Chemical Characterization Of PM2 Research Articles

Estimation of Particulate Matter (PM10) Over Middle Indo-Gangetic Plain (Patna) of India: Seasonal Variation and Source Apportionment

Despite extensive research on particulate matter (PM) pollution in India’s Indo-Gangetic Plain (IGP), source apportionment remains challenging. This study investigates the effect of particulate matter (PM10)-associated water soluble inorganic ions (WSIIs) on ambient air concentration across the middle IGP from January to December 2018. Moreover, the seasonal fluctuation and chemical characterization of PM10 were assessed for the year 2018. The results revealed a high concentration of PM10 (156 µg/m3), exceeding the WHO and National Ambient Air Quality Standard (NAAQS) limits. The highest PM10 levels were observed during autumn, winter, summer, and the rainy season. The study identified SO42− and NH4+ as the most common WSIIs, constituting 46% and 23% of the total WSIIs. Source apportionment analysis indicated that street dust, biomass burning, and vehicle and industrial emissions together with secondary formation significantly contributed to IGP’s PM pollution. Additionally, the investigation of air mass back trajectory suggests that air quality in IGP is largely influenced by eastern and western Maritime air masses originated from the Arabian Sea, the Bay of Bengal, Gujarat, Afghanistan, Pakistan, and Bangladesh.

Year-long and seasonal differences of PM2.5 chemical characteristics and their role in the viability of human lung epithelial cells (A549)

Fine particulate matters-PM2.5 in the air can have considerable negative effects on human health and the environment. Various human cell-based studies examined the effect of PM2.5 on human health in different cities of the world using various chemical parameters. Unfortunately, limited information is available regarding the relationship between toxicity and chemical characteristics of PM2.5 collected in Istanbul, Türkiye, located in one of the most populated cities in the world. To investigate the chemical characteristics and cytotoxicity of PM2.5 in Istanbul, samples were collected for 12 months, then potentially toxic metals, oxidative potential, and particle indicators (e.g., functional groups and elements) were determined, and the cytotoxicity of PM2.5 on human A549 lung alveolar epithelial cells was examined. The mean PM2.5 mass concentration was 24.0 ± 17.4 µg m−3 and higher in cold months compared to other seasons. Moreover, the results of the metals, elemental, and functional groups indicated that seasonal and monthly characteristics were influenced by the regional anthropogenic sources and photochemistry input. The cytotoxicity results also showed that the viability of A549 cells was reduced with the exposure of PM2.5 (30–53%) and higher cytotoxicity was obtained in summer compared to the other seasons due to the impact of the metals, elements, and oxidative characteristics of PM2.5.

Characteristics of Fine Particulate Matter (PM2.5) Chemical Composition in the North Jakarta Industrial Area

Air pollution around industrial area has become a serious concern for both the public and local government. Thus, research on PM2.5 characterization is urgently needed. This study identifies the concentration and chemical characteristics of PM2.5 to provide an in-depth understanding of the composition of these particles around the largest industrial complex in North Jakarta. Sixty samples of PM2.5 were collected from residential sites around industrial areas in North Jakarta. Samples were collected on Teflon filters using a SuperSASS instrument during the period from February to July 2023, representing the wet and dry seasons. Mass concentrations of PM2.5, black carbon, and 19 chemical elements were determined. The average mass concentration of PM2.5 in the wet and dry seasons was 27.81±11.82 µg/m3 and 46.63±14.37 µg/m3, respectively. Although the concentration of PM2.5 was lower during the wet season, the concentrations of black carbon and certain elements did not decrease significantly. This shows that pollutants play an important role in both seasons in the study location. Sulfur is the most abundant element with the average concentration in the dry season (2,727.89 ng/m3) higher than in the wet season (1,983.18 ng/m3). The PM2.5 mass reconstruction results show that ammonium sulfate and black carbon have the largest portion of PM2.5 mass. The results are expected to be used as a scientific reference in studying air pollution problems in this region and assist in formulating air protection policies to reduce PM2.5 emissions.

Insights into PM2.5 pollution of four small and medium-sized cities in Chinese representative regions: Chemical compositions, sources and health risks

Fine particles (PM2.5) pollution is still a severe issue in some cities in China, where the chemical characteristics of PM2.5 remain unclear due to limited studies there. Herein, we focused on PM2.5 pollution in small and medium-sized cities in key urban agglomerations and conducted a comprehensive study on the PM2.5 chemical characteristics, sources, and health risks. In the autumn and winter of 2019–2020, PM2.5 samples were collected simultaneously in four small and medium-sized cities in four key regions: Dingzhou (Beijing-Tianjin-Hebei region), Weinan (Fenwei Plain region), Fukang (Northern Slope of the Tianshan Mountain region), and Bozhou (Yangtze River Delta region). The results showed that secondary inorganic ions (43.1 %–67.0 %) and organic matter (OM, 8.6 %–36.4 %) were the main components of PM2.5 in all the cities. Specifically, Fukang with the most severe PM2.5 pollution had the highest proportion of SO42− (31.2 %), while the dominant components in other cities were NO3− and OM. The Multilinear Engine 2 (ME2) analysis identified five sources of PM2.5 in these cities. Coal combustion contributed most to PM2.5 in Fukang, but secondary sources in other cities. Combined with chemical characteristics and ME2 analysis, it was preliminarily determined that the primary emission of coal combustion had an important contribution to high SO42− in Fukang. Potential source contribution function (PSCF) analysis results showed that regional transport played an important role in PM2.5 in Dingzhou, Weinan and Bozhou, while PM2.5 in Fukang was mainly affected by short-range transport from surrounding areas. Finally, the health risk assessment indicated Mn was the dominant contributor to the total non-carcinogenic risks and Cr had higher carcinogenic risks in all cities. The findings provide a scientific basis for formulating more effective abatement strategies for PM2.5 pollution.

Quantifying vehicle restriction related PM2.5 reduction using field observations in an isolated urban basin

Vehicle (related particulate matter) emissions, including primary vehicle (related particulate matter) emissions, secondary nitrate, and road dust, have become an important source of fine particulate matter (PM2.5) in many cities across the world. The relationship between vehicle emissions and PM2.5 during vehicle restrictions has not yet been revealed using field observational data. To address this issue, a three-month field campaign on physical and chemical characteristics of PM2.5 at hourly resolution was conducted in Lanzhou, an urban basin with a semi-arid climate. The Lanzhou municipal government implemented more strict vehicle restriction measure during the latter part of field campaign period. The concentration of nitrogen oxides (NO x ) and PM2.5 decreased by 15.6% and 10.6%, respectively during the strict vehicle restriction period. The daily traffic fluxes decreased by 11.8% due to the vehicle restriction measure. The vehicle emission reduction led to a decrease of 2.43 μg·m−3 in PM2.5, including the decrease of primary vehicle emissions, secondary nitrate, and road dust. The contribution of vehicle emissions to PM2.5 decreased by 9.0% based on the results derived from a positive matrix factorization model. The sources other than vehicle emissions increased by 0.2 μg·m−3. Combining all evidence from the observations, the reduction of vehicle emissions is almost equal to the observed reduction in PM2.5. A further extrapolation that 9.0% reduction in vehicle emissions led to the observed reduction in PM2.5 (2.32 μg·m−3). This study clearly quantifies the vehicle restriction related PM2.5 reduction using field observations. The results provide scientific support for the implementation of effective vehicle emission reduction measures.

A comprehensive SERS, SEM and EDX study of individual atmospheric PM2.5 particles in Chengdu, China

Characterization of atmospheric fine particulate matter (PM2.5) in large cities has important implications for the study of their sources and formation mechanisms, as well as in developing effective measures to control air pollution. Herein, we report a holistic physical and chemical characterization of PM2.5 by combining surface-enhanced Raman scattering (SERS) with scanning electron microscopy (SEM) and electron-induced X-ray spectroscopy (EDX). PM2.5 particles were collected in a suburban area of Chengdu, a large city in China with a population over 21 million. A special SERS chip composed of inverted hollow Au cone (IHAC) arrays was designed and fabricated to allow direct loading of PM2.5 particles. SERS and EDX were used to reveal the chemical composition, and particle morphologies were analyzed from SEM images. SERS data of atmospheric PM2.5 indicated qualitatively the presence of carbonaceous particulate matter, sulfate, nitrate, metal oxides and bioparticles. The EDX showed the presence of the elements C, N, O, Fe, Na, Mg, Al, Si, S, K, and Ca in the collected PM2.5. Morphology analysis showed that the particulates were mainly in the form of flocculent clusters, spherical, regular crystal shaped or irregularly shaped particles. Our chemical and physical analyses also revealed that the main sources of PM2.5 are automobile exhaust, secondary pollution caused by photochemical reactions in the air, dust, emission from nearby industrial exhaust, biological particles, other aggregated particles, and hygroscopic particles. SERS and SEM data collected during three different seasons showed that carbon-containing particles are the principal sources of PM2.5. Our study demonstrates that the SERS based technique, when combined with standard physicochemical characterization methods, is a powerful analytical tool to determine the sources of ambient PM2.5 pollution. Results obtained in this work may be valuable to the prevention and control of PM2.5 pollution in air.

Chemical characterization of PM10 and PM2.5 combusted firecracker particles during Diwali of Lucknow City, India: air-quality deterioration and health implications.

Urban air pollution is a growing menace leading to human discomfort, increased hospitalizations, morbidity, and mortality. This study deals with deteriorated air quality due to firecracker bursting during Diwali in Lucknow. Inhalable particulates and gaseous pollutants were monitored during Diwali 2020 using air samplers. Elements, ions, and surface morphology of particles were analyzed using ICP-MS, ion chromatograph, and SEM-EDX, respectively. PM10, PM2.5, SO2, and NO2 were 558, 352, 44, and 86 μg/m3 during Diwali night and 233, 101, 17, and 40 μg/m3 on pre-Diwali night while 241, 122, 24, and 43 μg/m3 on Diwali day. Concentrations surged for PM10: 139% and 132%, PM2.5: 249% and 189%, SO2: 159% and 83%, and NO2: 115% and 100% on Diwali night compared to pre-Diwali night and corresponding Diwali day, respectively. Al, K, Ba, and B showed dominance in PM10 whereas Zn, Al, Ba, and K in PM2.5 on Diwali night. The order of metal abundance in PM2.5 was Cd < Co < Ag < As < Cr < Ni < Cu < Bi < Pb < Mn < Sr < Fe < B < Zn < Al < Ba < K. Cations NH4+, K+, Mg2+, Ca2+, and anions F−, Cl−, NO3−, Br−, NO2−, SO4−2, PO43− showed a 2–8 fold increase on Diwali night relative to pre-Diwali night. Average metal concentrations varied by 2.2, 1.6, and 0.09 times on Diwali than pre-Diwali in residential, commercial, and industrial areas, respectively. PM10 concentration increased by 458% and 1140% while PM2.5, 487%, and 2247% than respective NAAQS and WHO standards. Tiny firecracker particles vary in toxicity as compared to vehicular emissions and have enhanced bioavailability leading to severe threat in terms of LRI, COPD, and atherosclerosis for city dwellers. It is imperative to recognize the present status of ambient air quality and implement regulatory strategies for emission reduction.Graphical abstract

Chemical characterization of PM2.5 in heavy polluted industrial zones in the Guanzhong Plain, northwest China: Determination of fingerprint source profiles

Industrial emission has been proved to be an important source of atmospheric PM2.5, which causes serious air pollution and health impacts. The air quality of the industrial zones, which are the intermediate stationary areas between the direct emissions and diffusion to the atmosphere, is always overlooked. In this study, the PM2.5 filter samples were collected in the six representative types of industrial zones in four cities of the Guanzhong Plain in 2020. The chemical characteristics of fine particulate matter (PM2.5) in the zones were investigated. The mass concentrations of 13 elements and 39 polycyclic aromatic hydrocarbons (PAHs) in PM2.5 were quantified. Cement and concrete (CC) and brick production (BP) exhibited a similar chemical composition profile characterized by high proportions of calcium (Ca), aluminum (Al), benzo[k]fluoranthene (BkF), 1-nitronaphthalene (1N-NAP), and 3-nitrofluoranthene (3N-FLA). Glassware and ceramics (GC) showed a distinguishable profile with a relatively low ratio of copper/cadmium (Cu/Cd) and lead (Pb)/Cd. The profile for metal forging (MF) was abundant in vanadium (V), Pb, indeno[1,2,3-cd]pyrene (IcdP) and also recognized by particular diagnostic ratios of nitrated-PAHs (n-PAHs). The highest proportions of several metals such as chromium (Cr), manganese (Mn), iron (Fe), nickel (Ni), zinc (Zn), Cd, and fluoranthene (FLA) were found in the thermoelectric industry (TI) due to a large amount of coal consumption in the manufacture processing. Chemical production (CP) was the only industrial type using natural gas as the main fuel in this study, which shows the distinguishing feature of relatively high proportions of low molecular weight parent-PAHs (p-PAHs) and 2-ring oxygenated-PAHs (o-PAHs). This study not only attains the detailed chemical fingerprints, but also the potential tracers and ratios, which are of great significance for refining source apportionment and relieving PM2.5 pollution contributed by the industrial sources.

On the varied emission fingerprints of particulate matter over typical locations of NCR (Delhi) – A perspective for mitigation plans

Source apportionment study of PM2.5 using positive matrix factorization was performed to identify the emission characteristic from different sectors (sub-urban residential, industrial and rapidly urbanizing) of Delhi during winter. Chemical characterization of PM2.5 included metals (Ca, Cd, Cr, Cu, Fe, K, Mg, Mn, Na, Ni, Pb and Zn), water soluble ionic compounds (WSICs) (Cl−, NO3−, SO42− and NH4+) and Carbon partitions (OC, EC). Particulates (PM2.5) were collected on filter twice daily for stable and unstable atmospheric conditions, at the locations with specific characteristics, viz. Ayanagar, Noida and Okhla. Ions solely occupied 50% of the total PM2.5 concentration. Irrespective of location, high correlation between OC and EC (0.871–0.891) at p ≤ 0.1 is observed. Relatively lower ratio of NO3/SO4 at Ayanagar (0.696) and Okhla (0.84) denotes predominance of emission from stationary sources rather than mobile sources like that observed at Noida (1.038). Using EPA PMF5.0, optimum factors for each location are fixed based on error estimation (EE). Crustal dust, vehicular emission, biomass burning and secondary aerosol are the major contributing sources in all the three locations. Incineration contributes about 19% at Ayanagar and 18% at Okhla. Metal industries in Okhla contribute about 19% to PM2.5. These specific local emissions with considerable potency are to be targeted for long-term policymaking. Considerable secondary aerosol contribution (15%–24%) indicates that gaseous emissions also need to be reduced to improve air quality.

Source Analysis of Ambient PM2.5 in Wuhan City Based on Random Forest Model

Based on the online monitoring data of fine particle(PM2.5) mass concentration, carbonaceous components, ionic constituents, and elemental components in an urban site of Wuhan from December 2019 to November 2020, the chemical characteristics of PM2.5 were analyzed. In addition, seasonal source apportionment of PM2.5 was conducted using the principal component analysis(PCA) method and random forest(RF) algorithm model. The results indicated that ρ(PM2.5) was the highest in winter[(61.33±35.32) μg·m-3] and the lowest in summer[(17.87±10.06) μg·m-3]. Furthermore, organic carbon(OC), with a concentration of(7.27±3.51) μg·m-3, accounted for the major proportion compared with that of elemental carbon(EC) in the carbonaceous component of PM2.5. NO3-, SO42-, and NH4+ had the highest proportion in ionic components, with concentrations of (11.55±3.86),(7.55±1.53), and (7.34±1.99) μg·m-3, respectively. K, Fe, and Ca were the main elements in elemental components, with concentrations of (752.80±183.98),(542.34±142.55), and (459.70±141.99) ng·m-3, respectively. Relying on main factor extraction by PCA and quantitative analysis by RF, five emission sources were ultimately confirmed. The seasonal concentration distribution of these emission sources was as follows:coal burning and secondary sources(46%, 39%, 41%, and 52% for spring, summer, autumn, and winter, respectively) made the highest contribution to PM2.5, followed by vehicle emission sources(22%, 28%, 27%, and 21%), industrial emission sources (14%, 18%, 17%, and 13%), dust sources (10%, 8%, 6%, and 6%), and biomass burning sources (8%, 7%, 9%, and 8%). The valuation of the RF model was evaluated using multiple indicators, including RMSE, MSE, and R2. The evaluation results showed that the model for winter had the best performance (R2=0.974, RMSE=3.795 μg·m-3, MAE=2.801 μg·m-3), the models for spring (R2=0.936, RMSE=3.512 μg·m-3, MAE=2.503 μg·m-3) and autumn (R2=0.937, RMSE=4.114 μg·m-3, MAE=3.034 μg·m-3) performed with moderate-fitting goodness, and the summer model showed a relatively weak-fitting performance (R2=0.866, RMSE=5.665 μg·m-3, MAE=3.889 μg·m-3). The RF model had a satisfactory performance in PM2.5 source apportionment and had excellent prospects in analyzing massive historical data of air pollutants.

Chemical characteristics of PM2.5 during spring and fall at two sites in Chungcheongnam-do, South Korea; insight into Fe solubility and SO42− formation

24-hr integrated PM2.5 were measured at two sites (Seosan and Asan) in Chungcheongnam-do, South Korea, during both spring and fall, with the following three objectives; i) to investigate the major chemical components driving PM2.5 pollution episodes and their formation processes, ii) to identify possible factors controlling aerosol Fe solubility, and iii) to examine the causes of high SO2 and SO42− measured at Asan site. The Seosan site is a place where the city, countryside, and agricultural and industrial complexes are mixed, and the Asan site is a place in which the city and industrial complexes are mixed.PM2.5 pollution episodes (>24-hr Korean PM2.5 of 35 μg/m3) during spring were dominated by local pollution, while during fall they were influenced by regional transport and local pollution. The major chemical components driving spring PM2.5 pollution episodes were NO3− for Seosan and SO42− and NO3− for Asan. On the other hand, in the fall, the increases in concentration of NO3− at both sites resulted in PM2.5 pollution episodes. During the spring and fall pollution episodes, favorable weather conditions such as low wind speed and high RH were likely an important factor for the enhanced formation of secondary inorganic aerosols. The difference in driving chemical composition leading to high PM2.5 between the two sites during pollution periods suggests that the formulation of a different control strategy is required to reduce PM2.5 concentrations at each site.Fe solubility (soluble Fe/total Fe) at Seosan and Asan were 6.2% and 5.9%, respectively, during spring, and they were 2.6% and 2.5%, respectively, during fall. Fe solubility was also enhanced during pollution episodes at both sites. The high correlations (R = 0.74–0.77) between Fe solubility and aerosol acidification [(SO42− + NO3−)/Fe] at both sites during the two seasons indicate that secondary acidic aerosol particles played a potential role in enhancing the solubility of Fe. However, Fe solubility during spring was more influenced by the acidification by SO42− particles than that by NO3− particles. Meanwhile, the opposite result was obtained for the Fe solubility during fall.The substantially increased SO42− concentration measured at the Asan site during spring was strongly associated with high SO2 emissions (∼45 ppb) from the upwind local source region and could be due to both the photochemical reaction in the afternoon and the aqueous-phase reaction between the evening and early morning hours. The results of this study suggest that reductions in SO2 and NOx emissions from local sources at the study region are absolutely required to reduce PM2.5 pollution episodes.

Diurnal Variation of Chemical Characteristics and Source Identification of Fine Particles in the Kaohsiung Harbor

This study investigated the diurnal and monthly variation of fine particle (PM2.5) concentrations and its chemical characteristics and source identification in the Kaohsiung Harbor. Three sites located in the harbor areas were selected for simultaneously sampling 12-h PM2.5 in four months with consecutive seven days in each month. Water-soluble ions (WSIs), metallic elements, carbons, anhydrosugars, and organic acids in PM2.5 were analyzed to characterize their chemical fingerprints and monthly variation. Field sampling and chemical analysis of PM2.5 showed that significant diurnal and monthly variations of PM2.5’s mass concentration and chemical composition were observed in the Kaohsiung Harbor. Prevailing wind direction highly influences the mass concentrations and chemical characteristics of PM2.5 in the port areas. PM2.5 was dominated by WSIs with the abundance of secondary inorganic aerosols (SIAs). Crustal elements dominated the metallic content of PM2.5, but trace elements mainly originated from anthropogenic sources. The V/Ni ratios of PM2.5 in the Kaohsiung Harbor were generally higher than 2.0. Organic carbon (OC) was superior to elemental carbon (EC) in PM2.5 with the dominance of secondary OC (SOC). High concentration of levoglucosan (levo) was observed in spring due to nearby biomass burning. Additionally, high mass ratios of malonic and succinic acids (M/S) in PM2.5 indicated the potential formation of SOAs. Results obtained from chemical mass balanced (CMB) receptor modeling showed that the major sources of PM2.5 resolved in the Kaohsiung Harbor were mobile sources, ship emissions and oil-fired boilers, steel plants, secondary aerosols, sea salt spray, and fugitive dust. Primary PM2.5 emitted from ship traffics accounted for 20.8% of PM2.5.

Transport route-based cluster analysis of chemical fingerprints and source origins of marine fine particles (PM2.5) in South China Sea

The fingerprints and source origins of marine PM2.5 at two background islands in the South China Sea were clustered via trajectory analysis and positive matrix factorization. High PM2.5 concentrations at the Dongsha Islands occurred for the north routes, while Nansha Islands had similar PM2.5 concentrations amongst the transport routes. However, the chemical characteristics of PM2.5 varied with the transport routes. Secondary inorganic aerosols (NO3-, SO42-, and NH4+) were abundant in water-soluble ions which dominated PM2.5. Crustal metals were the abundant metals in PM2.5, while trace metals were primarily originated from man-made sources. Organic carbon was superior to elemental carbon, and high concentrations of levoglucosan and organic acids were observed for the north routes. Overall, marine PM2.5 at the Dongsha Islands was highly influenced by long-range transport of Asian continental outflows, while particulate air quality at the Nansha Islands was mainly governed by clean air parcels blown from the SCS.

Chemical characterization of PM2.5 from region highly impacted by hailstorms in South America.

The chemical composition of particulate material plays an important role in the atmosphere, providing cloud and ice nuclei for storm development. This study aims to evaluate and infer the sources of ions, metals, and metalloids in the fine atmospheric particulate matter (PM2.5) from triple border Paraná, Santa Catarina (Brazil), and northeastern Argentina, which is among those with the highest hail incidence in the world. Among the ions, the concentrations presented the following sequence in decreasing order: [Formula: see text]> K+> [Formula: see text]> [Formula: see text]> Ca2+> Cl-> Na+> Mg2+. Regarding the metals and metalloid concentrations, the order was of S > Si > Al > Fe > P > Ti, Cr, Cu, and Zn > Br > Mn, and Ni. The main sources, supported by positive matrix factorization results, are soil and agricultural activities, as well as vehicular emissions due to the agricultural machinery and the displacement of residents. Besides, the influence of aerosols frombiomass burning and industrial activitieswas observed, possibly comefrom long-distance transport. The composition of PM2.5 presents one or more elements considered present ice nuclei (IN)activity, such as Al, Mn, Cu, Co, Ni, and V (inform of oxides), corroborating with other studies, also, with high hail incidence. However, further studies are needed to verify the role of aerosol characteristics in the formation of IN and, consequently, hail.

Influence of pollution reduction interventions on atmospheric PM2.5: A case study from the 2017 Xiamen

To investigate the influence of pollution control on particulate matter with a diameter ≤2.5 μm (PM2.5), 40 samples were collected before and during the 2017 BRICS summit (BRICS) in an urban and a suburban area of the city of Xiamen, China. The average urban and suburban area PM2.5 concentrations during the BRICS were 26.3% and 35.9% lower than those before the summit, respectively. Chemical characteristics of PM2.5, such as water-soluble ions (WSIIs), organic and elemental carbon (OC and EC), macro elements and trace elements (inorganic elements), were measured. WSIIs and organic matter accounted for the highest proportions in PM2.5. During the BRICS, concentrations of WSIIs, OC, EC and inorganic elements decreased by 17.6%, 39.0%, 42.9%, 44.1% in urban areas and decreased by 0.9%, 35.1%, 53.8%, 79.4% in suburban areas. The influence of primary sources on WSIIs and carbon aerosol decreased and secondary formation increased. High O3 concentrations played an important role in the formation of secondary aerosols. However, the contribution of inorganic element sources did not noticeably change according to Pb–Sr-Nd isotope analysis. Pollution control during the BRICS was effective but not sufficient to reduce health risk from heavy metals in PM2.5, and carcinogenic risks from Cr, Cd, and As exceeded the safety value (10−6).

Inter-comparison of chemical characteristics and source apportionment of PM2.5 at two harbors in the Philippines and Taiwan

This study inter-compared the concentration and chemical characteristics of PM2.5 at two harbors in East Asia, and identified the potential sources of PM2.5 and their contribution. Two sites located at the Kaohsiung (Taiwan) and Manila (the Philippines) Harbors were selected for simultaneous sampling of PM2.5 in four seasons. The sampling of 24-h PM2.5 was conducted for continuous seven days in each season. Water-soluble ions, metallic elements, carbonaceous content, anhydrosugars, and organic acids in PM2.5 were analyzed to characterize their chemical fingerprints. Receptor modeling and trajectory simulation were further applied to resolve the source apportionment of PM2.5. The results indicated that the Kaohsiung Harbor was highly influenced by long-range transport (LRT) of polluted air masses from Northeast Asia, while the Manila Harbor was mainly influenced by local emissions. Secondary inorganic aerosols were the most abundant ions in PM2.5. Crustal elements dominated the metallic content of PM2.5, but trace elements were mainly originated from anthropogenic sources. Higher concentrations of organic carbon (OC) than elemental carbon (EC) was found in PM2.5, with secondary OC (SOC) dominant to the former. Levoglucosan in PM2.5 at the Manila Harbor were superior to those at the Kaohsiung Harbor due to biomass burning surrounding the Manila Harbor. Additionally, high mass ratios of malonic and succinic acids (M/S) in PM2.5 indicated the formation of SOAs. Overall, the ambient air quality of Manila Harbor was more polluted than Kaohsiung Harbor. The Kaohsiung Harbor was more severely affected by LRT of polluted air masses from Northeast Asia, while those toward the Manila Harbor came from the oceans. The major sources resolved by CMB and PMF models at the Kaohsiung Harbor were secondary aerosols, ironworks, incinerators, oceanic spray, and ship emissions, while those at the Manila Harbor were secondary aerosols, soil dust, biomass burning, ship emissions, and oceanic spray.

Mass Concentration, Chemical Composition, and Source Characteristics of PM2.5 in a Plateau Slope City in Southwest China

In order to investigate the seasonal variations in the chemical characteristics of PM2.5 at the plateau slope of a mountain city in southwest China, 178 PM2.5 filters (89 quartz and 89 Teflon samples for PM2.5) were collected to sample the urban air of Wenshan in spring and autumn 2016 at three sites. The mass concentrations, water-soluble inorganic ions, organic and inorganic carbon concentrations, and inorganic elements constituting PM2.5 were determined, principal component analysis was used to identify potential sources of PM2.5, and the backward trajectory model was used to calculate the contribution of the long-distance transmission of air particles to the Wenshan area. The average concentration of PM2.5 in spring and autumn was 44.85 ± 10.99 μg/m3. Secondary inorganic aerosols contributed 21.82% and 16.50% of the total PM2.5 in spring and autumn, respectively. The daily mean value of OC/EC indicated that the measured SOC content was generated by the photochemical processes active during the sampling days. However, elements from anthropogenic sources (Ti, Si, Ca, Fe, Al, K, Mg, Na, Sb, Zn, P, Pb, Mn, As and Cu) accounted for 99.38% and 99.24% of the total inorganic elements in spring and autumn, respectively. Finally, source apportionment showed that SIA, dust, industry, biomass burning, motor vehicle emissions and copper smelting emissions constituted the major components in Wenshan. This study is the first to investigate the chemical characterizations and sources of PM2.5 in Wenshan, and it provides effective support for local governments formulating air pollution control policies.

Chemical Characteristics and Sources of Water-Soluble Organic Nitrogen Species in PM2.5 in Nanjing, China

Water-soluble organic nitrogen (WSON) is an important component of PM2.5 which may affect air quality, climate and human health. Herein, one-year field samples of atmospheric PM2.5 (June 2017–May 2018) were collected in northern Nanjing. Chemical characterization of PM2.5 major components as well as WSON were conducted, and WSON composition and sources were further investigated via measurements by a Aerodyne soot particle aerosol mass spectrometer (SP-AMS) as well as positive matrix factorization (PMF). Inorganic ions, mainly consisting of ammonium, sulfate, and nitrate, were found to dominate PM2.5 mass (58.7%), followed by organic matter (OM) (22.6%), and elemental carbon (EC) (2.1%). Water-soluble OM dominated OM (65.1%), and its temporal variation was closely correlated with that of secondary organic matter, while time series of water-insoluble OM concentrations correlated tightly with that of primary organic matter. Average WSON concentration was 2.15 μg/m3, which was highest in winter and lowest in summer. Correlation analysis of WSON with PM2.5 components also indicated that WSON was mainly from secondary sources. SP-AMS revealed that WSON mass spectrum was composed of CxHyNp+ (91.2%) and CxHyOzNp+ (8.8%), indicating dominance of amines and other oxygenated ON compounds. PMF analysis resolved two primary sources (traffic, biomass burning) and two secondary sources (less-oxidized and more-oxidized factors) of WSOM and WSON, and the secondary source dominated both WSOM and WSON. Contribution of the more-oxidized ON factor was very high in winter, and the less-oxidized factor was significant in summer, indicating a likely important role of aqueous-phase processing in winter as well as photochemical oxidation in summer to WSON.

Chemical characterization of PM2.5 emitted from China IV and China V light-duty vehicles in China

This study reported the emission factors (EFs) and detailed chemical compositions of PM2.5 collected from China IV and China V light-duty vehicles (LDVs) through dynamometer test. The China IV LDVs containing 4 gasoline vehicles (GVs) and 4 natural gas vehicles (NGVs) had port fuel injection (PFI) engines, while the China V LDVs included 2 GVs with PFI engines and 2 GVs with gasoline direct injection (GDI) engines. The average EFs of PM2.5 were 1.90 ± 0.70 mg km−1, 1.44 ± 0.29 mg km−1, and 0.56 ± 0.05 mg km−1 for China IV GVs, China IV NGVs, and China V GVs, respectively. PM2.5 profiles of LDVs were characterized by abundant carbon species (60.59–68.58%) with low amounts of water soluble ions (WSIs, 6.96–16.37%) and elements (5.20–7.53%). In general, the EFs of PM2.5 constituents including organic carbon (OC), elemental carbon (EC), WSIs, and elements were reduced obviously by strengthening emission standards from China IV to China V. While the contributions of most WSIs and elements to PM2.5 increased as vehicle technology improved. Furthermore, the EFs of PM2.5 components from China IV LDVs also decreased when shifting fuels from gasoline to natural gas. While the fractions of OC, WSIs and most elements in PM2.5 increased due to the highest reduction rate of EC mass. For China V LDVs, GDI vehicles emitted less OC but more EC compared to PFI vehicles, and the EFs of most WSIs and elements also increased. Overall, GDI vehicles exhibited lower fractions OC and WSIs but higher contents of EC and elements in PM2.5. Besides, PM2.5 and its chemical species were heavily dependent on vehicle's driving patterns. The average EFs of PM2.5 components under aggressive driving pattern increased significantly compared to those under moderate driving pattern.

Assessment of long-range oriented source and oxidative potential on the South-west shoreline, Korea: Molecular marker receptor models during shipborne measurements

In order to determine the quantitative contributions of PM2.5 on the South-west shoreline of Korea, filter based samplings were conducted in the summertime of 2017 and 2018 (total 32 days) via shipborne measurements using both a high volume and middle volume air sampler. Water-soluble organic carbon, water-soluble ions, organic carbon and elemental carbon, elemental species, and organic molecular markers by Liquid Chromatography–tandem Mass Spectrometry were utilized to characterize the collected substrates. The current study investigates the (1) chemical characteristics of PM2.5, (2) source apportionment using positive matrix factorization (PMF), and (3) relationship between sources and the dithiothreitol (DTT) assay during the two sampling periods. A mean PM2.5 concentration of 19.3 μg/m3 was observed along the entire sampling route. The ratio of water-soluble to organic carbon implies that secondary aerosol formation is dominant. The result of methanesulfonic acid (MSA) suggests the contribution of a marine-oriented biogenic source of PM2.5. The PMF source apportionment model showed six source categories with reasonably stable profiles: 1) sulfate-rich, 2) MSA-rich, 3) nitrate-rich, 4) secondary organic, 5) continental, and 6) biomass burning sources. The PMF showed three strong events (i.e., long-range transport, mixed (ocean and long-range stay), and domestic origin events) in the contributions of sources, as well as a dependence on wind transport. Higher associations with DTT oxidative potential normalized to PM2.5 mass concentration (DTT–OPm) related to long-range transport, hence, confirming the impacts of the highest intrinsic oxidative potential.