Water-soluble Ionic Components Research Articles

Chemical characteristics, morphology and source apportionment of PM10 over National Capital Region (NCR) of India.

The present study frames the physico-chemical characteristics and the source apportionment of PM10 over National Capital Region(NCR) of India using the receptor model's Positive Matrix Factorization (PMF) and Principal Momponent Mnalysis/Absolute Principal Component Score-Multilinear Regression (PCA/APCS-MLR). The annual average mass concentration of PM10 over the urban siteof Faridabad, IGDTUW-Delhi and CSIR-NPL of NCR-Delhi were observed to be 195 ± 121, 275 ± 141 and 209 ± 81µgm-3, respectively. Carbonaceous species (organic carbon (OC), elemental carbon (EC) and water-soluble organic carbon (WSOC)), elemental constituents (Al, Ti, Na, Mg, Cr, Mn, Fe, Cu, Zn, Br, Ba, Mo Pb) and water-soluble ionic components (F-, Cl-, SO42-, NO3-, NH4+, Na+, K+, Mg2+, Ca2+) of PM10were entrenched to the receptor models to comprehend the possible sourcesof PM10. The PMF assorted sources over Faridabad were soil dust (SD 15%), industrial emission (IE 14%), vehicular emission (VE 19%), secondary aerosol (SA 23%) and sodium magnesium salt (SMS 17%). For IGDTUW-Delhi, the sources were SD (16%), VE (19%), SMS (18%), IE (11%), SA (27%) and VE + IE (9%). Emission sources like SD (24%), IE (8%), SMS (20%), VE + IE (12%), VE (15%) and SA + BB (21%) were extracted over CSIR-NPL, New Delhi, which are quite obvious towards the sites. PCA/APCS-MLR quantified the similar sources with varied percentage contribution. Additionally, catalogue the Conditional Bivariate Probability Function (CBPF) for directionality of the local source regions and morphology as spherical, flocculent and irregular were imaged using a Field Emission-Scanning Electron Microscope (FE-SEM).

PM10 within Indian standard is achievable by mitigating the sources of PM1: A thirteen years (2009–2021) long study and future prediction (2024) over the eastern Himalayas, India

A thirteen years-long (2009–2021) study was conducted on PM10 pollution over a high-altitude station, Darjeeling (27.1° N and 88.15° E, 2000 m amsl) in the eastern Himalayas in India. To better understand the sources and build a proper mitigation strategy for PM10, we have segregated PM10 into PM1 and PM1-10 using the Anderson cascade impactor. A total of 620 sets of samples were collected during the entire study period. PM10 was found to remain within its Indian standard (60 μg m−3) in every year of the study period (long-term average PM10: 46 ± 8 μg m−3). PM10 pollution during winter (74.0 ± 15.1 μg m−3) and premonsoon (73.1 ± 12.1 μg m−3) was highest compared to other seasons. Bi-modal mass size distribution of composite PM10 was observed for all the seasons with maximum peak intensity at the finer mode (PM1). Most of the anthropogenic water-soluble ionic components as well as carbonaceous aerosols exhibited maximum intensity at PM1 too. PM10 exhibited a steady decrease from 2009 to 2013 but since 2014, a sharp rise was observed. Further, we have observed that premonsoon and winter-time PM1 pollution was the key factor for a such high rise in PM10. PM1 increased sharply at a rate of 4.1 μg m−3 yr−1 in premonsoon and 3.3 μg m−3 yr−1 in winter since 2014. Auto regressive integrated moving average (ARIMA) model for future prediction revealed that PM10 would cross its Indian standard and PM1 alone would cross the PM2.5 standard in 2024 if the current scenario remains the same and the city would be enlisted among the “non-attainment” cities of the country under “National Clean Air Program (NCAP)” of Government of India. The Positive matrix factorization (PMF) model was run to apportion the sources of PM1 and PM10. It was observed that the vehicular emissions in premonsoon (33% in PM1; 28% in PM10; contribution of vehicular emission in PM1 to PM10 > 90%) and biomass burning in winter (27% in PM1; 23% in PM10; contribution of PM1 to PM10 > 80%) are the most influencing sources that need to be curbed to mitigate PM1 and hence PM10 pollution over Darjeeling.

The Unignorable Near-ground PM2.5, UFP, PAHs, and BC Levels around a Traffic Prohibited Night Market

In some special densely populated areas, the background atmospheric fine particulate matter (PM2.5) concentration is very high, which makes near-ground (NG) exposure a major problem endangering human health. In our study, the night market in Chiayi City was selected as the research object and collected the 24-hour PM2.5 samples through the federal reference method (FRM), characterizing the mass concentration, water-soluble ionic components, carbon specious, metal compositions and source contributions of PM2.5. To better analyze the contribution of traffic sources under different sampling conditions, the mobile real-time monitoring system was used to analyze the quality of NG-PM2.5, the number of ultra-fine particles (UFP), the concentration of black carbon (BC) and total polycyclic aromatic hydrocarbons (PAH) before and after the traffic restriction. Results indicated the concentration of PM2.5 was 7.26–58.6 mg m-3. In chemical analysis, secondary contents e.g., carbonaceous and ionic components accounted for ~60% of the PM2.5, supporting the importance of long-range transport. However, the traffic contribution accounted for ~30% and hardly changed between different samples, which was not conducive to source apportionment. Through traffic restriction, it was found that all kinds of pollutants increased significantly before restriction, and even after restriction, the concentrations of PM2.5 and BC increased 131% and 151% in low concentration season. In the high concentration season, the traffic restriction significantly reduced the NG-UFP and NG-PAH concentration by 27% and 55%, respectively, but NG-BC and NG-PM2.5 was almost unaffected. Therefore, besides the contribution of traffic source, emissions from cooking activities are very important for the increase of NG-PM2.5 levels in the night market area.

Sources apportionment of water-soluble inorganic salts in CPM from coal-fired power plants with different emission control technologies

Different control technologies to reduce emissions of sulfur oxides and nitrogen oxides from coal-fired boilers have been adopted globally, leading to significant reductions in these gas emissions, especially over the past several years in China. Comparatively, little attention has been paid to the potential effects of these control technologies on particulate matter (PM) emissions, especially condensable particulate matter (CPM), which is harmful to the atmosphere and human health. In this study, we measured filterable and condensable PM emissions in five coal-fired commercial-scale boilers installed with SNCR or SCR for NOx control and wet, semidry, or dry flue gas desulfurization (FGD) for SO2 emission controls. Water-soluble ionic components in PM were analyzed. The experimental results show that the CPM accounts for 55.9% to 95.1% of total particulate matter (TPM) and is composed primarily of water-soluble SO42- and NH4+, with (NH4)2SO4 being the dominant CPM aerosols. Experimental results also reveal that the flue gas emission control technology significantly affects CPM emission from coal-fired boilers. Since the production of (NH4)2SO4-rich CPM results from the use of ammonia solution for NOx reduction, boilers emit more CPM with SNCR than with SCR because the former operates with a higher ammonia/NOx ratio than the latter. Additionally, the CPM emission is related to the FGD technology installed. Boilers installed with wet FGD emit the lowest CPM, followed by semidry and dry FGDs, because of their decreased capabilities of dissolving and absorbing water-soluble components.

Using Stable Sulfur Isotope to Trace Sulfur Oxidation Pathways during the Winter of 2017-2019 in Tianjin, North China.

After the implementation of the Coal Replacing Project (CRP) in the northern parts of China in 2017, its effect on PM2.5 composition is still unclear. In the study, water-soluble ionic components (WSICs) and stable sulfur isotope ratios (δ34S) of SO42− in PM2.5 collected during the domestic heating period before and after the implementation of CRP in Tianjin were analyzed. Results showed that the average concentrations of both PM2.5 and WSICs have dropped dramatically after the CRP, especially for the SO42− (by approximately 57–60%). After the CRP, the range of δ34Ssulfate was significantly narrowed to 4.1–7.5‰ in January 2018 and 1.4–6.1‰ in January 2019, which suggested that the sulfur source was becoming simple. It was interesting that the δ34Ssulfate value in the pollution period before the CRP was higher than that in the clean period, whereas it showed the opposite tendency after the CRP, which implied that the contribution of sea salt was high during the pollution period before the CRP. The MIXSIAR model calculated that the contributions of the transition-metal ion (TMI) oxidation and NO2 oxidation pathways in the three sampling stages were higher than those of the OH radical oxidation and H2O2/O3 oxidation pathways, indicating that the formation pathway of sulfate was mainly dominated by heterogeneous oxidation. Before the CRP, the NO2 oxidation pathway was the dominant sulfate oxidation pathway during a haze episode, and the TMI oxidation pathway dominated the formation of sulfates after the CRP.

Seasonal variations in characteristics, sources and diurnal patterns of carbonaceous and water-soluble constituents in urban aerosols from the east coast of tropical India

Environmental context The export of various man-made pollutants from northern India has a large impact on aerosol formation processes, their transformations and regional environmental chemistry over tropical peninsular India. The quantitative source apportionment of organic aerosols performed in this study provides a better understanding of their sources and implications for climate and air-quality management policies in South Asia. Abstract This study highlights seasonal characteristics, sources, daytime (sea-breeze) and night-time (land-breeze) variations of carbonaceous and water-soluble ionic components in PM10 (<10 µm particulate matter) aerosols from the east coast (Chennai city) of tropical India. Elemental and organic carbon (EC and OC) were found to be higher in winter when air masses were delivered from the northern part of India covered by the Indo-Gangetic-Plains whereas lower concentrations were observed during summer and monsoon associated with marine air masses. Sea salts (Na+ and Cl–), dust (Ca2+ and Mg2+) and nitrates (NO3–) were found to be highest in monsoon, suggesting these species may be co-transported over the sampling site with marine air masses. Using air mass back-trajectory analysis, linear relationships between chemical species and specific mass ratios, we demonstrate that east coast urban aerosols are strongly influenced by aged anthropogenic sources including biomass burning in winter and post monsoon while aged marine emissions mixed with local pollutants (dust and vehicular) are important in monsoon and summer. Further, the mesoscale phenomenon was reflected in measured chemical constituents during the study period. Positive-matrix-factorisation (PMF) analysis confirmed that OC aerosols are largely attributable to chemically aged anthropogenic (53 % in the day and 39 % in the night) and combustion-derived (17 % and 39 %) sources in winter and sea salts mixed with dust and vehicular emissions (61 % and 52 %) during monsoon. These important insights about the sources and formation processes of organic aerosols will help in understanding the formation of atmospheric brown clouds over south Asia.

Coal and biomass burning as major emissions of NOX in Northeast China: Implication from dual isotopes analysis of fine nitrate aerosols

Abstract In recent years, there are still huge amounts of NOx emissions in the Northeast, and this inevitably increases the concentration of aerosol nitrate (NO3−), which plays an important role in atmospheric pollution. Because of the mixed complicated sources of atmospheric NO3−, it is difficult to quantify their contribution, and the use of certain means to identify their sources and pathways is critical to developing effective control measures. Since different sources of NOX have different ranges of δ15N values, δ15N is considered to be a useful tool for identifying the source of aerosol NO3−. But isotope fractionation is produced during the conversion of NOX to NO3−, and δ18O can be used to estimate its isotope fractionation value. In this study, daily PM2.5 samples were collected in four seasons from Northeast China, and their water-soluble ionic components (WSIs), δ15N–NO3- and δ18O–NO3- were analyzed. The isotope fractionation value of δ15N in which NOX was converted to NO3− was estimated and the contribution of different sources was quantified in combination with the Bayesian model. The results showed that NO3− was the most important inorganic ion component in the WSIs with the highest annual average ratio of 21.1%. Both δ15N and δ18O showed higher in winter (δ15N: 13.79‰±2.17‰; δ18O: 70.50‰±10.02‰) than in summer (δ15N: 2.69‰±2.95‰; δ18O: 58.67‰±4.52‰). The daytime OH pathway was considered to play a leading role in nitrate formation, with the annual average contribution of 61.0 ± 18.8%. NOx was mainly from the contribution of coal combustion (34.5%) and biomass burning (34.3%) followed by traffic (19.5%) and biological soil (11.7%). During heating periods, NOx was dominated by coal combustion with the average contribution of 46.9% whereas biomass burning was the most important contributor during non-heating periods (39.5%). Therefore, controlling coal consumption and biomass burning can drastically reduce concentration of aerosol NO3− in Northeast China.

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.

The Role of PM2.5 Chemical Composition and Meteorology during High Pollution Periods at a Suburban Background Station in Southern Poland

This study conducted measurements of PM2.5 (particulate matter with a diameter ≤ 2.5 µm) in Racibórz, Poland, during 2018. Samples were collected daily and analyzed for their chemical composition, specifically, the carbonaceous (elemental and organic carbon) and water-soluble ionic (Cl–, NO3–, SO42–, Na+, NH4+, K+, Ca2+ and Mg2+) components. Additionally, the secondary inorganic aerosol (SIA) as well as the secondary and primary organic carbon (SOC and POC, respectively) content was estimated. To identify the causes of elevated PM2.5 concentrations, the contributions of these chemical species were further investigated, and the role of meteorological factors was also examined. During the measurement period, PM2.5 concentrations exceeding 50 µg m–3 were recorded on 38 days, and 7 pollution episodes were detected. Such events, however, were observed only in the heating season, when stable meteorological conditions (low air temperatures, weak winds, high relative humidity and lack of precipitation) and increased emissions of PM and its precursors from anthropogenic sources favored the accumulation of pollutants. The PM2.5 was dominated by carbonaceous aerosol, especially POC, although the SOC rose significantly during high pollution periods. Furthermore, the fraction of SIA clearly decreased as the concentration of PM2.5 increased, and its variability was greatly affected by regional and/or long-range transport events. Our results can help guide the development of effective strategies for reducing air pollution from fine particulate matter. Such control measures are particularly important in Poland, where PM2.5 concentrations remain high compared to many European countries.

The Mechanisms Responsible for the Interactions among Oxalate, pH, and Fe Dissolution in PM2.5

In this study, 10-year records of PM2.5 oxalate concentrations in six urban and rural Canadian monitoring sites are analyzed along with the time series of other water-soluble ionic components, water-soluble metals, and aerosol pH to identify the major factors influencing its abundance and speciation. Oxalate was found to have higher mass loadings relative to sulfate and nitrate when the temperature was higher and the aerosol was more acidic, which is counter to the gas/particle phase partitioning expected from the effective Henry’s Law constant. However, a strong correlation was found between oxalate and water-soluble Fe (WS-Fe), with a slope between 1.3 and 4.6, suggesting that the major forms of the particulate oxalate were in complexes with WS-Fe, whose concentration was also found to be significantly impacted by aerosol pH. When aerosol exhibits pH around 2, the proton-promoted dissolution of Fe leads to a strong relationship between WS-Fe and pH, indirectly supporting higher oxalate levels in more acidic particles. Meanwhile, higher aerosol pH in wintertime favors oxalate to fully partition into the particle phase, but higher WS-Fe concentration in aerosol liquid water was also often observed when aerosol had higher oxalate concentration. This phenomenon suggests that the chelating-promoted dissolution mechanism induced by oxalate can enhance Fe dissolution in wintertime. Our results reveal that the interactions among pH, oxalate. and Fe exhibit strong seasonality, and an improved understanding of these mechanisms is important for the environmental fate studies of both organic acids and metals.

Chemical speciation of water-soluble ionic components in PM2.5 derived from peatland fires in Sumatra Island

We conducted a field study to characterize water-soluble ionic species in PM2.5 from peatland fires using ground-based samplings at fire sources and receptor sites in the Riau Province, Sumatra, Indonesia. We determined the concentrations of PM2.5 mass, water-soluble ions, and some chemical elements. Through PM2.5 field samplings at three peatland fire sources, we have shown that the mass fractions of typical peatland fire water-soluble ionic components tend to differ between peatland fire sources. Thus, our results indicate that PM2.5 source profiles of water-soluble ionic components for peatland fire must be selected with extreme caution if applied to a receptor model. From the viewpoint of ionic composition of each peatland fire sample, Cl− and NH4+ were consistently dominant anions and cations, respectively, for all peatland fire samples, i.e., NH4Cl was a consistently dominant component. Through field samplings of the ambient PM2.5 in Pekanbaru during peatland fire-induced haze and non-haze periods, we found differences in PM2.5 mass and total water-soluble ionic component concentrations between haze and non-haze samples. Four components, C2O42−, NO3−, SO42−, and NH4+, showed highly elevated levels during haze periods. Since these four ions are recognized as the major secondarily formed aerosol components, the increased total concentrations of water-soluble ionic components during haze periods can mainly be derived from the gas-to-aerosol conversion process. The ionic compositions of haze samples at receptor sites are obviously different from those at peatland fire source samples. In particular, NH4Cl, which is characteristic of peatland fire PM2.5 sources, is low at sites during haze periods.

Study on bulk to single particle analysis of atmospheric aerosols at urban region

The massive increase in emission of air pollutants due to the economic and industrial growth has made the air quality a crucial health and environmental problem. Present study describes the seasonal variation of water soluble ionic components, carbonaceous species and their emission sources from April 2013 to November 2014 at Pune, India. Morphology and surface elemental composition of single particle was also studied by using SEM-EDS. Average PM2.5 and PM10 mass concentrations were 98 ± 28 and 148 ± 45 μg m−3, respectively that substantially exceeded than Indian NAAQS and WHO standards limit values. Seasonal analysis of PM indicated higher concentrations during winter as compared to the rest of the seasons. Chemical analysis of PM accounted for ~40% for ionic components and 36% for carbonaceous species annually for fine mode whereas in coarse mode it accounted for ~28 and 24% for ionic component and carbonaceous species, respectively. This revealed that chemical species are more attributed to fine mode as compared to coarse mode size particles. Contribution of SOC was higher in comparison to POC throughout the study due to abundance of organic constituents. SO42−/EC ratios and ECR values indicates the abundance of scattering type aerosols than absorbing type aerosols. Morphology and surface elemental analysis of PM reveals the presence of soot and alumino-silicates particles. Size, shape and chemical species of aerosol are significantly varied with synoptic scale. Trajectory analysis reveals long range transportation of aerosols over receptor site from various regional and global environments. Measured data on bulk to single particle analysis is extremely useful as input data in climatic aerosol model and provide a more complete relevant picture of aerosol for scientific community with respect to urban air pollution.

Aerosol pollution in a megacity of southwest China inferred from variation characteristics of sulfate-δ34S and water-soluble inorganic compositions in TSP

Daytime and nighttime aerosol samples for total suspended particles (TSP) were collected in Chengdu from 12 to 23 January 2013 (winter) and 10 to 21 August 2014 (summer). The mass concentrations of TSP, major inorganic ions, and stable sulfur isotope ratios were determined. Clear winter–summer variation in TSP was observed; the mass concentrations of TSP in summer were below levels defined by the Chinese National Ambient Air Quality Standard (GB3095-2012), whereas winter TSP levels exceeded the standard by 2–4 times. Overall, the sum of SO42−, NO3−, and NH4+ concentrations represented the highest contribution to water-soluble ionic components, which showed similar trends to TSP mass. According to correlations among major ions, the major compounds in TSP were likely to be (NH4)2SO4, NH4NO3, CaCl2, and KCl in both sampling times, and CaSO4 and Ca(NO3)2 were also present in summer. The NO3−/SO42− ratios ranged from 0.57 to 1.28 (average 0.85±0.16) in winter and 0.5 to 0.93 (average 0.66±0.11) in summer, indicating stationary source emissions (coal burning) were more important sources than the vehicle exhaust. The relationship between SO42− and δ34S indicated the sulfate sources were affected by the low sulfur isotope value of biogenic sulfur release in summer, and the high sulfur isotope value of coal in winter. As a whole, the mixture of coal burning and vehicle exhaust represent the major TSP sources in Chengdu in the study period, and biogenic sulfur also contributes to TSP in summer.

Stable carbon and nitrogen isotopic composition of PM10 over Indo-Gangetic Plains (IGP), adjoining regions and Indo-Himalayan Range (IHR) during a winter 2014 campaign

For source identification, a field campaign involving simultaneous sampling of particulate matter (PM10) was conducted at eight sampling sites in the Indian mainland during winter 2014. The sampling sites include Delhi (upper IGP), Lucknow (middle IGP), and Kolkata (lower IGP) in the Indo-Gangetic Plains (IGP); Mohal-Kullu and Darjeeling in the Indo-Himalayan Range (IHR). In addition, Ajmer, located upwind of the IGP in NW-India and Giridih and Bhubaneswar, in the downwind to the IGP has also been chosen. To characterize the sources of the ambient PM10, stable isotope ratios of carbon (δ13CTC) and nitrogen (δ15NTN) for the total carbon (TC) and total nitrogen (TN) fractions have been considered. Ancillary chemical parameters, such as organic carbon (OC), elemental carbon (EC), and water-soluble ionic components (WSIC) mass concentrations are also presented in this paper. There was very small variation in the daily average δ13CTC ratios (- 24.8 to - 25.9‰) among the sites. Comparison with end-member stable C isotopic signatures of major typical sources suggests that the PM10 at the sites was mainly from fossil fuel and biofuel and biomass combustion. Daily average δ15NTN ratios were not observed to vary much between sites either (8.3 to 11.0‰), and the low δ15NTN levels also indicate substantial contributions from biofuel and biomass burning of primarily C3 andC4 plant matter. Graphical abstract Scatter plot of the average (± 1 standard deviation (SD)) δ13CTC (‰) compared to δ15NTN (‰) at the sampling sites.

Seasonal Variations in Particle Size Distribution and Water-soluble Ion Composition of Atmospheric Particles in Chengdu

Size-resolved atmospheric particles were collected monthly from February 2012 to January 2013 on the campus of Chengdu University of Technology using the Anderson multi-stage impactor sampler. The mass concentrations of these samples and the contents of nine water-soluble ion species were analyzed. The results showed that the annual average concentrations of PM2.1 and PM11 in Chengdu during the sampling period were (125.9±56.14) μg·m-3 and (224.5±83.64) μg·m-3, respectively. The highest mass concentration of particulate matter was observed in winter, followed by spring while the lowest was in autumn. The average content of water-soluble ions in particulate matter in Chengdu was about 37.15 μg·m-3 and the order of water-soluble ion mass concentrations was SO42- > NO3- > NH4+ > Ca2+ > Cl- > Mg2+ > K+ > Na+ > F-. Meanwhile, SO42-, NO3-, and NH4+ were the major water-soluble ionic components that accounted for 78% of total water-soluble ions. Unimodal distribution was observed for SO42-, NO3-, and NH4+ mainly in fine particles, while Ca2+ and F- were concentrated in coarse particles and their distribution was also unimodal. Similar size distributions were found for Cl- and K+, as well as Mg2+ and Na+, both of which were bimodal. The content of water-soluble ions in both fine and coarse particles during winter and spring was significantly higher than that in summer and autumn in Chengdu. Based on the correlation analysis for major ions, SO42-, NO3-, and NH4+ in fine particles are likely in the form of (NH4)2SO4, NH4HSO4, and NH4NO3. In coarse particles, the major water-soluble ions (i.e. SO42-, NO3-, and Ca2+) might exist in the forms of Ca(NO3)2 and CaSO4. The secondary formation processes, soil dust, and biomass burning are the major sources of water-soluble ion species in the particulate matter in Chengdu.

Concentration, Water-Soluble Ionic and Polycyclic Aromatic Hydrocarbons Composition and Sources of PM2.5 During Summer in Hongshan District, Wuhan

Atmospheric PM2.5 samples were collected in Hongshan district, Wuhan from June 12th to July 22th, 2014. This study analyzed the characteristics and chemical composition of PM2.5, and the concentrations of Polycyclic Aromatic Hydrocarbons (PAHs) were analyzed by gas chromatography-mass spectrometry (GC-MS), to discuss the pollution sources and formation mechanism. The results indicated the total concentrations of PM2.5 ranged from 36.41 to 220.02 μg·m-3, with the mean of 97.38 μg·m-3. and the exceeding criteria rate was 59.26%. Furthermore, the concentration of PM2.5 correlated significantly with wind speed in meteorological parameters, when the wind speed increased, the concentration of PM2.5 showed a trend of decline. The water-soluble ionic components of PM2.5 were SO42-, NO3-, NH4+ and K+ which accounted for 40.67%, and the aerosol partial acid. The influencing factors of formation process of SO42- were different from those of NO3-, and NH4HSO4 and (NH4)2SO4 were the main compounds of NH4+ in PM2.5. The average concentration of PAHs in PM2.5 was 11.30 ng·m-3, and the dominant compounds were 4-6 ring PAHs. Industrial waste gas and vehicle emissions were the sources of PM2.5. The various sources of the PAHs had contribution of 83.90% from vehicle emission and combustion of coal, 10.17% from petroleum sources, and 5.08% from coking emission. The concentration of toxic benzo[a]pyrene equivalent (TEQBaP) ranged from 0.22 to 11.19 ng·m-3 (mean, 1.74 ng·m-3), and the exceeding criteria rate was 7.41%.

Characteristics and Source Apportionment of Atmospheric PM2.5 at a Coastal City in Southern Taiwan

ABSTRACTFine particulate matters (PM2.5) has been identified as one of the major air pollutants in urban areas, which are responsible for the adverse effects on public health and the deterioration of visibility. New PM2.5 air quality standards were promulgated in Taiwan on 14th May 2012, as well as the standard sampling and analytical method for atmospheric PM2.5 (NIEA A205.11C) on 24th April 2012. In this study, the atmospheric levels and characteristics of PM2.5 in Tainan during 2013 were evaluated by measuring the mass concentration of PM2.5 and analyzing the water-soluble ionic, carbon, and metal components. Additionally, a Chemical Mass Balance (CMB) receptor model was used to identify possible sources of PM2.5 and their contributions. Based on results of this study, the current PM2.5 levels in Tainan in spring and winter (41–49 µg m–3) were substantially higher than the yearly average PM2.5 air quality standards (15 µg m–3). According to chemical composition analysis, secondary aerosols (NH4+, NO3–, and SO42–) contributed approximately 50% and 60% of PM2.5 mass in spring and winter respectively; but were responsible about 40% by mass in summer at both Tainan and Xinying stations. From the results of CMB model, the main contribution sources to the PM2.5 in Tainan are traffic emissions (31.5%), ammonium sulfate (25.5%), ammonium nitrate (12.5%), and crustal elements (11%). Consequently, to improve PM2.5 of Tainan City, the priority control pollutants (or sources) are primary PM2.5 (open burning, construction sites and road dust by vehicles), NOx (diesel vehicle emissions), and SOx (fuels).

부산 도심지역 대기중 입자상물질의 크기분포에 따른 수용성 이온성분의 특성

Abstract This study was conducted to investigate size distribution characteristics of water-soluble ionic components in the airborne particulate matter(PM) collected from an urban area in Busan using a MOUDI cascade impactor from March to October 2010. The inorganic constituents in the fine particles( ≤ 1.8μm) predominantly consisted of sul-fate, nitrate, ammonium, and potassium. Sulfate and ammonium concentrations showed a high correlation and sim-ilar equivalent concentrations in the fine modes including 0.18~0.32μm, 0.32~0.56μm, and 0.56~1.0μm. This indicates that the main chemical component in the fine particles would be forms of ammonium sulfate such as (NH 4 ) 3 H(SO 4 ) 2 , (NH 4 ) 2 SO 4 , and (NH 4 )HSO 4 . Back trajectory analysis showed that relatively higher concentrations of ammonium, nitrate, and sulfate in the fine mode, compared to the coarse mode, are caused both by domestic sources and long-range transports originated from China continent. High concentration episodes of PM both in the fine mode and the coarse mode were attributed both by anthropogenic sources, such as ship emissions and traffic emissions, and by natural sources such as seawater(sea salt), respectively.

Water Soluble Ionic Components in Particulate Matter (PM10) during High Pollution Episode Days at Mohal and Kothi in the North-Western Himalaya, India

Particulate pollutants and their water soluble ionic components were collected and analyzed on the occasion of high pollution episode days in the period 2009 to 2011. Among the water soluble ionic constituents at Mohal (valley base), SO_4 ^(2-) (34%) was the largest contributor; followed by Cl^- (20%), NO_3 ^- (17%), Ca^(2+) (9%), Na+ (7%), NH_4 ^+ (5%), F^- (2%), Zn^(2+) (2%) and Mg^(2+) (1%). While at Kothi (hill slope), Cl– (27%) was the largest contributor; followed by SO_4 ^(2-) (25%), NO_3 ^- (14%), Na^+ (11%), Ca^(2+) (9%), NH_4 ^+ (7%), K^+ (3%), F^- (3%) and Zn^(2+) (1%). The average ratios of NO_3 ^- + Cl^-/SO_4 ^(2-) were 1.08 and 1.64 for Mohal and Kothi, respectively; indicating that a small fraction of HNO_3 and HCl influenced the acidic nature of ions. The mass ratios of NH_4 +/NO_3 ^- and NH_4 +/SO_4 ^(2-) were 0.29, 0.5 and 0.15, 0.28; at Mohal and Kothi, respectively. The ratios were below unity showing the predominance of NH_4NO_3 and (NH_4)_2SO_4 in the atmosphere. The descending order of neutralizing factors were observed as Ca^(2+) ＞ NH_4 ^+ ＞ K^+ ＞ Mg^(2+) assuming that the origin is of a crustal source. The non-sea salt fraction for Mohal was found in the descending order of Cl^-, Ca^(2+) and SO_4 ^(2-), which are more than 50% of the total ions except Mg^(2+) and K^+. While for Kothi, the percentage of Cl^- and SO_4 ^(2-) stood to be more than 50% indicating that these ions are of non-marine origin. The first factor from principal component analysis for Mohal explains 75.59% of the total variance i.e., highly loaded with NH_4 ^+ (0.986), K^+ (0.685), F^- (0.935), Cl^- (0.919) and Zn^(2+) (0.969) indicating influence of anthropogenic activities on PM10 concentration. While at Kothi, the first factor explains 45.41% of the total variance, highly loaded with K^+ (0.981), SO_4 ^(2-) (0.965), NO^(3-) (0.953) and Zn^(2+) (0.948) also indicating influence of anthropogenic activities in the region.

Water Soluble Ionic Species in the Atmospheric Fine Particulate Matters (PM2.5) in a Southeast Asian Mega City (Dhaka, Bangladesh)

Atmospheric fine particulate matters (PM2.5) were collected with an Envirotech Instrument (Model APM 550) at the roof of Khundkur Mukarram Hussain Science Building, University of Dhaka, Bangladesh between January and February, 2013. PM2.5 samples were collected on Quartz fiber filters during day and night time. Water soluble ions (sulfate, nitrate, phosphate, chloride, bromide, sodium, potassium and calcium) were analyzed with Ion Chromatography (Model 881, Metrohm Ltd., Switzerland) and Flame photometer (Model PFP7, Jenway, UK). Average PM2.5 mass was 136.1 μg&#183m&#453 during day time and 246.8 μg&#183m&#453 during night time with a total average of 191.4 μg&#183m&#453. Nighttime PM2.5 concentration was about double compared than that of daytime presumable due to the low ambient temperatures with high emissions from heavy duty vehicles. The 24-hour average PM2.5 mass (average of day and night) was about eight times higher than WHO (25.0 μg&#183m&#453) and about three times higher than DoE, Bangladesh (65.0 μg&#183m&#453) limit values. The total average concentrations of sulfate, nitrate, phosphate, bromide, chloride, sodium, potassium and calcium were 5.30, 7.75, 0.62, 0.16, 1.19, 1.30, 8.11, and 3.09 μg&#183m&#453, respectively. The concentrations of the water soluble ions were much higher during nighttime than daytime except nitrate, bromide and potassium. Excellent correlations were observed between sulfate and nitrate, sodium and chloride, bromide and phosphate indicating joint sources of origin. Potassium, sulfate, nitrate and calcium are the most dominant species in PM2.5. Water soluble ionic components in Dhaka contributed about 15% mass of the PM2.5. Ratio analysis showed that sodium and chloride were from mainly sea salt. Potassium has varieties of sources other than biomass burning. Sulfate and nitrate are mainly from fossil fuel origin. This is the first study of the day and night variation of the water soluble ionic species at the fine particulate matters (PM2.5) in Bangladesh.