions in the atmosphere are highly similar to each other. The annual mean values of SOR and NOR were 0.42 and 0.12, respectively, which were negatively correlated with temperature and O3 and positively correlated with humidity, indicating that the main source of SO42- was heterogeneous oxidation reactions in the liquid phase and the main source of NO3- was heterogeneous oxidation reactions at night. The annual mean values of CE/AE and NR were 1.2 and 1.1, respectively, indicating that most aerosols in the study area were relatively alkaline. The atmospheric environment of Chengdu is rich in ammonia; thus, (NH4)2 SO4 and NH4NO3 were the main forms of secondary ions.

Seasonal Variation of Water-soluble Ions in PM2.5 in Xi'an

To explore the seasonal variations and sources of water-soluble ions, PM2.5 samples were collected from 2017 to 2018. Water-soluble ions including SO42-, NO3-, Cl-, F-, Na+, Mg2+, NH4+, K+, and Ca2+ were determined via ion chromatography. Furthermore, the existing form of NH4+, nitrogen oxidation rate (NOR), sulfur oxidation rate (SOR), and [NO3-]/[SO42-] ratio were explored. The results showed that dust, coal combustion, biomass burning, and secondary aerosols were the dominant contributors to water-soluble ions. Ca2+, SO42-, NH4+, and NO3- were the main water-soluble ions in PM2.5 in Xi'an. Correlation analysis results showed that NH4+ could not completely neutralize SO42- in spring; unneutralized SO42- could be mainly combined with K+ and Ca2+. NH4+ mainly existed in the form of ① NH4HSO4 and (NH4)2SO4 in summer; ② NH4HSO4 and NH4NO3 in autumn; and ③ (NH4)2SO4 and NH4NO3 in winter. The yearly mean values of SOR and NOR were 0.35 and 0.16, respectively, indicating a high secondary aerosol transformation rate during the study period. The [NO3-]/[SO42-] ratio showed Xi'an was mainly affected by stationary sources in spring and summer, while the contribution of mobile sources in autumn and winter was greater than stationary sources.

Characterization of Water-Soluble Ions in PM2.5 in Chongqing, a Megacity in Eastern Sichuan Basin, China

Samples of PM2.5 were collected at three urban sites and one rural site simultaneously in Chongqing, the only megacity in eastern Sichuan Basin, Southwest China, from October 15 to November 13, 2015. Water-soluble ions (WSIs, i.e., F–, Cl–, NO3–, SO42–, K+, Na+, NH4+, Mg2+ and Ca2+) in PM2.5 were measured to investigate their characteristics and formation pathways. The average concentrations of PM2.5 at the urban sites were 55.5–59.0 µg m–3, which was 62.8–73.0% higher than that at rural site. SO42–, NO3–, NH4+ were the dominant ions, contributing to more than 90% of total WSIs. The coefficients of divergence for SO42– between the urban and rural sites were 0.15–0.17, indicating its relatively uniform distribution across Chongqing. Analysis of the formation mechanisms of SO42– and NO3– in PM2.5 suggested that the heterogeneous reaction was responsible for the high concentrations of sulfate among the four sites, whereas nitrate was formed mainly through homogeneous reactions at the urban sites. Furthermore, the results of trajectory clustering showed that the air pollution were mainly from local sources within the basin. Our findings on PM2.5 composition in Chongqing help to advance the knowledge on PM2.5 pollution in Chinese megacities, and to provide more evidence for further pollution mitigation.

Analysis of PM(2.5) main pollutant components and sources in two cities in north and south of China

Objective: To analyze the pollution characteristics and source of fine particulate matter (PM(2.5)) in Shenzhen and Taiyuan, two cities in the north and south of China. Methods: PM(2.5) samples were collected from the year of 2017 to 2018. The levels of 10 heavy metal elements (Pb, Al, As, etc.) , 10 water soluble ions (F(-), Cl(-), SO(4)(2-), etc.) and 16 polycyclic aromatic hydrocarbons (PAHs) (Nap, Acy, Ace, etc.) in PM(2.5) were detected by inductively coupled plasma mass spectrometry (ICP-MS) , ion Chromatography and high Performance Liquid Chromatography respectively. USA commercial carbon analysis was applied to detect organic carbon (OC) and elemental carbon (EC) . Source of PM(2.5) was analyzed by Factor analysis method. Results: The concentrations of Pb, Mn, As, Ni, F(-), OC and EC in PM(2.5) of Taiyuan city were significantly higher than those of Shenzhen City, and the concentrations of Na(+), Cl(-), and PO(4)(3-) were lower than those of Shenzhen City (P<0.05) . Except naphthalene, the concentrations of PAHs in PM(2.5) of Taiyuan city were higher than those of Shenzhen City (P<0.05) . The main sources of metal elements and water soluble ions in PM(2.5) in Shenzhen included: industry/vehicle exhaust factor (42.64%) , construction/soil factor (34.22%) and ocean factor (17.93%) . PAHs in PM(2.5) in Shenzhen mostly came from fuel oil/vehicle exhaust factor (38.58%) , coal combustion factor (30.78%) and biomass combustion factor (24.38%) . Differently, the main sources of metal elements and water soluble ions in PM(2.5) in Taiyuan included: construction factor (30.26%) , fuel oil and coal combustion factor (24.58%) , secondary particles/soil factor (22.03%) and industry factor (18.89%) . PAHs in PM(2.5) were from fuel oil/vehicle exhaust factor (54.71%) and coal combustion factor (43.54%) in Taiyuan. Conclusion: The sources of PM(2.5) pollution are different between Shenzhen and Taiyuan, the occupational health management must be continuously strengthened, measures should be strengthened contrapuntally on the basis of different pollution sources.

Diurnal Variations and Source Apportionment of Water-soluble Ions in PM2.5During Winter in Nanjing Jiangbei New Area

To gain a better understanding of the day-night variation characteristics of water-soluble ions, PM2.5 samples were continuously collected for two months in the Nanjing Jiangbei New Area during winter. The diurnal variation and sources of water-soluble ions were studied. Results showed that the mass concentration of water-soluble ions ranged from 17.07 μg·m-3 to 168.43 μg·m-3 with a mean value of (59.01±30.75) μg·m-3. The average mass concentration of water-soluble ions in daytime was higher than that in the nighttime. The concentration ratio of NO3- and NH4+ to total ion concentrations was higher at night, while SO42- and Cl- were higher during daytime. SO42-, NO3-, and NH4+ (SNA) were the dominant species of water-soluble ions in PM2.5 in Nanjing. The mass concentration of SNA on polluted days was higher than that on clean days. The ratio of the anion-cation balance (AE/CE) was larger than 1, indicating that the PM2.5 was acidic. There was a significant linear correlation between NH4+ with NO3- and SO42-, indicating that it occurred mainly in the form of NH4NO3 and (NH4)2SO4 in PM2.5. The PMF source apportionment indicated that water-soluble ions of PM2.5 were mainly derived from motor vehicle emissions, fossil fuel combustion, biomass burning, and dust in the Nanjing Jiangbei New Area.

Fine Particulate Emission Characteristics of an Ultra-Low Emission Coal-Fired Power Plant

Since the introduction of ultra-low emissions, the characteristics of particulate matter (PM) emissions from coal-fired power plants have changed. We quantitatively evaluate the emission characteristics of each component in PM and the impact of purification equipment by analyzing three ultra-low emission units of coal-fired power plants (FP1, FP2, and FP3). A DGI was used to sample particles from the wet flue gas desulfurization (WFGD) unit and wet electrostatic precipitator (WESP) inlet and outlet, which were then analyzed by various methods. The results showed that the mass concentrations of PM1, PM2.5, and PM10 discharged from the outlets of the three units were 0.25-0.38, 0.31-0.42, and 0.42-0.57 mg·m-3, respectively, and that the mass concentration of PM10 discharged under the two kinds of units was equivalent. However, there were differences in the particle size distribution and composition of the particles. In comparison to the FP1 and FP2 units, the PM2.5/PM10 ratio of the FP3 unit was the highest. A possible reason for this is that the unit was equipped with a WESP, which can better remove particle sizes of 2.5 μm or more. The total concentrations of water-soluble ions in PM2.5 discharged from the FP2 and FP3 units were 0.20 and 0.06 mg·m-3, respectively. The water-soluble ions emitted from the FP2 unit were mainly Ca2+ and SO42-, whereas those mainly emitted from the FP3 unit were NH4+ and SO42-. Analysis of the PM from the WFGD import and export of the FP2 unit showed that the WFGD process increased the water-soluble ion discharge by entraining the desulfurization slurry containing limestone and gypsum. Addition of a WESP after WFGD can effectively remove PM2.5 and PM10 particles and reduce the influence of water-soluble ions on the atmospheric environment.

Seasonal Characteristics and Source Analysis of Water-Soluble Ions in PM2.5 of Anyang City

We explore the characteristics and sources of water-soluble ions in aerosol fine particulate matter (PM2.5) samples collected from Anyang, China, during typical seasonal months from 2018 to 2019. Nine water-soluble ions (Na+, NH4+, K+, Mg2+, Ca2+, F-, Cl-, NO3-, and SO42-) were analyzed. The analysis of PM2.5, water-soluble ion concentration levels, anion-cation balance, nitrogen oxidation rate (NOR), sulfur oxidation rate (SOR), and ion correlation showed that the annual average concentrations of PM2.5 and water-soluble ions in Anyang were (85.81±45.43) μg·m-3 and (48.21±30.04) μg·m-3, respectively. Concentrations of ions were ranked as:NO3- > SO42- > NH4+ > Cl- > K+ > Ca2+ > Na+ > Mg2+ > F-. The annual average concentration of the sum of NH4+, NO3-, and SO42- was (42.72±27.87) μg·m-3, which accounted for 87.14% of total water-soluble ions. Moreover, NH4+ was highly related to SO42- and NO3-. The mean values of the nitrogen oxidation rate (NOR) and sulfur oxidation rate (SOR) were 0.25 and 0.37, respectively. These results suggest that these ions were the result of secondary formation. The anion-cation charge equivalent value was 0.75-0.94, which indicates that the sampled aerosols were alkaline. NH4+ mainly existed in the form of (NH4)2SO4 and NH4NO3 in spring, summer, and autumn, whereas in winter it mainly existed in the form of NH4Cl. The results of principal component analysis indicated that secondary aerosols, coal combustion, biomass burning, and dust were the main sources of the water-soluble ions in Anyang during the sampled periods.

PM2.5 Associated Phenols, Phthalates, and Water Soluble Ions from Five Stationary Combustion Sources

ABSTRACT Phenols and phthalates (PAEs) are always linked with the formation of secondary organic aerosols (SOA), while the water soluble ions (WSIs) are connected to the formation of secondary inorganic aerosols (SIA). A total of PM2.5 associated 20 phenols, 6 phthalates, and 9 WSIs were detected using GC-MS, ICS-1100, ICP-OES, and UV-VIS spectrophotometer for 5 stationary incineration sources including the domestic garbage (DG), garbage-fired power plant (GFPP), workshop of cable combustion for metal reclamation (WCC), peanut straw (PS), and wheat straw (WS). The anion equivalent (AE) and cation equivalent (CE) concentrations indicated that the emitted PM2.5 was alkaline for all the 5 combustion sources. Cl– possessed high contents among all the 5 burning sources and the highest value occurred at WCC due to the high Cl content in PVC. The WSI profiles were different from each other for the 5 incineration sources on the basis of high coefficients of divergence (CDs). The mass contributions of 9 WSIs in PM2.5 from 5 sources were far lower than those of atmospheric PM2.5. DEHP and DBP dominated in PM2.5 from 4 sources, while WCC possessed high levels of DEHP, DNOP, and DBP. WCC possessed the highest daily intakes of PAEs due to its highest ∑6PAEs of 32000 ng g–1 resulted from the high usage of plasticizers in PVC. The PAE profile similarities were found for both GFPP vs. DG and PS vs. WS based on low CDs. Only 11 phenols were detected for the 5 sources and WCC possessed the highest level of phenols although only phenol was detected. WS had the high levels of phenols due to the using of phenolic pesticides during wheat growth process.

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

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.