[Spatial Variability and Source Apportionment of PM2.5 Carbon Components in Tianjin]

The contents of eight carbonaceous subfractions were determined by simultaneously collecting PM2.5 samples from four sites in different functional areas of Tianjin in 2021. The results showed that the organic carbon (OC) concentration was 3.7 μg·m-3 to 4.4 μg·m-3, and the elemental carbon (EC) concentration was 1.6 μg·m-3 to 1.7 μg·m-3, with the highest OC concentration in the central urban area. There was no significant difference in EC concentration. The concentration of PM2.5 showed the distribution characteristics of the surrounding city>central city>peripheral area. The OC/EC minimum ratio method was used to estimate the concentrations of secondary organic carbon (SOC) in PM2.5, and the results showed that the secondary pollution was more prominent in the surrounding city, with SOC accounting for 48.8%. The correlation between carbon subcomponents in each functional area showed the characteristics of the peripheral area>central area>surrounding area, all showing the strongest correlation between EC1 and OC2 and EC1 and OC4. By including the carbon component concentration into the positive definite matrix factorization (PMF) model for source apportionment, the results showed that road dust sources(9.7%-23.5%), coal-combustion sources (10.2%-13.3%), diesel vehicle exhaust (12.6%-20.2%)and gasoline vehicle exhaust (18.9%-38.8%)were the main sources of carbon components in PM2.5 in Tianjin. The pollution sources of carbon components were different in different functional areas, with the central city and peripheral areas mainly affected by gasoline vehicle exhaust; the surrounding city was more prominently affected by the secondary pollution and diesel vehicle exhaust.

[Health Impacts of Air Pollution in Tianjin]

Ambient air pollution is a dominant determinant of health. The health effects and economic losses due to air pollution are very important for decision-making. Since the implementation of the "Air Pollution Prevention and Control Action Plan" and "blue sky defense war" policies, the air quality of Tianjin has changed significantly. Here, the health effects and economic losses attributable to ambient air pollution in Tianjin from 2013 to 2020 wereestimated. For the particulate matter which has complex components, we assessed the inhalation health risks of heavy metals and polycyclic aromatic hydrocarbons (PAHs) in PM_2.5. The variation in the concentration of the main components of PM_2.5 was also analyzed. The results showed that improved air quality had positive health benefits. The health benefits from SO₂ were the highest among the six air pollutants, and 3786 deaths were avoided in 2020 compared to in 2013 due to lower SO₂ concentration. The economic losses caused by air pollutants ranged from several billion to ten billion yuan. Among the six air pollutants, particulate matter and ozone had higher health losses in recent years. The health risks of heavy metals and PAHs in PM_2.5 showed a decreasing trend. However, Cr(Ⅵ), As, Cd, and Ni in PM_2.5in the winter of 2020 still had respiratorysystem carcinogenic risk, whereas there was no health risk of PAHs in PM_2.5in 2019-2020. The concentrations of main components of PM_2.5 have decreased significantly. In the future, the reduction of health loss caused by air pollution depends on synergy governance of particulate matter and ozone and further research on health effects.

[Spatial-temporal Variation and Driving Factors of Ozone in China from 2019 to 2021 Based on EOF Technique and KZ Filter]

Based on the hourly O₃ concentration data of 337 prefectural-level divisions and simultaneous surface meteorological data in China, we applied empirical orthogonal function (EOF) analysis to analyze the main spatial patterns, variation trends, and main meteorological driving factors of O₃ concentration in China from March to August in 2019-2021. In this study, a KZ (Kolmogorov-Zurbenko) filter was used to decompose the time series of O₃ concentration and simultaneous meteorological factors into corresponding short-term, seasonal, and long-term components in 31 provincial capitals.Then, the stepwise regression was used to establish the relationship between O₃ and meteorological factors. Ultimately, the long-term component of O₃ concentration after "meteorological adjustment" was reconstructed. The results indicated that the first spatial patterns of O₃ concentration showed a convergent change, that is, the volatility of O₃ concentration was weakened in the high-value region of variability and enhanced in the low-value region.Before and after the meteorological adjustment, the variation trend of O₃ concentration in different cities was different to some extent. The adjusted curve was "flatter" in most cities. Among them, Fuzhou, Haikou, Changsha, Taiyuan, Harbin, and Urumqi were greatly affected by emissions. Shijiazhuang, Jinan, and Guangzhou were greatly affected by meteorological conditions. Beijing, Tianjin, Changchun, and Kunming were greatly affected by emissions and meteorological conditions.

[Main Problems and Refined Solutions of Urban Fugitive Dust Pollution in China]

Fugitive dust poses an important contribution to urban air particulate matter in China. To further improve the level of dust pollution prevention and control, the emission and contribution characteristics of urban fugitive dust were summarized; the main causes of dust pollution were analyzed; and the key links, key indicators, and main measures for prevention and control were clarified, so as to further improve the concept of "accurate dust control." Among all types of fugitive dust sources, road dust and construction dust were the main emission and contribution sources, among which road dust was more prominent. Production activities, vehicle disturbances, and wind erosion were the main dust-generating links of various dust sources. Silt loading was taken as the key control index for road dust prevention and control, whereas silt loading and bare soil (or material) areas were taken as the key control index for construction and other dust sources. Around the key indicators, three main ways to control the road dust and six main measures to control the construction and other dust sources were defined. In addition, some suggestions on the necessary supporting measures for dust control were put forward, so as to provide a comprehensive and beneficial reference for the practical application of dust control in Chinese cities.

[PM2.5 Source Apportionment Based on a Variety of New Receptor Models]

In order to understand the applicability of various new receptor models, four receptor models, including the positive matrix factorization/multilinear engine 2-species ratio (PMF/ME2-SR), partial target transformation-positive matrix factorization (PTT-PMF), positive matrix factorization (PMF), and chemical mass balance (CMB), were used to analyze and verify the atmospheric fine particulate matter (PM_2.5) data of a typical city in northern China. It was found that coal combustion (25%-26%), dust (19%-21%), secondary nitrate (17%-19%), secondary sulfate (16%), vehicle emissions (13%-15%), biomass burning (4%-7%), and steel (1%-2%) had a contribution to PM_2.5. By comparing the source profiles and source contributions obtained by different models and calculating the coefficient of differences (CD) and average absolute error (AAE) of each source, we found that although the source apportionment results of the four models were in good agreement (the average CD value was between 0.6 and 0.7), there were still slight differences in the identification of some components in each source. Compared with the traditional model (PMF), the PMF/ME2-SR model can better identify sources with similar source profile characteristics, which is due to the component ratios of sources that are introduced. For example, the CD and AAE of dust sources were 15% and 54% lower than those of PMF, respectively. The PTT-PMF model takes the measured primary source profiles and virtual secondary source profiles as a constraint target, and the calculated CD and AAE of secondary sulfate were 0.25 and 17%, respectively, which were 55% and 23% lower than PMF. The PTT-PMF model can obtain more "pure" secondary sources and identify the pollution sources that are not identified by other models, which has more advantages in the refined identification of sources.

[Emission Performance Quantitative Evaluation and Application of Industrial Air Pollution Sources]

Treatment of industrial atmospheric emission sources is an important way to improve air quality, but accurate pollution control remains still an urgent challenge. Taking Xiqing District of Tianjin as an example, based on the second national pollution source census, this study carried out a quantitative evaluation of the pollutant emission performance of industrial enterprises and explored the significance, feasibility, and challenges facing emission performance evaluation. The results show that the emission performance of various industries in Xiqing District vary greatly. The pollutant emission performance level is closely related to an industry's own attributes, development scale, and management level. On the whole, the emission performance level of industries with high production process emission coefficients and a high proportion of small and medium-sized enterprises (such as furniture manufacturing, the metal products industry, ferrous metal smelting, and the rolling processing industry) is worse, while the emission performance of high-end industries represented by computer communication and other electronic equipment manufacturing and automobile manufacturing is generally better. The emission performance of different enterprises in the same industry also varies greatly. For example, the 11 enterprises with the worst performance in the metal machinery manufacturing industry only contributed 0.06% of industrial output yet their PM emission contribution reached 8.50%. The 19 worst-performing enterprises in the rubber and plastic industry contributed 4.76% of industrial output yet their VOCs emissions accounted for 43.59% of the total. At the same time, this study presents an emissions reduction plan according to the relevant technical guidelines of the Ministry of Ecology and Environment. Based on this, the cost of emissions reduction could be cut by as much as 90% when the pollutant emissions reductions of the same scale are reduced. The gap in the pollutant emissions performance of various industries and enterprises, the incongruity between economic benefits and environmental costs, and the important guiding role of emission performance evaluation for emissions reductions demonstrate the necessity of performance evaluation. Overall, this research shows that pollutant emission performance evaluation can effectively support macro-industrial structure adjustment and the environmental governance of meso-micro industrial enterprises, providing an important reference for pollution control interventions.

Production of metallic ion beams by electron cyclotron resonance ion sources equipped with inductive heating ovens at the Institute of Modern Physics

A high-temperature oven based on the inductive heating technology was developed successfully at the Institute of Modern Physics in 2019. This oven features a durable operation temperature of over 2000 °C inside the tantalum susceptor. By carefully designing the oven structure, the material compatibility issue at high temperature has been successfully solved, which enables the production and routine operation of refractory metal ions with SECRAL-II (Superconducting Electron Cyclotron Resonance ion source with Advanced design in Lanzhou No. 2). To further apply this type of oven to the room temperature ECR ion sources LECR4 and LECR5 (Lanzhou Electron Cyclotron Resonance ion source No. 4 and 5), a mini-inductive heating oven has been fabricated and tested in 2020. By directly evaporating calcium oxide, some high charge state calcium beams have been produced successfully, such as 52 euA of ⁴⁰Ca¹⁶⁺, 30 euA of ⁴⁰Ca¹⁷⁺, and 12 euA of ⁴⁰Ca¹⁸⁺. The detailed design and testing results will be presented and discussed.

[Size Distribution of Aerosol Hygroscopic Growth Factors in Winter in Tianjin]

Aerosol hygroscopic growth factors[g(RH)] are key for evaluating aerosol light extinction and direct radiative forcing. The hygroscopic tandem differential mobility analyzer (HTDMA) was utilized to measure the size-resolved g_m(RH) under different polluted conditions in winter in Tianjin. Furthermore, based on the size distribution of aerosol water-soluble ions, the g_κ(RH) across a wide size range (60 nm to 9.8 μm) was estimated using the κ-Köhler theory, which provides a basis for the estimation of aerosol optical parameters and direct radiative forcing under ambient conditions. Under clean conditions, ultrafine particles (<100 nm) were more hygroscopic and g_m(RH=80%) was higher than 1.30 due to the active photolysis reaction. However, under severely polluted conditions, the proportion of water-soluble ions in aerosols increased with the increasing size; g_m(RH) increased with particle size, where g_m(RH=80%) and g_m(RH=85%) for 300 nm particles was 1.39 and 1.46, respectively. For a wide size range (60 nm to 9.8 μm), the aerosols in the accumulation mode were more hygroscopic and aerosols in the Aitken mode were less hygroscopic, with coarse mode aerosols being the least hygroscopic. During the polluted period, the particulate size notably increased, and the mass fraction of NO₃^- and SO₄^2- in the accumulation mode aerosols was significantly higher than during the clean period. Accordingly, the hygroscopicity of accumulation mode aerosols was strongly enhanced during the polluted period[g_κ(RH)=1.3-1.4] and aerosols in the 0.18-3.1 μm size range all had a strong hygroscopicity. On polluted days, the synergistic effect of the increase in particle size, water-soluble ions, and aerosol hygroscopicity results in the considerable deterioration of visibility.

[Characteristics of Ozone and Source Apportionment of the Precursor VOCs in Tianjin Suburbs in Summer]

From June to August 2018, a 1-hr resolution concentration dataset of ozone and its gaseous precursors (volatile organic compounds(VOCs) and NO_x), and meteorological parameters were synchronously monitored by online instruments of the Nankai University Air Quality Research Supersite. The relationships and variation characteristics between ozone and its precursors were analyzed. According to the photochemical age, the initial concentrations of VOCs were calculated, and the photochemical loss of the concentration of VOCs during the daytime (06:00-24:00) was corrected. The initial and directly monitored concentrations of VOCs were incorporated into the PMF model for source apportionment. The results indicated that the mean concentration of O₃ in Tianjin in summer was (41.3±25.7)×10^-9, while that of VOCs was (13.9±12.3)×10^-9. The average concentration of alkane (7.0±6.8)×10^-9 was clearly higher than that of other VOC species. The species with high concentrations of alkanes were propane and ethane, accounting for 47% of the total alkane concentration. The average ozone formation potential (OFP) in summer was 52.1×10^-9, and the OFP value of alkene was the highest and its contribution reached 57%. During the daytime, alkene loss accounted for 75% of the total VOC loss. The major sources of VOCs that were calculated based on the initial concentration data were the chemical industry and solvent usage (25%), automobile exhaust (22%), combustion source (19%), LPG/NG (19%), and gasoline volatilization (15%), respectively. Compared with the apportionment results based on directly monitored concentrations, the contribution of the chemical industry and solvent usage decreased by 4%, while automobile exhaust decreased by 5%. By combining the results of PMF apportionment and the OFP model to analyze the relative contributions of emission sources to ozone formation, and we found that the highest contribution source of ozone was the chemical industry and solvent usage (26%) in summer. Compared with the analysis results based on the directly monitored concentrations, the OFP values of the chemical industry and solvent usage decreased by 7%, while that of NG/LPG apparently decreased by 13%.

[Influence of Typical Desulfurization Process on Flue Gas Particulate Matter of Coal-fired Boilers]

As flue gas desulfurization (FGD) was one of the most important purification processes of coal-fired boilers, we selected four boilers, which were equipped with wet limestone, furnace calcium injection, ammonia-based, and double-alkali FGDs, to research the influence of FGDs on the flue particulate matter (PM). The flue PM before and after the FGD were sampled using laboratory resuspension and dilution tunnel sampling methods, respectively, and the PM was analyzed for its chemical composition (i.e., ions, elements, and carbon). The results showed that the types of desulfurizers could influence the composition of the flue PM. After passing through the wet limestone, ammonia-based, and double-alkali FGDs, the proportion of Ca, NH₄⁺, and Na in PM_2.5 increased from 5.1% to 24.8%, from 0.8% to 7.3%, and from 0.9% to 1.7%, respectively. The influence of wet and dry FGDs on the flue PM were different. The fraction of ions in the PM emitted from the wet FGD were higher than those from the dry FGD. The proportion of SO₄^2- in the flue PM_2.5 increased from 2.0% and 6.7% to 9.6% and 11.9% using the wet limestone and ammonia-based FGDs, respectively, and Cl^- increased from 0.4% and 1.2% to 3.8% and 5.2%. In addition, the amount of heavy metals (e.g., Cr, Pb, Cu, Ti, and Mn) in PM_2.5 declined after the wet FGDs. The PM_2.5 emitted from the dry FGD boiler was richer in crustal elements, such as Al, Si, and Fe, than that from the wet FGDs. The wet FGDs also effected the carbonaceous components of the flue PM. After passing through the wet limestone and ammonia-based FGDs, the proportion of elemental carbon in the flue PM_2.5 decreased from 6.1% to 0.9% and from 3.6% to 0.7% respectively, but the organic carbon content did not decrease.

[Evaluation of Different ISORROPIA-Ⅱ Modes and the Influencing Factors of Aerosol pH Based on Tianjin Online Data]

Aerosol acidity is closely related to particle properties and the explosive growth of secondary particles. Aerosol pH is difficult to measure directly but can be estimated indirectly by thermodynamic equilibrium modeling. ISORROPIA-Ⅱ is one of the most commonly used thermodynamic models and includes different modes (forward and reverse) and aerosol states (stable and metastable). Studies have shown that the calculated pH results vary with the selected mode and phase state. In addition to the selection of modes and phases, there are also other factors that influence the modeling results. In order to explore the appropriate mode and phase selection of ISORROPIA-Ⅱ as well as the factors influencing the model results under the air pollution characteristics of typical Chinese cities, the simulation results of different modes and aerosol states were analyzed by using online hourly data for Tianjin. The results showed that the pH calculations using the forward mode and metastable state were satisfactory at a higher RH. With increased temperature, the pH, aerosol water content, and concentration proportion in the aerosol phase of semi-volatile components all decreased. RH affected aerosol pH by influencing the aerosol water content and concentration of semi-volatile components. An increased cation concentration led to an increased pH and NH₃ concentration but a decreased HNO₃ concentration, whereas an increased anion concentration had the opposite effect. Ca²⁺, SO₄^2-, NO₃^-, and NH₄⁺ had a great influence on pH. Compared with SO₄^2-, NO₃^- had less effect on pH. Sensitive areas exist in the influence of NH₄⁺ on pH, and a high NH₄⁺ concentration did not cause a continuous pH increase. This study can improve the understanding of aerosol pH simulation using ISORROPIA-Ⅱ, and provides reference for research on the pH-related secondary generation mechanism, semi-volatile component gas-particle distribution, and pollution control measures.

Influence of electron cyclotron resonance ion source parameters on high energy electrons

In order to diagnose the electron cyclotron resonance (ECR) plasma, a high-efficiency collimation system has been developed at the Institute of Modern Physics, and the bremsstrahlung spectra in the range of 10 keV-300 keV were measured on a third generation superconducting ECR ion source, SECRAL-II, with a CdTe detector. Used as a comparative index of the mean energy of the high energy electron population, the spectral temperature, T_s, is derived through a linear fitting of the spectra in a semi-logarithmic representation. The influences of some main source parameters, such as the neutral gas pressure, extraction voltage, microwave power, and bias disk voltage, on the high energy electrons are systemically investigated.

[Mixed State and Sources of Fine Particulate Matter in the Summer in Tianjin City Based on Single Particle Aerosol Mass Spectrometer (SPAMS)]

Tianjin is located in the Beijing-Tianjin-Hebei region. Recently, particulate matter pollution has received wide attention; therefore, studying the chemical composition and sources of particulate matter in the atmospheric environment is of great significance. To clarify the mixed state and possible sources of particulate matter in the summer ambient air in Tianjin, this study used single particle aerosol mass spectrometer (SPAMS) to collect 209887 samples. Particle size and complete spectrometry information were collected in July 2017. A total of 369 particle classes were obtained with respect to clustering particles with similarities in mass spectrometry characteristics using ART-2a. Then, according to the similarity in the chemical composition (mass spectrometry) of the categories, 19 particulate matter categories were artificially merged: K-EC (0.20%), K-EC-Sec (0.18%), K-NO₃-PO₃(12.00%), K-NO₃-SiO₃(2.98%), K-Sec (0.16%), EC (39.60%), EC-Sec (3.46%), EC-HM-Sec (3.93%), HEC (1.49%), HEC-Sec (1.38%), OC-Amine-Sec (3.58%), OC-Sec (0.36%), OCEC-Sec (0.71%), Dust-HEC (21.35%), Dust-Sec (0.72%), Cl-EC-NO₃(1.22%), Na-Cl-NO₃(3.20%), HM-Sec (2.58%), and PAH-Sec (0.90%). The obtained particle classes can be attributed to different sources of aerosol particles and different transmission and reaction processes. According to comprehensive analysis, the collected particle contribution sources were found to mainly include motor vehicle emission sources, biomass combustion sources, process sources, dust sources, and secondary processes. Among them, K-EC, EC, HEC, and Dust-HEC particles were mainly from direct emissions of primary sources. K-Sec, OC-Amine-Sec, OC-Sec, OCEC-Sec, Na-Cl-NO₃, and PAH-Sec particles mainly undergo different degrees of aging or mixed with secondary components.

[Construction and Evaluation on Size Resolved Source Apportionment Methods Based on Particle Size Distribution of Chemical Species]

The analysis of the sources of atmospheric particulate pollution can provide scientific support for the prevention and control of air pollution. Most particulate matter (PM) source analysis studies are based on the chemical composition of PM. In addition, particle size characteristics are also one of the important properties of PM. The accuracy of analytical results can be improved by analyzing the particle size characteristics of chemical components. In this study we aim to to solve the problem of insufficient utilization of component particle size information by using a the three-dimensional multi-particle size factor analysis model (ABB), where the particle size distribution of marked components is regarded as the constraint limit, and a multi-particle size source analytical model (SDABB) based on the characteristics of the components particle size distribution is constructed. The sensitivity of the SDABB model to the collinearity of the source spectrum and the similarity of the particle size distribution of the source contributions are investigated by evaluating the model through the simulation of the data set. The results showed that the ABB model was sensitive to the collinearity of the source spectrum and to the similarity of the particle size distribution of the source contributions. When particle size distribution rules were incorporated into the SDABB model, the effects of the two scenarios were significantly improved, that is, the SDABB model was able to better analyze collinear source spectrum and was insensitive to the similarity of the contribution particle size distribution.

[PM2.5 Pollution Characteristics During Winter and Summer in the Hohhot-Baotou-Ordos Region, China]

Based on the source apportionment by positive matrix factorization (PMF) model, we analyze the main sources and characteristics of aerosol fine particulate matter (PM_2.5) during winter and summer in the Hohhot-Baotou-Ordos region, China. We found that organic (19.9%-44.6%) and crustal compositions (9.7%-46.2%) accounted for a large proportion of aerosol PM_2.5 according to the results of mass closure. The results of source apportionment showed that the contribution of sources rank as:secondary inorganic aerosol (26.7%) > coal (26.1%) > motor vehicle (19.1%) > dust (18.1%) during winter, and as:secondary inorganic aerosol (26.7%) > dust (22.3%) > coal (16.6%) > vehicle exhaust (15.1%) > SOC (8.7%) during summer. Findings suggest that the contribution of sources with secondary inorganic aerosol were the largest sources both in winter and summer, and that the Hohhot-Baotou-Ordos region was also affected by coal during the winter and dust during the summer. Corresponding to the source apportionment, analysis of typical heavy pollution episodes in winter and summer showed that the pollution sources during the winter were mainly secondary inorganic aerosol and coal, whereas they were mainly secondary inorganic aerosol during the summer.

A new microwave coupling scheme for high intensity highly charged ion beam production by high power 24-28 GHz SECRAL ion source

The efficiency of the microwave-plasma coupling is a key issue to enhance the performance of electron cyclotron resonance ion sources (ECRISs) in terms of higher ion beam intensity yield. The coupling properties are affected by the microwave coupling scheme, especially for the high frequency (f > 20 GHz) and high power (P > 5 kW) ECR ion sources. Based on the study of 24 GHz SECRAL ion source performances working at different launching systems, a new microwave coupling scheme, called the Vlasov launcher, is proposed, which can not only realize efficient power matching and feeding but also enhance the microwave power distribution on the ECR surface. The first promising results are presented in this article. Then, a prototype dedicated to the next generation ECRIS is described.

Comparison of size-resolved hygroscopic growth factors of urban aerosol by different methods in Tianjin during a haze episode

Size-resolved hygroscopic growth factors of urban aerosol during a haze episode were measured using a Humidified Tandem Differential Mobility Analyzer (HTDMA) (g_m(RH)). These factors were also derived from size-resolved particulate chemical composition combined with the κ-Köhler theory (g_κ(RH)) and the thermodynamic model ISORROPIA-II running in forward mode (g_iso-f(RH)) and reverse mode (g_iso-r(RH)), respectively. In terms of agreement among these hygroscopic growth factors, g_κ(RH) matched g_m(RH) best, followed by g_iso-r(RH). In contrast, g_iso-f(RH) demonstrated a poorer agreement with g_m(RH). The good consistency among g_m(RH), g_κ(RH), and g_iso-r(RH) was because they only focus on the physical hygroscopic process, whereas g_iso-f(RH) contains not only the direct influence of relative humidity (RH) on particle size but also the influence of gaseous precursor on the particle chemical composition, which indirectly affects the hygroscopicity of the particles. In this sense, size-resolved g_κ(RH) and g_iso-r(RH) in a wide size range are more adequate to investigate the impact of RH on light scattering and aerosol radiative forcing. At RH = 80%, g_κ(RH) for accumulation mode particles was 1.30-1.45 on polluted days and higher than that on clean days (1.2-1.3). Whereas on both polluted and clean days, g_κ(RH) of ultrafine and coarse mode particles were generally lower than 1.25. The strong hygroscopicity of accumulation mode particles observed on polluted days can deteriorate visibility due to their high extinction efficiency.

[Characteristics of Component Particle Size Distributions of Particulate Matter Emitted from a Waste Incineration Plant]

There are few analyses on the components of particulate matter emitted from waste incineration plants. In past studies, analyses of particle size distribution characteristics of the components were mainly targeted at particles with larger particle sizes. An electrical low pressure impactor (ELPI) was used in this study to collect the particulate matter emitted from a waste incineration plant, and the elements and carbonaceous components of these samples were analyzed. The particle size characteristics of organic carbon (OC), elemental carbon (EC), and heavy metal elements in 14 particle size segments were analyzed and composition profiles of elements and carbonaceous components of PM₁, PM_2.5, and PM₁₀ from the waste incineration plant were established to provide a reference for refined source apportionment research. The results showed that the main components of the waste incineration plant included Al, Si, S, Ca, Cr, Fe, OC, EC, etc. OC and Ca were dominating components, and mass fractions of these components in the PM_2.5 profile were 10.15% and 12.37%, respectively. The contents of heavy metals were ranked as Cr > Pb > Zn > Mn > Cu > Cd > Ni, and the mass fractions of Cr and Pb in PM_2.5 amounted to 1.83% and 0.74%, respectively. OC in the range of 2.39-3.99 and 6.68-9.91 μm accounted for 15.02% and 20.45% of the total OC content, respectively, and the content of OC in fine particles was higher than that in coarse particles. The content of EC in fine particles was much higher than that in coarse particles, and it accounted for 14.8% in the 0.382-0.613 μm particle size. Heavy metal elements such as Cr, Mn, Ni, Cu, Zn, Cd, and Pb were mainly concentrated in the fine particles.

[Pollution Characteristics and Source Apportionment of Ambient PM2.5 During Four Seasons in Yantai City]

PM_2.5 samples were collected at three sites in Yantai City during all four seasons of 2016-2017, and the mass concentration and chemical composition characteristics were analyzed. The CMB model was used to calculate source apportionment of ambient PM_2.5, and the backward trajectory cluster and PSCF were used to analyze the transport flow and potential source regions. The results showed that the average mass concentrations of PM_2.5 in winter, spring, summer, and autumn in Yantai were (89.45±56.80), (76.78±28.44), (32.65±17.92) and (57.32±24.60) μg·m^-3, respectively. The PM_2.5 concentration showed a significant seasonal variation (P<0.01). The contribution of PM_2.5 sources was as follows:secondary nitrate (20.3%) > crustal dust (15.7%) > vehicle exhaust (14.9%) > coal combustion (13.8%) > secondary sulphate (12.8%) > SOC (6.1%) > cement dust (5.5%) > sea salt source (2.9%). It can be seen that the predominant sources were secondary sources, crustal dust, vehicle exhaust, and coal combustion. The sources of nitrate in spring and of crustal dust were important contributors. The contribution of sulfate in summer was prominent, and the proportion of coal combustion was high in autumn and winter. Yantai City's airflow transport and potential source regions also showed significant seasonal changes:winters were mainly affected by short-distance transport in Yantai City; summers were mainly affected by the coastal of eastern Yantai City and local areas; springs and autumns were mainly affected by regional transmission in the northeast and in the eastern coastal areas of Shandong Province and by local sources in Yantai City.

[Source Apportionment and Heath Risk Quantification of Heavy Metals in PM2.5 in Yangzhou, China]

Recently, a new method combining positive matrix factorization (PMF) and heavy metal health risk (HMHR) assessment was proposed to apportion sources of heavy metals in ambient particulate matter and the associated heavy metal cancer health risk (HMCR), which has been applied to data collected in Yangzhou, China. The annual average concentrations of six measured heavy metals were Pb (64.4 ng·m^-3), followed by Cr (25.24 ng·m^-3), As (6.36 ng·m^-3), Ni (5.36 ng·m^-3), Cd (3.34 ng·m^-3), and Co (1.21 ng·m^-3). The results showed that the major sources of PM_2.5 were secondary sources (37.7%), followed by coal combustion (19.4%), resuspended dust (17.5%), vehicle emissions (16.9%), construction dust (5.2%), and industrial emissions (3.4%). As was primarily emitted from coal combustion, vehicle emissions, and resuspended dust. Co originated from industry emissions. Pb was mainly emitted from coal combustion. Ni and Cd were from industrial emissions. The major sources that contributed to HMCR were resuspended dust, coal combustion, vehicle emissions, industry emissions, and construction dust. The high contributions of resuspended dust and coal to HMCR were likely due to the high heavy metals concentrations in coal and the resuspended dust profile as well as high emissions of these sources.

[Chemical Source Profiles of PM Emitted from the Main Processes of the Iron and Steel Industry in China]

Considering the lack of numbers and updates of particulate matter (PM) source profiles, which show PM emitted from the Chinese iron and steel industry, a dilution tunnel system was used to sample PM discharged from the three main processes (sintering, puddling, and steelmaking) of an iron and steel company in Wuhan, China. Six source profiles for fine and coarse PM were established, and their characteristics were researched. The main conclusions were as follows:① For the sintering source profiles, SO₄^2-, Al, and NH₄⁺ were the dominant components, with mass fractions of 22.2%, 4.5%, and 3.5% in the PM_2.5 profile and 36.0%, 5.2%, and 2.7% in the PM₁₀ profile, respectively. Fe was abundant in puddling source profiles, the mass fractions of which reached 28.3% and 24.5% for PM_2.5 profile and PM₁₀ profile, respectively. As for steelmaking, the main components were Ca and Fe. ② For the element component features, S was enriched in the sintering source profiles. Metal elements, such as Pb and Cr, were more abundant in the puddling source profiles. ③ The coefficients of divergence for profiles were calculated. Profiles of different sizes for the same processes showed similarities, whereas the diversities between the sintering and the other two profiles were higher. 4 Compared with research in other regions, similarities and differences were found and analyzed.

[Clavien-Dindo classification and influencing factors analysis of complications after laparoscopic pancreaticoduodenectomy]

Objective: To semi-quantify the postoperative complications occurred after laparoscopic pancreaticoduodenectomy(LPD) using Clavien-Dindo score, thereafter exploring its impact factors. Methods: In this retrospective cohort study, the clinical data of 124 patients who had undergone LPD for periampullary tumor from June 2016 to June 2017 at Department of Biliary Pancreatic Surgery, Affiliated Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology were collected.Malignancy was confirmed based on postoperative pathological reports.Postoperative complications were semi-quantitated using Clavien-Dindo score.Multivariable logistic regression model was applied to explore the factors related to severe complications(Clavien-Dindo Ⅲb-Ⅴ). Results: Of the 124 patients, there were 64 males(51.6%) and 60 females(48.4%), with age of 57 years(range, 23-82 years). In total, postoperative complications occurred in 30 patients(24.2%). Among the 30 patients, 4 patients suffered Clavien-Dindo grade Ⅰ, 18 patients(14.5%) suffered Clavien-Dindo grade Ⅱ, 6 patients(4.8%) suffered Clavien-Dindo grade Ⅲa, 1 patient(0.1%) suffered Clavien-Dindo grade Ⅳb, and 1 patient(0.1%) suffered Clavien-Dindo grade Ⅴ.Intraabdominal hemorrhage occurred in 8 patients, pancreatic fistula was found in 10 patients(7 patients had biochemical leakage and 3 of them had grade B pancreatic fistula), both biliary fistula and gastrointestinal fistula were found in 1 patient.Abdominal infection occurred in 10 patients, both liver failure and renal failure occurred in one patient.Moreover, arrhythmia was found in two patients, and mortality occurred in one patient.Five patients suffered multiple complications.Univariable analysis showed that postoperative complications were associated with body mass index, American Society of Anesthesiologists(ASA) score, intraoperative blood transfusion, and pancreatic texture(P<0.05). In multivariable logistic regression, ASA grade Ⅲ, intraoperative blood transfusion, and pancreatic softness were independently related to postoperative complications after LPD(P<0.05). Conclusions: Clavien-Dindo score is feasible to be applied in management of patients with LPD.ASA score, texture of pancreas, and intraoperative blood transfusion were independently associated with postoperative complications.

[Effects of low level laser irradiation on the osteogenic capacity of sodium alginate/gelatin/human adipose-derived stem cells 3D bio-printing construct]

OBJECTIVE

To explore the effects of low level laser irradiation (LLLI) on the osteogenic capacity of three-dimensional (3D) structure by 3D bio-printing construct used human adipose-derived stem cells (hASCs) as seed cells.

METHODS

Using hASCs as seed cells, we prepared sodium alginate/gelatin/hASCs 3D bio-printing construct, and divided them into four groups: PM (proliferative medium), PM+LLLI, OM (osteogenic medium) and OM+LLLI, and the total doses of LLLI was 4 J/cm². Immunofluorescence microscopy was used to observe the viability of the cells, and analyze the expression of the osteogenesis-related protein Runt-related transcription factor 2 (Runx2) and osteocalcin (OCN).

RESULTS

The 3D constructs obtained by printing were examined by microscope. The sizes of these 3D constructs were 10 mm×10 mm×1.5 mm. The wall thickness of the printed gelatin mold was approximately 1 mm, and the pores were round and had a diameter of about 700 μm. The cell viability of sodium alginate/gelatin/hASCs 3D bio-printing construct was high, and the difference among the four groups was not significant. On day 7, the expression of OCN from high to low was group OM+LLLI, PM+LLLI, OM and PM. There were significant differences among these groups (P<0.01), but there was no significant difference between group PM+LLLI and OM. On day 14, the expression of OCN in each group was higher than that on day 7, and there was no significant difference between group OM+LLLI and OM. The expression of Runx2 in group OM+LLLI was more than 90%, significantly higher than that in group OM (P<0.01). But the expression of Runx2 in group PM+LLLI and OM+LLLI were significantly lower than that in the non-irradiated groups. The expression of osteogenesis-related protein Runx2 and OCN were higher in OM groups than in PM groups. Furthermore, the irradiated groups were significantly higher than the non-irradiated groups.

CONCLUSION

LLLI does not affect the cell viability of sodium alginate/gelatin/hASCs 3D bio-printing construct, and may promote the osteogenic differentiation of hASCs.

[Analysis of Chemical Composition of the Fine Particulate Matter in Summer in Tianjin City via a Single Particle Aerosol Mass Spectrometer (SPAMS)]

As an important megacity of the Beijing-Tianjin-Hebei air pollution transmission channel and the Bohai Sea Economic Zone, Tianjin is influenced by air pollution in recent years, thus research on the fine particulate matter in Tianjin is of vital value. In this study, single particle aerosol mass spectrometry (SPAMS) was used to measure data of Jinnan District in Tianjin during August 2017, to describe the chemical features of fine particles in summer ambient air and estimate the potential pollution sources of fine particles. By using the ART-2a clustering method, 12 classes of PM were acquired, such as elemental carbon particles, Fe-NO₃ particles, Na-K particles, and metal particles. After monitoring the size distribution and diurnal variation of fine particles, it was concluded that the ratio of EC particles decreased as the size increased, whereas dust particles and Fe-NO₃ particles showed the opposite trend; three types of EC particles varied differently in a day according to the photochemical reaction; and the ratio of Fe-NO₃ particles was elevated in the daytime because of industrial production during that period. Backward trajectories of daily airflow at the measured spot were also calculated. When the monitoring site was affected by the air mass from the southwest, coal-burning particles may have contributed more; whereas, when the air mass from the southeast occurred more frequently, biomass burning and sea salt particles possibly contributed more.

A new method to quantify the health risks from sources of perfluoroalkyl substances, combined with positive matrix factorization and risk assessment models

A hybrid model based on the positive matrix factorization (PMF) model and the health risk assessment model for assessing risks associated with sources of perfluoroalkyl substances (PFASs) in water was established and applied at Dianchi Lake to test its applicability. The new method contains 2 stages: 1) the sources of PFASs were apportioned by the PMF model and 2) the contribution of health risks from each source was calculated by the new hybrid model. Two factors were extracted by PMF, with factor 1 identified as aqueous fire-fighting foams source and factor 2 as fluoropolymer manufacturing and processing and perfluorooctanoic acid production source. The health risk of PFASs in the water assessed by the health risk assessment model was 9.54 × 10^-7  a^-1 on average, showing no obvious adverse effects to human health. The 2 sources' risks estimated by the new hybrid model ranged from 2.95 × 10^-10 to 6.60 × 10^-6  a^-1 and from 1.64 × 10^-7 to 1.62 × 10^-6  a^-1 , respectively. The new hybrid model can provide useful information on the health risks of PFAS sources, which is helpful for pollution control and environmental management. Environ Toxicol Chem 2018;37:107-115. © 2017 SETAC.

[Seasonal Variation of Carbon Fractions in PM2.5 in Heze]

PM_2.5 samples were collected in Heze from August 2015 to April 2016. Eight carbon fractions were analyzed by a thermal/optical carbon analyzer, and organic carbon (OC) and elemental carbon (EC) analyses were obtained. The OC/EC ratio and the correlation between OC and EC were analyzed. Secondary organic carbon (SOC) mass concentration was estimated by the OC/EC ratio method; and eight carbon fractions were analyzed using a principal component analysis. The results showed that:① The annual average mass concentrations of OC and EC were 1.2-60.6 μg·m^-3 and 0.6-24.8 μg·m^-3, respectively; and the characterization of OC and EC percentages in PM_2.5 during different seasons were similar with winter > spring > autumn > summer. ② The annual average OC/EC ratio was 2.6±1.0, and the correlations between OC and EC during spring, summer, autumn, and winter were 0.91, 0.56, 0.86, and 0.75, respectively, and the estimated mass concentration of SOC was (4.7±5.0) μg·m^-3. ③ The characterization of eight carbon fractions percentages in PM_2.5 in the different seasons demonstrated similar seasonal variations, with EC1 having the highest percentage and EC3 having the lowest percentage. The result of the principal component analysis showed that coal burning, motor vehicle emissions, and biomass burning were the major sources of carbon.

Source profiles and contributions of biofuel combustion for PM2.5, PM10 and their compositions, in a city influenced by biofuel stoves

Source and ambient samples were collected in a city in China that uses considerable biofuel, to assess influence of biofuel combustion and other sources on particulate matter (PM). Profiles and size distribution of biofuel combustion were investigated. Higher levels in source profiles, a significant increase in heavy-biomass ambient and stronger correlations of K⁺, Cl^-, OC and EC suggest that they can be tracers of biofuel combustion. And char-EC/soot-EC (8.5 for PM_2.5 and 15.8 for PM₁₀ of source samples) can also be used to distinguish it. In source samples, water-soluble organic carbon (WSOC) were approximately 28.0%-68.8% (PM_2.5) and 27.2%-43.8% (PM₁₀) of OC. For size distribution, biofuel combustion mainly produces smaller particles. OC1, OC2, EC1 and EC2 abundances showed two peaks with one below 1 μm and one above 2 μm. An advanced three-way factory analysis model was applied to quantify source contributions to ambient PM_2.5 and PM₁₀. Higher contributions of coal combustion, vehicular emission, nitrate and biofuel combustion occurred during the heavy-biomass period, and higher contributions of sulfate and crustal dust were observed during the light-biomass period. Mass and percentage contributions of biofuel combustion were significantly higher in heavy-biomass period. The biofuel combustion attributed above 45% of K⁺ and Cl^-, above 30% of EC and about 20% of OC. In addition, through analysis of source profiles and contributions, they were consistently evident that biofuel combustion and crustal dust contributed more to cation than to anion, while sulfate & SOC and nitrate showed stronger influence on anion than on cation.

[Characteristics Research on Carbonaceous Component of Particulate Matter Emitted from Iron and Steel Industry]

In order to investigate the carbonaceous characteristics of particles emitted from the iron and steel industry, an electrical low-pressure impactor (ELPI) was used to collect three sets of samples from the sintering process and one set of samples from the ironmaking process emissions of particulate matters. Organic carbon (OC) and elemental carbon (EC), which were divided into seven carbonaceous components based on the temperature of the particulate matter, were analyzed using a thermal-light reflection method. Results show that OC in sintering process particles is higher than that in ironmaking particles and accounts for 5.3%±2.3% and 7.1%±3.0% of PM₁₀ and PM_2.5, respectively, which reveals that OC tended to be enriched in fine particles. In the ironmaking process particles, OC accounted for 2.5% and 2.0% of PM₁₀ and PM_2.5, respectively. The relative proportions of the seven carbonaceous components in the four sets of samples were very similar. OC2 and OC3 accounted for the highest proportion; the EC1, EC2, and EC3 contents decreased in turn; and OC1 may be associated with boiler scale and desulfurization. In addition, the OC and EC of sintering process particles had higher correlation, and the OC/EC value of primary emission particles was 4.7±0.7, which is much higher than the value of the secondary OC estimation index in environment. Analyzing deeply on the carbonaceous characteristics in particles emitted from the iron and steel industry, which will provide essential data for source apportionment of carbonaceous aerosols in environment and will be conducive to the follow supervisory of pollution cleaning in iron and steel industry.

Size distribution, directional source contributions and pollution status of PM from Chengdu, China during a long-term sampling campaign

Long-term and synchronous monitoring of PM₁₀ and PM_2.5 was conducted in Chengdu in China from 2007 to 2013. The levels, variations, compositions and size distributions were investigated. The sources were quantified by two-way and three-way receptor models (PMF2, ME2-2way and ME2-3way). Consistent results were found: the primary source categories contributed 63.4% (PMF2), 64.8% (ME2-2way) and 66.8% (ME2-3way) to PM₁₀, and contributed 60.9% (PMF2), 65.5% (ME2-2way) and 61.0% (ME2-3way) to PM_2.5. Secondary sources contributed 31.8% (PMF2), 32.9% (ME2-2way) and 31.7% (ME2-3way) to PM₁₀, and 35.0% (PMF2), 33.8% (ME2-2way) and 36.0% (ME2-3way) to PM_2.5. The size distribution of source categories was estimated better by the ME2-3way method. The three-way model can simultaneously consider chemical species, temporal variability and PM sizes, while a two-way model independently computes datasets of different sizes. A method called source directional apportionment (SDA) was employed to quantify the contributions from various directions for each source category. Crustal dust from east-north-east (ENE) contributed the highest to both PM₁₀ (12.7%) and PM_2.5 (9.7%) in Chengdu, followed by the crustal dust from south-east (SE) for PM₁₀ (9.8%) and secondary nitrate & secondary organic carbon from ENE for PM_2.5 (9.6%). Source contributions from different directions are associated with meteorological conditions, source locations and emission patterns during the sampling period. These findings and methods provide useful tools to better understand PM pollution status and to develop effective pollution control strategies.

[Changes of integrin-linked kinase expression on rats' pulmonary fibrosis induced by paraquat]

Objective: To observe the expression of integrin-linked kinase on pulmonary fibrosis of paraquat (PQ) poisoning rats, and to discuss the relationship between ILK with pulmonary fibrosis induced by paraquat. Methods: Forty male Sprague-Dawley (SD) rats were randomly divided into control group and paraquat group, 20 in each group; the PQ group rats were intraperitoneally injected PQ liquid (18 mg/kg) , and the control group rats were injected the same volume of saline; 5 rats of these two groups were respectively sacrificed after 7, 14, 28, 56 days of PQ injection; according to the results of lung biopsy HE staining and Masson staining to observe the lung pathologic changes, measure the value of lung hydroxyproline and the expression of ILK. Results: HE and Masson staining of lung pathological biopsy showed, the 7th day after PQ exposure lung tissue mostly had congestion, edema, inflammatory cells infiltration; the 14th inflammation reduced, fibrosis change appeared gradually; the 28th and 56th showed the lung tissue structure disorder and occurred apparent hydroproline with blue dye in pulmonary interstitium. Compared with control group in the same experiment period, the value of lung hydroxyproline in each experiment period of PQ group increased (P<0.05) , and the value of lung hydroxyproline of PQ group rose with the increasing of the time of PQ poisoning. The expression of ILK mRNA and protein in each experiment period of PQ group was higher than the control group in the same experiment period (P<0.05) ; ILK mRNA and protein of PQ group began to increase on 7 day phase, reached the highest on 28 day phase, and decreased on 56 day phase. Conclusion: The expression of ILK mRNA and protein increased with the lung fibrosis progression of PQ poisoning rats, so ILK could be the key molecule target which induced pulmonary fibrosis of PQ poisoning.

Source apportionment and heavy metal health risk (HMHR) quantification from sources in a southern city in China, using an ME2-HMHR model

Heavy metals (Cr, Co, Ni, As, Cd, and Pb) can be bound to PM adversely affecting human health. Quantifying the source impacts on heavy metals can provide source-specific estimates of the heavy metal health risk (HMHR) to guide effective development of strategies to reduce such risks from exposure to heavy metals in PM_2.5 (particulate matter (PM) with aerodynamic diameter less than or equal to 2.5 μm). In this study, a method combining Multilinear Engine 2 (ME2) and a risk assessment model is developed to more effectively quantify source contributions to HMHR, including heavy metal non-cancer risk (non-HMCR) and cancer risk (HMCR). The combined model (called ME2-HMHR) has two steps: step1, source contributions to heavy metals are estimated by employing the ME2 model; step2, the source contributions in step 1 are introduced into the risk assessment model to calculate the source contributions to HMHR. The approach was applied to Huzou, China and five significant sources were identified. Soil dust is the largest source of non-HMCR. For HMCR, the source contributions of soil dust, coal combustion, cement dust, vehicle, and secondary sources are 1.0 × 10^-4, 3.7 × 10^-5, 2.7 × 10^-6, 1.6 × 10^-6 and 1.9 × 10^-9, respectively. The soil dust is the largest contributor to HMCR, being driven by the high impact of soil dust on PM_2.5 and the abundance of heavy metals in soil dust.

[Analgesic effects of ionotropic glutamate receptor antagonists MK-801 and NBQX on collagen-induced arthritis rats]

OBJECTIVE

The ionotropic glutamate receptorantagonists include two types: MK-801, antagonist of N-methyl-D-asparticacid (NMDA) receptor, and NBQX, antagonist of non-NMDA receptor.The above-mentioned ionotropic antagonists can block the glutamate and its corresponding receptor binding to produce analgesic effect. The objective of this research was to study two antagonists in analgesic effect on rat behavior,as well as to investigate the down-regulation and up-regulation of cyclooxygenase-2 (COX-2) and Janus-activated kinase (Jak3) in collagen-induced arthritis (CIA) rat serum and tissue fluid after the application of these antagonists, that is, the effect on molecular biology.

METHODS

This study used the ionotropic glutamate receptors as the target and established CIA rat model. Vivo studies were used to observe changes in behavior and molecular biology of the CIA rat.Behavioral assessment includedmechanical allodynia and joint swelling in the CIA rat,where themechanical allodynia was measured using the paw-withdrawal threshold (PWT) with VonFrey filaments according to the "Up-Down" method,and the drainage volume was used to assess joint swelling. Then the blood samples taken from the heart of the rat and the tissue homogenate were collected to detect the down-regulation and up-regulation of COX-2 and Jak3 in the serum and tissue fluid after the antagonists wereused.

RESULTS

Using MK-801, NBQX alone or using the combination of these two antagonists,these three methods all could alleviate pain(P<0.01).The analgesic effect lasted more than 24 h.Both antagonists reached the peak of analgesia at the end of 4 hours post-injection. NBQX had stronger analgesic effect than MK-801 (P<0.05).Whether alone or combined use of these two antagonists,could not change the CIA rats' swelling of the joint (P>0.05). MK-801 could decrease the expression of COX-2 (P<0.01).At the same time, NBQX did not have this effect (P>0.05). Using MK-801, NBQX alone or combination of these two antagonists could not affect the increased expression of Jak3 caused by the CIA (P>0.05).

CONCLUSION

MK-801 and NBQX could both alleviate pain, NBQX was much better than MK-801. Neither MK-801 nor NBQX had the effect on the swelling of the joint. NMDA receptor and COX-2 inflammatory pathways had certain interactions. For Jak3, it could not be found to have cross-function with ionotropic glutamate signaling pathways by this experiment.

Characterization and source apportionment of size-segregated atmospheric particulate matter collected at ground level and from the urban canopy in Tianjin

To investigate the size distributions of chemical compositions and sources of particulate matter (PM) at ground level and from the urban canopy, a study was conducted on a 255 m meteorological tower in Tianjin from December 2013 to January 2014. Thirteen sets of 8 size-segregated particles were collected with cascade impactor at 10 m and 220 m. Twelve components of particles, including water-soluble inorganic ions and carbonaceous species, were analyzed and used to apportion the sources of PM with positive matrix factorization. Our results indicated that the concentrations, size distributions of chemical compositions and sources of PM at the urban canopy were affected by regional transport due to a stable layer approximately 200 m and higher wind speed at 220 m. The concentrations of PM, Cl^- and elemental carbon (EC) in fine particles at 10 m were higher than that at 220 m, while the reverse was true for NO₃^- and SO₄^2-. The concentrations of Na⁺, Ca²⁺, Mg²⁺, Cl^- and EC in coarse particles at 10 m were higher than that at 220 m. The size distributions of major primary species, such as Cl^-, Na⁺, Ca²⁺, Mg²⁺ and EC, were similar at two different heights, indicating that there were common and dominant sources. The peaks of SO₄^2-, NH₄⁺, NO₃^- and organic carbon (OC), which were partly secondary generated species, shifted slightly to the smaller particles at 220 m, indicating that there was a different formation mechanism. Industrial pollution and coal combustion, re-suspended dust and marine salt, traffic emissions and transport, and secondary inorganic aerosols were the major sources of PM at both heights. With the increase in vertical height, the influence of traffic emissions, re-suspended dust and biomass burning on PM weakened, but the characteristics of regional transport from Hebei Province and Beijing gradually become obvious.

Seasonal and regional variations of source contributions for PM10 and PM2.5 in urban environment

To characterize the sources of to PM10 and PM2.5, a long-term, speciate and simultaneous dataset was sampled in a megacity in China during the period of 2006-2014. The PM concentrations and PM2.5/PM10 were higher in the winter. Higher percentages of Al, Si, Ca and Fe were observed in the summer, and higher concentrations of OC, NO3(-) and SO4(2-) occurred in the winter. Then, the sources were quantified by an advanced three-way model (defined as an ABB three-way model), which estimates different profiles for different sizes. A higher percentage of cement and crustal dust was present in the summer; higher fractions of coal combustion and nitrate+SOC were observed in the winter. Crustal and cement contributed larger portion to coarse part of PM10, whereas vehicular and secondary source categories were enriched in PM2.5. Finally, potential source contribution function (PSCF) and source regional apportionment (SRA) methods were combined with the three-way model to estimate geographical origins. During the sampling period, the southeast region (R4) was an important region for most source categories (0.6%-11.5%); the R1 (centre region) also played a vital role (0.3-6.9%).

Sediment PAH source apportionment in the Liaohe River using the ME2 approach: A comparison to the PMF model

Environmental contaminant source apportionment is essential for pollution management and control. This study analysed surface sediment samples for 16 priority polycyclic aromatic hydrocarbons (PAHs). PAH sources were identified by two receptor models, which included positive matrix factorization (PMF) and multilinear engine 2 (ME2). Three PAH sources in the Liaohe River sediments were identified by PMF, including traffic, coke oven and coal combustion. The ME2 model apportioned one additional source. The two models yielded excellent correlation coefficients between the measured and predicted PAH concentrations. Traffic emission was the primary PAH source associated with the Liaohe River sediments, with estimated PMF contributions of 58% in May and 63% in September. Coke oven (19%-25%) and coal combustion (13%-18%) were the other two major PAH sources. For ME2, gasoline and diesel were separated: accounted for 14% in May and 16% in September; and 53% in May and 48% in September. This study marks the first application of the ME2 model to study sediment contaminant source apportionment. The methodology can potentially be applied to other aquatic environment contaminants.

Influence of quarry mining dust on PM2.5 in a city adjacent to a limestone quarry: Seasonal characteristics and source contributions

To understand the influence of quarry mining dust on particulate matter, ambient PM2.5 and quarry mining dust source samples were collected in a city near quarry facilities during 2013-2014. Samples were subject to chemical analysis for dust-related species (Al, Si, Ca, Fe, Ti), tracer metals, carbon components and water-soluble ions. Seasonal variations of PM2.5 and its main chemical components were investigated. Distinctive seasonal variations of PM2.5 were observed, with the highest PM2.5 concentrations (112.42μgm(-3)) in fall and lowest concentrations in summer (45.64μgm(-3)). For dust-related species, mass fractions of Si and Al did not show obvious seasonal variations, whereas Ca presented higher fractions in spring and summer and lower fractions in fall and winter. A combined receptor model (PMF-CMB) was applied to quantify the quarry mining dust contribution to PM2.5. Seven sources were identified, including quarry mining dust, soil dust, cement dust, coal combustion vehicles, secondary sulfate and secondary nitrate. On a yearly average basis, the contribution of quarry mining dust to PM2.5 was 6%. The contribution of soil dust to PM2.5 was comparable with cement dust (13% and 13%, respectively). Other identified sources included vehicle, secondary sulfate, secondary nitrate and coal combustion, which contributed 23, 15, 9 and 18% of the total mass, respectively. Air mass residence time (AMRT) analysis showed that northeast and southeast regions might be the major PM2.5 source during the sampling campaign. The findings of this study can be used to understand the characteristics of quarry mining dust and control strategies for PM2.5.

Source regional contributions to PM2.5 in a megacity in China using an advanced source regional apportionment method

To quantify contributions of individual source categories from diverse regions to PM2.5, PM2.5 samples were collected in a megacity in China and analyzed through a newly developed source regional apportionment (SRA) method. Levels, compositions and seasonal variations of speciated PM2.5 dataset were investigated. Sources were determined by Multilinear Engine 2 (ME2) model, and results showed that the PM2.5 in Tianjin was mainly influenced by secondary sulphate & secondary organic carbon SOC (percent contribution of 26.2%), coal combustion (24.6%), crustal dust & cement dust (20.3%), secondary nitrate (14.9%) and traffic emissions (14.0%). The SRA method showed that northwest region R2 was the highest regional contributor to secondary sources, with percent contributions to PM2.5 being 9.7% for secondary sulphate & SOC and 6.0% for secondary nitrates; the highest coal combustion was from local region R1 (6.2%) and northwest R2 (8.0%); the maximum contributing region to crustal & cement dust was southeast region R4 (5.0%); and contributions of traffic emissions were relatively spatial homogeneous. The seasonal variation of regional source contributions was observed: in spring, the crustal and cement dust contributed a higher percentage and the R4 was an important contributor; the secondary process attributed an increase fraction in summer; the mixed coal combustion from southwest R5 enhanced in autumn.

Advancement of highly charged ion beam production by superconducting ECR ion source SECRAL (invited)

At Institute of Modern Physics (IMP), Chinese Academy of Sciences (CAS), the superconducting Electron Cyclotron Resonance (ECR) ion source SECRAL (Superconducting ECR ion source with Advanced design in Lanzhou) has been put into operation for about 10 years now. It has been the main working horse to deliver intense highly charged heavy ion beams for the accelerators. Since its first plasma at 18 GHz, R&D work towards more intense highly charged ion beam production as well as the beam quality investigation has never been stopped. When SECRAL was upgraded to its typical operation frequency 24 GHz, it had already showed its promising capacity of very intense highly charged ion beam production. And it has also provided the strong experimental support for the so called scaling laws of microwave frequency effect. However, compared to the microwave power heating efficiency at 18 GHz, 24 GHz microwave heating does not show the ω(2) scale at the same power level, which indicates that microwave power coupling at gyrotron frequency needs better understanding. In this paper, after a review of the operation status of SECRAL with regard to the beam availability and stability, the recent study of the extracted ion beam transverse coupling issues will be discussed, and the test results of the both TE01 and HE11 modes will be presented. A general comparison of the performance working with the two injection modes will be given, and a preliminary analysis will be introduced. The latest results of the production of very intense highly charged ion beams, such as 1.42 emA Ar(12+), 0.92 emA Xe(27+), and so on, will be presented.

High intensity high charge state ion beam production with an evaporative cooling magnet ECRIS

LECR4 (Lanzhou ECR ion source No. 4) is a room temperature electron cyclotron resonance ion source, designed to produce high current, high charge state ion beams for the SSC-LINAC injector (a new injector for sector separated cyclotron) at the Institute of Modern Physics. LECR4 also serves as a PoP machine for the application of evaporative cooling technology in accelerator field. To achieve those goals, LECR4 ECR ion source has been optimized for the operation at 18 GHz. During 2014, LECR4 ion source was commissioned at 18 GHz microwave of 1.6 kW. To further study the influence of injection stage to the production of medium and high charge state ion beams, in March 2015, the injection stage with pumping system was installed, and some optimum results were produced, such as 560 eμA of O(7+), 620 eμA of Ar(11+), 430 eμA of Ar(12+), 430 eμA of Xe(20+), and so on. The comparison will be discussed in the paper.

24 GHz microwave mode converter optimized for superconducting ECR ion source SECRAL

Over-sized round waveguide with a diameter about Ø33.0 mm excited in the TE01 mode has been widely adopted for microwave transmission and coupling to the ECR (Electron Cyclotron Resonance) plasma with the superconducting ECR ion sources operating at 24 or 28 GHz, such as SECRAL and VENUS. In order to study the impact of different microwave modes on ECRH (Electron Cyclotron Resonance Heating) efficiency and especially the production of highly charged ions, a set of compact and efficient TE01-HE11 mode conversion and coupling system applicable to 24 GHz SECRAL whose overall length is 330 mm has been designed, fabricated and tested. Good agreements between off-line tests and calculation results have been achieved, which indicates the TE01-HE11 converter meets the application design. The detailed results of the optimized coupling system will be presented in the paper.

Insights into the chemical characterization and sources of PM(2.5) in Beijing at a 1-h time resolution

As the widespread application of online instruments penetrates the environmental fields, it is interesting to investigate the sources of fine particulate matter (PM2.5) based on the data monitored by online instruments. In this study, online analyzers with 1-h time resolution were employed to observe PM2.5 composition data, including carbon components, inorganic ions, heavy metals and gas pollutants, during a summer in Beijing. Chemical characteristics, temporal patterns and sources of PM2.5 are discussed. On the basis of hourly data, the mean concentration value of PM2.5 was 62.16±39.37 μg m(-3) (ranging from 6.69 to 183.67 μg m(-3)). The average concentrations of NO3(-), SO4(2-), NH4(+), OC and EC, the major chemical species, were 15.18±13.12, 14.80±14.53, 8.90±9.51, 9.32±4.16 and 3.08±1.43 μg m(-3), respectively. The concentration of PM2.5 varied during the online-sampling period, initially increasing and then subsequently decreasing. Three factor analysis models, including principal component analysis (PCA), positive matrix factorization (PMF) and Multilinear Engine 2 (ME2), were applied to apportion the PM2.5 sources. Source apportionment results obtained by the three different models were in agreement. Four sources were identified in Beijing during the sampling campaign, including secondary sources (38-39%), crustal dust (17-22%), vehicle exhaust (25-28%) and coal combustion (15-16%). Similar source profiles and contributions of PM2.5 were derived from ME2 and PMF, indicating the results of the two models are reasonable. The finding provides information that could be exploited for regular air control strategies.

The development of a room temperature electron cyclotron resonance ion source (Lanzhou electron cyclotron resonance ion source No. 4) with evaporative cooling technology at Institute of Modern Physics

LECR4 (Lanzhou electron cyclotron resonance ion source No. 4) has been successfully constructed at IMP and has also been connected with the Low Energy Beam Transport (LEBT) and Radio Frequency Quadrupole (RFQ) systems. These source magnet coils are cooled through evaporative cooling technology, which is the first attempt with an ECR ion source in the world. The maximum mirror field is 2.5 T (with iron plug) and the effective plasma chamber volume is 1.2 l. It was designed to be operated at 18 GHz and aimed to produce intense multiple charge state heavy ion beams for the linear injector project SSC-Linac at IMP. In February 2014, the first analyzed beam at 18 GHz was extracted. During about three months' commissioning, some outstanding results have been achieved, such as 1.97 emA of O(6+), 1.7 emA of Ar(8+), 1.07 emA of Ar(9+), and 118 euA of Bi(28+). The source has also successfully delivered O(5+) and Ar(8+) ion beams for RFQ commissioning in April 2014. This paper will give a brief overview of the design of LECR4. Then, the latest results of this source at 18 GHz will be presented.

Further insights into the composition, source, and toxicity of PAHs in size-resolved particulate matter in a megacity in China

Concentrations of particulate matter with an aerodynamic diameter less than 10 μm (PM10 ) and PM with an aerodynamic diameter less than 2.5 μm (PM2.5 ), and 16 polycyclic aromatic hydrocarbons (PAHs) were measured. The average concentrations of PM10 and PM2.5 reached 209.75 μg/m(3) and 141.87 μg/m(3) , respectively, and those of ΣPAHs were 41.46 ng/m(3) for PM10 and 36.77 ng/m(3) for PM2.5 . The mass ratio concentrations were 219.23 μg/g and 311.01 μg/g in PM10 and PM2.5 , respectively. Three sources and their contributions for PAHs were obtained. For individual input mode, diesel exhaust contributed 46.77% (PM10 ) and 41.12% (PM2.5 ) for mass concentration and 48.69% (PM10 ) and 39.47% (PM2.5 ) for mass ratio concentration; gasoline exhaust contributed 31.02% (PM10 ) and 39.47% (PM2.5 ) for mass concentration and 28.95% (PM10 ) and 36.46% (PM2.5 ) for mass ratio concentration; and coal combustion contributed 22.22% (PM10 ) and 19.41% (PM2.5 ) for mass concentration and 22.36% (PM10 ) and 15.89% (PM2.5 ) for mass ratio concentration. For combined input mode, the same source categories were obtained. Source contributions to PM10 and PM2.5 were diesel exhaust (40.70% and 36.64%, respectively, for mass concentration; 49.19% and 38.47%, respectively, for mass ratio concentration), gasoline exhaust (35.09% and 38.47%, respectively, for mass concentration; 32.50% and 33.43%, respectively, for mass ratio concentration), and coal combustion (24.21% and 24.89%, respectively, for mass concentration; 18.31% and18.17%, respectively, for mass ratio concentration). Source risk assessment showed that vehicle emission was a significant contributor. The findings can help elucidate sources of PAHs and provide evidence supporting further applications of the Unmix model and additional studies about PAHs. Environ Toxicol Chem 2015;34:480-487. © 2014 SETAC.

Source apportionment of synchronously size segregated fine and coarse particulate matter, using an improved three-way factor analysis model

Samples of PM₁₀ and PM₂.₅ were synchronously collected from a megacity in China (Chengdu) during the 2011 sampling campaign and then analyzed by an improved three-way factor analysis method based on ME2 (multilinear engine 2), to investigate the contributions and size distributions of the source categories for size segregated particulate matter (PM). Firstly, the synthetic test was performed to evaluate the accuracy of the improved three-way model. The same five source categories with slightly different source profiles were caught. The low AAE (average absolute error) values between the estimated and the synthetic source contributions (<15%) and the approachable estimated PM₂.₅/PM₁₀ ratios with the simulated ratios might indicate that the results of the improved three-way factor analysis might be satisfactory. Then, for the ambient PM samples, the mean levels were 206.65 ± 69.90 μg/m(3) (PM₁₀) and 130.47 ± 43.67 μg/m(3) (PM₂.₅). The average ratio of PM₂.₅/PM₁₀ was 0.63. PM₁₀ and PM₂.₅ in Chengdu were influenced by the same source categories and their percentage contributions were in the same order: crustal dust & coal combustion presented the highest percentage contributions, accounting for 58.20% (PM₁₀) and 53.73% (PM2.5); followed by vehicle exhaust & secondary organic carbon (18.45% for PM₁₀ and 21.63% for PM₂.₅), secondary sulfate and nitrate (17.06% for PM₁₀ and 20.91% for PM₂.₅) and cement dust (6.30% for PM₁₀ and 3.73% for PM₂.₅). The source profiles and contributions presented slightly different distributions for PM₁₀ and PM₂.₅, which could better reflect the actual situation. The findings based on the improved three-way factor analysis method may provide clear and deep insights into the sources of synchronously size-resolved PM.

Particulate matter mass and chemical component concentrations over four Chinese cities along the western Pacific coast

China has witnessed rapid economic growth in the past three decades, especially in coastal areas. Particulate matter (PM) pollution is becoming increasingly serious in China's cities along the western Pacific coast with the rapid development of China's society and economy. This study analyzed PM (PM10 and PM2.5) in terms of their mass and chemical composition in four coastal Chinese cities. The goal was to study the spatial variation and characteristics of PM pollution in sites under different levels of economic development and in diverse natural environments. A distinct trend for concentrations of PM and related chemical species was observed and increased from south to north in Haikou, Ningbo, Qingdao, and Tianjin. Secondary inorganic aerosols, crustal materials, and organic matter dominated the composition of both PM10 and PM2.5. Crustal materials were the most abundant species in the northern coastal areas because these areas have less vegetation cover and lower humidity than southern coastal areas. The presence of high SO4 (2-)/nitrate (NO3 (-)) concentrations indicated that the burning of coals gives significant contributions to PM10 and PM2.5. The differences observed in the characteristics of PM pollution in these coastal cities are probably caused by different levels of industrial and urban development.

Using an improved Source Directional Apportionment method to quantify the PM(2.5) source contributions from various directions in a megacity in China

The transport of particulate matter (PM) and chemical species is an essential mechanism for determining the fate of PM pollutants and their effects. To determine source transport quantitatively, an ambient PM2.5 dataset from a megacity in China was analysed using a novel method called "Source Directional Apportionment" (SDA). The SDA method is developed in this work to quantify contributions of each source category from various directions. The three steps of SDA are (1) to estimate source categories and time series of source contributions to PM with a factor analysis model, (2) to identify directions by trajectory cluster analysis and (3) to quantify source directional contributions for each source category by combining the time series of source contributions to the back trajectories in each direction. For PM2.5 in Chengdu, crustal dust, vehicular exhaust, coal combustion and secondary sulphate are all important contributors to PM; secondary nitrate and cement dust are relatively less influential. Four potential source directions were identified in Chengdu during the sampling period from 2009 to 2011. The percentages of source directional contributions from Directions 1-4 (northeast, southwest to south, southwest and west) were estimated as follows: crustal dust (7.9%, 9.1%, 6.4% and 6.2%, respectively), cement dust (1.0%, 1.2%, 1.3% and 1.1%, respectively), vehicular exhaust (6.4%, 6.0%, 5.6% and 7.0%, respectively), secondary sulphate (5.1%, 5.2%, 5.6% and 8.6%, respectively) and secondary nitrate (2.0%, 2.4%, 2.5% and 2.3%, respectively). Finally, the source directional contributions to important chemical species were quantified to determine their transport from sources to receptor.

Physically constrained source apportionment (PCSA) for polycyclic aromatic hydrocarbon using the Multilinear Engine 2-species ratios (ME2-SR) method

An improved physically constrained source apportionment (PCSA) technology using the Multilinear Engine 2-species ratios (ME2-SR) method was proposed and applied to quantify the sources of PM10- and PM2.5-associated polycyclic aromatic hydrocarbons (PAHs) from Chengdu in winter time. Sixteen priority PAH compounds were detected with mean ΣPAH concentrations (sum of 16 PAHs) ranging from 70.65 ng/m(3) to 209.58 ng/m(3) and from 59.17 ng/m(3) to 170.64 ng/m(3) for the PM10 and PM2.5 samples, respectively. The ME2-SR and positive matrix factorization (PMF) models were employed to estimate the source contributions of PAHs, and these estimates agreed with the experimental results. For the PMF model, the highest contributor to the ΣPAHs was vehicular emission (81.69% for PM10, 82.06% for PM2.5), followed by coal combustion (12.68%, 12.11%), wood combustion (5.65%, 4.45%) and oil combustion (0.72%, 0.88%). For the ME2-SR method, the highest contributions were from diesel (43.19% for PM10, 47.17% for PM2.5) and gasoline exhaust (34.94%, 32.44%), followed by wood combustion (8.79%, 6.37%), coal combustion (12.46%, 12.37%) and oil combustion (0.80%, 1.22%). However, the PAH ratios calculated for the factors extracted by ME2-SR were closer to the values from actual source profiles, implying that the results obtained from ME2-SR might be physically constrained and satisfactory.

Transverse coupling property of beam from ECR ion sources

Experimental evidence of the property of transverse coupling of beam from Electron Cyclotron Resonance (ECR) ion source is presented. It is especially of interest for an ECR ion source, where the cross section of extracted beam is not round along transport path due to the magnetic confinement configuration. When the ions are extracted and accelerated through the descending axial magnetic field at the extraction region, the horizontal and vertical phase space strongly coupled. In this study, the coupling configuration between the transverse phase spaces of the beam from ECR ion source is achieved by beam back-tracking simulation based on the measurements. The reasonability of this coupling configuration has been proven by a series of subsequent simulations.

A new receptor model-incremental lifetime cancer risk method to quantify the carcinogenic risks associated with sources of particle-bound polycyclic aromatic hydrocarbons from Chengdu in China

PM10 and PM2.5 samples were simultaneously collected during a one-year monitoring period in Chengdu. The concentrations of 16 particle-bound polycyclic aromatic hydrocarbons (Σ16PAHs) were measured. Σ16PAHs concentrations varied from 16.85 to 160.24 ng m(-3) and 14.93 to 111.04ngm(-3) for PM10 and PM2.5, respectively. Three receptor models (principal component analysis (PCA), positive matrix factorization (PMF), and Multilinear Engine 2 (ME2)) were applied to investigate the sources and contributions of PAHs. The results obtained from the three receptor models were compared. Diesel emissions, gasoline emissions, and coal and wood combustion were the primary sources. Source apportionment results indicated that these models were able to track the ΣPAHs. For the first time, the cancer risks for each identified source were quantitatively calculated for ingestion and dermal contact routes by combining the incremental lifetime cancer risk (ILCR) values with the estimated source contributions. The results showed that gasoline emissions posed the highest cancer risk, even though it contributed less to Σ16PAHs. The results and method from this work can provide useful information for quantifying the toxicity of source categories and studying human health in the future.

Studies on a Q/A selector for the SECRAL electron cyclotron resonance ion source

Electron cyclotron resonance ion sources are widely used in heavy ion accelerators in the world because they are capable of producing high current beams of highly charged ions. However, the design of the Q/A selector system for these devices is challenging, because it must have a sufficient ion resolution while controlling the beam emittance growth. Moreover, this system has to be matched for a wide range of ion beam species with different intensities. In this paper, research on the Q/A selector system at the SECRAL (Superconducting Electron Cyclotron Resonance ion source with Advanced design in Lanzhou) platform both in experiment and simulation is presented. Based on this study, a new Q/A selector system has been designed for SECRAL II. The features of the new design including beam simulations are also presented.