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Background Several observational studies reported on the association between particulate matter ≥2.5≥m (PM2.5) and its absorbance with coronavirus (COVID-19), but none use Mendelian randomisation (MR). To strengthen the knowledge on causality, we examined the association of PM2.5 and its absorbance with COVID-19 risk using MR. Methods We selected genome-wide association study (GWAS) integration data from the UK Biobank and IEU Open GWAS Project for two-sample MR analysis. We used inverse variance weighted (IVW) and its multiple random effects and fixed effects alternatives to generally predict the association of PM2.5 and its absorbance with COVID-19, and six methods (MR Egger, weighted median, simple mode, weighted mode, maximum-likelihood and MR-PRESSO) as complementary analyses. Results MR results suggested that PM2.5 absorbance was associated with COVID-19 infection (odds ratio (OR)=2.64; 95% confidence interval (CI)=1.32-5.27, P=0.006), hospitalisation (OR= 3.52; 95% CI = 1.05-11.75, P = 0.041) and severe respiratory symptoms (OR=28.74; 95% CI=4.00-206.32, P=0.001) in IVW methods. We observed no association between PM2.5 and COVID-19. Conclusions We found a potential causal association of PM2.5 absorbance with COVID-19 infection, hospitalisation, and severe respiratory symptoms using MR analysis. Prevention and control of air pollution could help delay and halt the negative progression of COVID-19. [ABSTRACT FROM AUTHOR]

Aim: To investigate the relationship of small dense low-density lipoprotein cholesterol (sdLDL-C) to carotid artery intima-media thickness (CA-IMT) and carotid plaque (CAP) in Chinese general population, and to evaluate whether sdLDL-C could be an independent risk factor for individuals with subclinical atherosclerosis.Methods: A total of 729 subjects were randomly collected from consecutive individuals from April 2019 to April 2020 for an annual health checkup. CA-IMT > 1.0 mm was defined as abnormal IMT. Plaque stability was measured by ultrasound examination based on the property of the echo. And sdLDL-C levels were detected by LipoPrint system. Multivariate logistic regression analysis was performed to identify factors associated with CA-IMT and carotid plaque.Results: The abnormal IMT group had significantly higher sdLDL-C levels than control group (p < 0.0001). And sdLDL-C levels were significantly positively correlated with IMT value (r = 0.1396, p = 0.0021) and presence of carotid plaque (r = 0.14, p = 0.002) in the subjects with abnormal IMT. In addition, subjects with higher levels of sdLDL-C (r = 0.11, p = 0.035) tended to have unstable CAP. After adjustment for age, gender and blood glucose, sdLDL-C level was an independent risk factor of the presence of CAP (OR = 1.59, 95% CI: 1.02-1.83, p = 0.034) in subjects with abnormal IMT.Conclusion: SdLDL-C is an independent risk factor of the occurrence of CAP in the Chinese subjects with abnormal IMT. Our findings provide supporting evidence that sdLDL-C might be an alternative way to predict CVD in early stage. [ABSTRACT FROM AUTHOR]

Background: As one of the oldest traditional dyes, people worldwide have used natural indigo for centuries. Local people have unique knowledge about indigo identification, which is crucial for indigo quality control and determining the dyeing effects. However, such traditional knowledge is rarely documented and explained. Therefore, the aims of this study were to document and assess the traditional knowledge used by local people when identifying natural indigo paste as well as quantitatively explore the characteristics and material basis of such traditional knowledge. Method: Three field surveys were conducted between 2019 and 2020. A total of 283 traditional indigo-paste artisans were interviewed in Guizhou, Yunnan, and Fujian Provinces. The frequency of citation, mention index, and fidelity level of each indigo-paste quality criterion were calculated to determine the most commonly used, recognized, and important quality criteria. To explore the characteristics and material basis of the traditional knowledge, we analyzed 21 indigo-paste samples using high-performance liquid chromatography with diode-array detection (HPLC-DAD), pH, and particle size analyses. Results: Local people possess unique knowledge to identify natural indigo. Based on this knowledge accumulated over thousands of years, four criteria (color, taste, touch, and dyeing ability) were chosen by local people, and using these criteria, nature indigo was divided into five quality grades. The best quality indigo paste was judged according to the following folk criteria: dark blue in color with a purple-red luster; smooth and difficult to wipe off; having a sweet, bitter or spicy taste; and easy cloth dyeing. Additionally, the higher the contents of indigo and indirubin—especially indirubin—the better is the quality of the indigo paste. Within the pH range of 9–12, high-quality indigo-paste was more acidic. There was no significant relationship between particle size and quality. Conclusion: The ancient methods used by local people for identifying natural indigo are comprehensive and unique. By documenting the various folk quality criteria and conducting quantitative analyses, this study revealed the importance of indirubin and pH for assessing the quality of indigo paste. These findings differ from existing quality standards for synthetic indigo. Amid rapid modernization, traditional knowledge remains invaluable as a world heritage of humanity that warrants preservation. [ABSTRACT FROM AUTHOR]

Calcic vertisol is a typical kind of low-yield field with a total area of about 4 million hm2 in China. Calcareous concretion with particle size larger than 2 mm has been one of the representative characteristics of calcic vertisol. The limitation of soil available water is an important reason for crop failure in this region. Therefore, the curve of soil water retention dominates the estimation of available water content. However, most studies focused on the effects of calcareous concretion on soil water retention of calcic vertisol mainly under laboratory conditions. It is lacking that under field conditions. In this study, both field surveys and laboratory experiments were conducted to explore the effect of calcareous concretion distribution in 0-1 m soil profile on soil water retention. Firstly, the spatial distribution of calcareous concretion was investigated in the study plot with 150 m length, 50 m width, and 1 m depth. After then, soil profiles (0-1 m soil depth) were chosen to divide into 5 layers with a 20 cm interval. Disturbed and undisturbed soil samples were collected in each layer. Physicochemical properties were evaluated to measure the distribution of soil particle size, size and content of calcareous concretion, bulk densities of soil, and calcareous concretions. Meanwhile, the curves of soil water retention were determined using high speed centrifuge. A pressure plate method was conducted to measure water retention curves in calcareous concretion. The results showed that the mass contents of clay, silt, and sand were 30.56%-39.75%, 39.88%-45.34%, and 18.67%-24.45%, respectively, which belonged to silty clay soil in the classification standard of the United States Department of Agriculture (USDA). Clayey particles decreased, but sandy particles increased significantly with the increase of soil depth. Calcareous concretion was mainly distributed in the soil depth of >20-100 cm, where the content and size increased as soil depth increased. Calcareous concretions content in the surface soil (0-20 cm) was very low (with mass content 0.02%), where only a few calcareous concretions of 2-5 mm were discovered. The maximum content of calcareous concretion was detected at > 80-100 cm (up to 11.42%), where the calcareous concretion content was 8.04% in the size of >8-30 mm. Soil bulk density ranged from 1.23-1.61 g cm-3. The densities of calcareous concretions were 2.01, 2.21, and 2.23 g cm-3 with the size of 2-5 mm, >5-8 mm, and >8-30 mm, respectively. Soil bulk density increased along with the calcareous concretion content increasing. Water retention curves of soil and calcareous concretion were well fitted by the van Genuchten model, with the determination coefficient larger than 0.95. The saturated water content of surface soil (0-20 cm) was significantly higher than that of 20-100 cm soil. Nevertheless, the Gravitational-water content in the surface soil (0-20 cm) was much larger than that in the soil of > 20-100 cm, which was related to macropores formed during tillage. In the subsurface (>20-100 cm), soil gravitational-water content and available water-holding capacity increased with the increase of soil depth, but the field capacity and wilting point decreased. Calcareous concretion maintained a non-negligible amount of water, 0.25, 0.22, and 0.20 cm3 /cm3 in the particles with the size of 2-5 mm, >5-8 mm, and >8-30 mm, respectively. But the water-holding capacities of calcareous concretion were significantly lower than that of soil. The effects of calcareous concretion on water-holding capacity mainly occurred in the subsurface soil. Soil saturated water content, field capacity, and wilting point decreased with increasing calcareous concretion. Interestingly, calcareous concretion content was positively correlated with the soil sand content, but negatively correlated with the soil clay content. Calcareous concretion can bind soil particles together to prevent sand weathering, and thereby effectively improve soil texture. More calcareous concretion led to higher sand contents, and thus increased the available water-holding capacity in soil. This finding can provide a theoretical basis to accurately assess the soil water-holding capacity in calcic vertisol for precision irrigation and high crop productivity. [ABSTRACT FROM AUTHOR]

With speeding up urbanization in China, it is important to understand the vertical distribution characteristics of outdoor particulate matter concentrations of high-rise buildings. A high-rise building at different heights (1st, 7th, 11th, 17th, 23th, and 27th floors) in a university in Xi'an was tested and analyzed in this paper. Test time was 8:00, 12:00, 15:00, 15:00 and 22:00, respectively. The results showed that the concentration of each particulate matter changed the same trend roughly with the increase of vertical height at 8:00 and 22:00, as well as at 15:00 and 18:00. While the mass concentration of each particle showed a trend of first increased, then decreased and next then increased with the height increased when the time was 12:00. It caused by the inverse temperature. The particles between 0 and 1.0 μm accounted for more than 99.4% during the testing. There were mainly small particles in the atmosphere. PM1.0/PM10 and PM2.5/PM10 all showed a trend of first decreased and then increased at different vertical height. The highest points of PM2.5 /PM10 and PM1.0 /PM10 increased by 9.63% and 8.2% respectively from the lowest points, and the ratio was the highest at 15:00. At the same time, outdoor meteorological conditions would also affect the concentration distribution of particulate matters. This paper provides a reference for the development of high-rise buildings and the effective control of particulate matter concentration in high-rise buildings. [ABSTRACT FROM AUTHOR]

RP-3 is the most popular aviation fuel in China and its soot emission raises serious concern. The current study analyzed the soot precursors of RP-3 and n-dodecane in laminar flame, and integrated the corresponding poly-aromatic hydrocarbons (PAHs) growth mechanisms with popular RP-3 and n-dodecane oxidation mechanisms to improve the soot formation prediction for both fuels. The sizes of soot precursors were determined by the fringe lengths of soot particles. At dimensionless height DH = 0.25 of RP-3 and DH = 0.50 of n-dodecane, the geometric mean fringe lengths of RP-3 and n-dodecane are measured to be 0.67 nm and 0.64 nm respectively, which approximate to the size of the five-ringed (A5) poly-aromatic hydrocarbon. An A5 growth mechanism was then added on both popular RP-3 and n-dodecane oxidation mechanisms respectively. The base oxidation mechanisms for both fuels only contain the mono-aromatic hydrocarbons formation and benzene was treated as soot precursors in simulation. After validation by the ignition delay time and flame speed in literature, the combined mechanisms were then used to simulate the soot property and validated by the measured primary particle diameter. The simulation results suggested that the computed soot precursor concentrations of the combined mechanisms are smaller than that of the base mechanism. The combined mechanisms enhance the soot nucleation process which increases the primary particle number density prediction, and weaken the soot growth process which decreases the soot volume fraction prediction for both fuels. Eventually, the proposed combined mechanisms including the large PAHs growth provide a better agreement with the measured primary particle diameter. • The soot precursors of RP-3 and n-dodecane in laminar flame were analyzed by HRTEM images of soot particles. • The five-ringed PAH growth mechanisms were added on popular RP-3 and n-dodecane oxidation mechanisms. • The combined mechanisms enhance the prediction ability of the primary particle number density. • The simulated primary particle diameters by combined mechanisms agree well with the measured primary particle diameters. [ABSTRACT FROM AUTHOR]

The influence of sub-grid particle formation (SGPF) in point source plumes on aerosol particles over eastern China was firstly illustrated by implementing a SGPF scheme into a global-regional nested chemical transport model with aerosol microphysics module. The key parameter in the scheme was optimized based on the observations in eastern China. With the parameterization of SGPF, the spatial heterogeneity and diurnal variation of particle formation processes in sub-grid scale were well resolved. The SGPF scheme can significantly improve the model performance in simulating aerosol components and new particle formation processes at typical sites influenced by point sources. The comparison with observations at Beijing, Wuhan, and Nanjing showed that the normal mean bias (NMB) of sulfate and ammonium could be reduced by 23 %-27 % and 12 %-14 %, respectively. When wind fields were well reproduced, the correlation of sulfate between simulation and observation can be increased by 0.13 in Nanjing. Considering the diurnal cycle of new particle formation, the SGPF scheme can greatly reduce the overestimation of particle number concentration in nucleation and Aitken mode caused by fixed-fraction parameterization of SGPF. In the regional scale, downwind areas of point source got an increase of sulfate concentration by 25 %-50 %. The results of this study indicate the significant effects of SGPF on aerosol particles over areas with the point source and necessity of reasonable representation of SGPF processes in chemical transport models. [ABSTRACT FROM AUTHOR]

Because anthropogenic sulfur dioxide (SO 2) emissions have decreased considerably in the last decade, PM 2.5 pollution in China has been alleviated to some extent. However, the effects of reduced SO 2 on the particle number concentrations and subsequent contributions of grown new particles to cloud condensation nuclei (CCN) populations, particularly at high altitudes with low aerosol number loadings, are poorly understood. In contrast, the increase in provincial forest areas in China with rapid afforestation over the last few decades expectedly increases the biogenic emissions of volatile organic compounds and their oxidized products as nucleating precursors therein. In this study, we evaluated the campaign-based measurements made at the summit of Mt. Tai (1534 m a.s.l.) from 2007 to 2018. With the decrease in SO 2 mixing ratios from 15 ± 13 ppb in 2007 to 1.6 ± 1.6 ppb in 2018, the apparent formation rate (FR) of new particles and the net maximum increase in the nucleation-mode particle number concentration (NMINP) in the spring campaign of 2018 was 2- to 3-fold higher than those in the spring campaign of 2007 with almost the same occurrence frequency of new particle formation (NPF) events. In contrast, the campaign-based comparison showed that the occurrence frequency, in which the maximum geometric median diameter of the grown new particles (Dpgmax) was > 50 nm, decreased considerably from 43 %–78 % of the NPF events before 2015 to < 12 % in 2017–2018. Assuming > 50 nm as a CCN threshold size at high supersaturations, the observed net CCN production decreased from 3.7 × 10 3 cm -3 (on average) in the five campaigns before 2015 to 1.0 × 10 3 cm -3 (on average) in the two campaigns in 2017–2018. We argue that the increases in the apparent FR and NMINP are mainly determined by the availability of organic precursors that participate in nucleation and initial growth, whereas the decrease in the growth probability is caused by the reduced emissions of anthropogenic precursors. However, large uncertainties still exist because of a lack of data on the chemical composition of these smaller particles. [ABSTRACT FROM AUTHOR]

Tracing the aging progress of soot particles during transport is highly challenging. An Asian dust event could provide an ideal opportunity to trace the continuous aging progress of long-range-transported soot particles. Here, we collected individual aerosol particles at an inland urban site (T1) and a coastal urban site (T2) in China and a coastal site (T3) in southwestern Japan during an Asian dust event. Microscopic analysis showed that the number fraction of soot-bearing particles was 19 % and 16 % at T1 and T2 in China but surprisingly increased to 56 % at T3 in Japan. The dominant fresh soot (71 %) at T1 became partially embedded (68 %) at T2 and fully embedded (84 %) at T3. These results indicated that the tiny soot particles had lower deposition than other aerosol types and became more aged during the transport from T1 to T3. We quantified soot morphology using the fractal dimension and found an increasing trend of 1.65 at T1, 1.84 at T2, and 1.91 at T3. Furthermore, we found that the morphology compression of the soot aggregations was associated with secondary coating thickness and relative humidity. A unique mixing structure where multi-soot particles scattered in organic coatings instead of the sulfate core in individual core-shell particles was observed at T3 after the crossing of the East China Sea. The study provides understanding for important constraints of the soot morphological effects and provides a possible aging scale along with their transport pathway. These new findings will be helpful to improve optical calculations and regional climate modeling of soot particles during their transport in the atmosphere. [ABSTRACT FROM AUTHOR]

Though China has witnessed substantial particular matter pollution mitigation owing to the strict emission control in recent years, the frequency of haze events with low visibility is not improved as much as expected, especially in cold seasons. Here, 6‐year wintertime observations, satellite retrievals, a thermodynamic model, and theoretical calculation were integrated to better understand the complex influence of aerosol chemical composition and hygroscopic behaviors on visibility impairment. We found that the proportion of nitrate in aerosol mass concentration increased by approximately 10% from 2013 to 2018. Such a transition in aerosol chemical compositions together with increasing ambient humidity in past years jointly enhanced aerosol extinction efficiency, and the elevated proportion of nitrate played an increasingly critical role after 2017. The increased aerosol extinction efficiency is responsible for the less improved visibility despite large decrease in aerosol mass concentrations in eastern China. Plain Language Summary: Atmospheric aerosol degrades regional visibility as a result of light extinction, which is highly linked with aerosol chemical composition and particle size growth in humid environment. Due to a much sharper drop of sulfur emission than nitrogen emission in China, aerosol has become increasingly nitrate‐dominant. The transition in aerosol chemical compositions together with increasing ambient humidity in past years may jointly alter aerosol hygroscopic behaviors and enhance aerosol extinction efficiency. In consequence, although substantial mitigation of aerosol pollution has been achieved in recent years, hazy days with low visibility still frequently occur in eastern China. Key Points: Visibility improvement is not obvious in eastern China despite strict emission controlNitrate proportion in PM2.5 has substantially increased due to unbalanced precursor emission controlIncreased nitrate proportion and humidity enhance aerosol hygroscopicity and extinction efficiency [ABSTRACT FROM AUTHOR]

本文旨在探討在線上互動中實習教師與學生句末語氣詞使用情形。結果顯示,教師句末語氣詞的使用比例為37%,明顯高於學生的15%。教師使用頻率最高的為「嗎」, 佔教師出現語氣詞總數的58%, 學生使用頻率最高的為「嗎」、「啊」,各佔學生出現語氣詞總數的36%。本文亦對兩岸教師、母語為華語與非華語之教師以及家中使用與不使用華語之學生的句末語氣詞使用頻率差異進行了比較。最後, 輔以說話者的身分類別進行綜合比較, 發現教師身分對華語母語教師的語氣詞使用類型及頻率皆有影響。本文分析真實教學互動情境中出現的語氣詞研究結果, 不僅能為現有兩岸句末語氣詞研究的語料佐證, 亦能實際應用於華語教學。 The purpose of this study is to explore the use of Mandarin utterance-final particles in online teacher-student interactions. The interactions were carried out by 15 preservice teachers who were graduate students at the Department of Chinese as a Second Language and 6 learners of Chinese as a second language in Singapore. After four online-interaction sessions (24 classes in total), we tagged utterance-final particles in the sentences of the corpus produced from conversation between the teachers and students. The results show that utterance-final particles spoken by students are Ma (嗎) > A (啊) > O (喔) > Ba (吧) > Ye (耶) > Ne (呢) = La(啦) > Wa(哇), in the order of decreasing frequency. Yo (唷) or Ma (嘛) did not appear in the students' speech. The utterance-final particles were used in 15% of the total number of turns by the students, and their most frequently used particles were Ma (嗎) and A (啊), each accounted for 36% of their total number of utterance-final particles. Utterance-final particles produced by the preservice teachers are Ma (嗎) > Ne (呢) >A (啊) > O (喔) > Ba (吧) > Ye (耶) > Ma (嘛) > Luo (囉) > La(啦) = Wa(哇) > Yo (唷), in the order of decreasing frequency. The utterance-final particles were used in 37% of the total number of turns by the preservice teachers, and their most frequently used utterance-final particle was Ma (嗎), which accounted for 58% of their total number of utterance-final particles. This study also looked into the factors that may influence the use of utterance-final particles, such as regional Mandarin variations (Taiwan vs. Mainland China), preservice teachers' primary language (Mandarin or other languages), where the second language learners are originally from, and whether Chinese heritage students speak Mandarin at home. The rate using utterance-final particles of Taiwanese teachers was 8% higher than that of Mainland Chinese teachers, and this result agrees with our general impression on utterance-final particles occur more frequent in Taiwanese Mandarin. The heritage students who speak Mandarin at home used utterance-final particles 2% more than those who do not. The teachers whose primary language is Mandarin used 11% more of the utterance-final particles than those who speak other languages. In addition, the rate using utterance-final particles of Taiwanese teachers was 8% higher than that of Mainland Chinese teachers, and this result agrees with our general impression on utterance-final particles occur more frequent in Taiwanese Mandarin. In this study, we realized that various factors may affect the frequency of using specific utterance-final particle, such as the power and solidarity between the speaker and the hearer, such as teacher to student. Additionally, our result shows that language background also plays a role in how a speaker uses utterance-final particles. In our future research, we will further analyze the factors that determine the frequency of Mandarin utterance-final particles. [ABSTRACT FROM AUTHOR]

To build a widely applicable modelling method for maize seed particles, nine major maize varieties in mainland China are analysed. According to the analysis, maize seed particles can be simplified into 5 shapes, i.e. , horse-tooth shape, truncated triangular pyramid shape, ellipsoid cone shape, spheroid shape and irregular shape, and there is a certain functional relationship between the characteristic sizes of each shape of maize seeds. On this basis, the particle models of four shapes of seeds with different accuracy are built using the multi-sphere method. Meanwhile, artificial roughness values are used for evaluation of the filling accuracy of the multi-sphere model, and the calculation formula of the artificial roughness is given. An analysis of the multiple contacts in the multi-sphere model is also performed. Based on the above works, the feasibility of the modelling method of the maize seed proposed in this paper is verified by comparing the experimental and simulation results of bulk density, angle of repose and "self-flow screening". These results show that, when the artificial roughness values of the horse-tooth seed model, the truncated triangular pyramid seed model and the ellipsoid cone seed model are approximately 0.7 or less than 0.7 and the number of filling spheres of the spheroid seed model is no less than 9, then the corresponding simulation results are close to the experimental results. In addition, by comparing the results of the Hertz-Mindlin (no-slip) contact model and the HM-new-restitution contact model, it is also proven that the multiple contacts have less impact on the movement of an assembly of the particle models of maize seeds proposed in this paper. Unlabelled Image • Maize seed particles can be simplified into five shapes. • The location and radius of the sub-spheres as a function of the characteristic sizes. • The artificial roughness of particle models of maize seed is defined and calculated. • The artificial roughness, the size and shape of the seed model influence on results. • No impact of the multi-contact on the movement of an assembly of particle models. [ABSTRACT FROM AUTHOR]

In this study, a cruise campaign was conducted over marginal seas in China to measure the concentrations of condensation nuclei (Ncn), cloud condensation nuclei (Nccn) and other pollutants from day of year (DOY) 110 to DOY 135 of 2018. The ship self-emission signals were exhaustively excluded, and the mean values of Nccn during the cruise campaign were found to slightly increase from 3.2±1.1×103 cm -3 (mean ± standard deviation) at supersaturation (SS) of 0.2 % to 3.9±1.4×103 cm -3 at SS of 1.0 %, and the mean value for Ncn was 8.1±4.4×103 cm -3. Data analysis showed that marine traffic emissions apparently largely contributed to the increase in Ncn in the daytime, especially in the marine atmospheres over heavily traveled sea zones; however, the fresh sources made no clear contribution to the increase in Nccn. This finding was supported by the quantitative relations between Ncn and Nccn at SS = 0.2 %–1.0 % against the mixing ratios of SO2 in the ship self-emission plumes – i.e., a 1 ppb increase in SO2 corresponded to a 1.4×104 cm -3 increase in Ncn but only a 30–170 cm -3 increase in Nccn , possibly because of abundant organics in the aerosols. Smooth growth can be observed in the marine-traffic-derived particles, reflecting aerosol aging. The estimated hygroscopicity parameter (κ) values were generally as high as 0.46–0.55 under the dominant onshore winds, suggesting that inorganic ammonium aerosols likely acted as the major contributor to Nccn largely through aerosol aging processes of decomposing organics. Moreover, the influences of the new transported particles from the continent on the Ncn and Nccn in the marine atmosphere were investigated. [ABSTRACT FROM AUTHOR]

In the application of the physical iterative method to retrieve millimeter-wave radar liquid water content (LWC) and liquid water path (LWP), particle parameter scheme is the main factor affecting retrieval performance. In this paper, synchronous measurements of an airborne millimeter-wave radar and a hot-wire probe in stratus cloud are used to compare the LWC retrievals of the oceanic and continental particle parameter scheme with diameter less than 50µm and the particle parameter scheme with diameter less than 500µm and 1500µm (scheme 1, scheme 2, scheme 3, and scheme 4, respectively). The results show that the particle parameter scheme needs to be selected according to the reflectivity factor when using the physical iterative method to retrieve the LWC and LWP. When the reflectivity factor is less than - 30dBZ, the retrieval error of scheme 1 is the minimum. When the reflectivity factor is greater than -30dBZ, the retrieval error of scheme 4 is the minimum. Based on the reflectance factor value, the LWP retrievals of scheme 4 are closer to the measurements, the average relative bias is 5.2%, and the minimum relative bias is 4.4%. Compared with other schemes, scheme 4 seems to be more useful for the LWC and LWP retrieval of stratus cloud in China. [ABSTRACT FROM AUTHOR]

This study examined the development of a digital pulse analyzer (DPA) used for obtaining the pulse height distribution (PHD), pulse width distribution (PWD), and interval time distribution (ITD) simultaneously by processing output signals from an optical particle counter (OPC). The characterization was performed by testing the response of the DPA as a function of its input frequency and pulse height using dummy signals from a signal generator (model DG1022, Rigol Technologies Inc., People's Republic of China) and actual OPC signals (Model KC-03, Rion Co. Ltd, Japan). Polystyrene latex particles of various sizes yielded by a scanning mobility particle sizer were used during the calibration of the DPA. It was found that the geometric mean of the PHDs was in accordance with Mie theory and could be used for converting pulse height into data which represents the size of particles. Furthermore, by using the PWD and ITD, we could estimate the viewing volume and dead time of the OPC. The DPA could successfully discriminate particles from baseline noise or voltage spikes by applying a novel algorithm to detect pulses based on the pulse area (integral of the voltage–time curve). The results showed that the ranges of particle diameter, viewing volume, and dead time measured by the OPC-DPA system were 0.2–1 µm, (0.78 ± 0.09) mm3, and (45.9 ± 12.6) µs, respectively. The new algorithm can be applied to pulse height analyzers in general, in the measurement of aerosol particles or scintillator-based particle detectors. [ABSTRACT FROM AUTHOR]

Based on the analysis of particle size mechanical composition and parameter distribution of surface sediments in the Hobq Desert (HD), the Ulan Buh Desert (UBD) and the northern part of the Mu Us Desert (MUD) in western Inner Mongolia, and combining the sedimentary environment discrimination method and the particle size lognormal fitting method, this research compares and explores the particle size characteristics and the significance of sensitive components in the sedimentary environment to the provenance in the three deserts. The results are shown as follows: (1) Sediment samples in the HD are dominated by fine sand (48.9%), in the UBD by fine sand and medium sand (41.10% and 42.90%, respectively) and in the MUD by medium sand (41.62%). (2) σ 1 and S K 1 in the HD and the UBD are well sorted and symmetric, but are averagely sorted and show highly positive skewness in the MUD. (3) The sediment samples in the HD and the UBD are mainly aeolian sediments, with lacustrine sediments being secondary. By contrast, the sediment samples in MUD is largely made up of lacustrine deposits. (4) By fitting the particle size frequency curves of all samples, five components, namely C1, C2, C3, C4 and C5 ranging from fineness to coarseness, are obtained. It is also indicated that the sediments in the study area do not undergo a wide range of mixing, but mainly experience in situ sedimentation. The most of these sediments may belong to lakeshore deposits that have been modified by wind for a long time, and are accompanied by long-distance westerly dust, weathered debris from bedrock, and active paleosand dunes of riverbed sediments. [ABSTRACT FROM AUTHOR]

Objectives: The aim of this study was to determine the lag between exposure to air pollutants and changes in human eosinophil counts.Material and Methods: This was a retrospective study employing 246 425 physical examination records dated December 2013 - December 2016 from Chengdu, China. The authors determined the prevalence of individuals with eosinophil counts above the normal reference range each day. A distributed lag non-linear model was used to evaluate the lagged effect of each air pollutant on eosinophil counts. The lagged effects of each air pollutant were counted and presented with smoothing splines.Results: The effects of air pollutants such as particulate matter (PM2.5, aerodynamic diameters <2.5 μm; PM10, aerodynamic diameters <10 μm), nitrogen dioxide (NO2) and ozone (O3) were evaluated. In women, the effects of PM2.5 (RR = 1.154, 95% CI: 1.061-1.255) and PM10 (RR = 1.309, 95% CI: 1.130-1.517) reached the maximum values on lag day 0. In men, there was no significant effect of PM2.5, but significant effects of PM10 were found for lag days 20-28. The effects of NO2 and O3 on eosinophils were not statistically significant for either gender.Conclusions: The air pollutants of PM10 have a significant effect on human eosinophils for both women and men, but with different temporal patterns, with women showing a lag of 0-5 days and men showing a lag of 20-28 days. In addition, PM2.5 was significant for women with a lag of 0-3 days but it was not significant for men. Int J Occup Med Environ Health. 2020;33(3):299-310. [ABSTRACT FROM AUTHOR]

Objective: The aim of this study is to compare the efficiency of different separation techniques for extracting synovial tissue-derived exosomes. Methods: The synovial tissue discarded during knee arthroscopy or total knee arthroplasty surgery was collected from the Third Affiliated Hospital of Beijing University of Chinese Medicine. Ultracentrifugation (UC), filtration combined with size exclusion chromatography (SECF), and 8% polyethylene glycol (PEG) were used to extract synovial tissue-derived exosomes. Transmission electron microscopy (TEM), nanoparticle tracer analysis (NTA), and Western Blot (WB) were used to detect the morphology, particle size, and biomarker proteins (CD9, CD63, Flotillin-1, and calnexin) of exosomes. Results: The extracts of enriched round and discoid vesicles were successfully extracted with UC, SECF, and PEG. The results of TEM have shown that all three extraction methods can extract circular or elliptical vesicles with disc- and cup-shaped structures from the synovial tissue, with the diameter is about 30–150 nm. NTA suggested the main peaks of three groups of exosomes are around 100–120 nm, and the concentration of the three groups of exosomes was greater than 1 × 1010/ml. The results of WB showed that three positive protein markers (CD9, CD63, and Flotillin-1) were highly expressed in the suspension extracted by the three methods and low in the synovial tissue. However, the negative protein (calnexin) was highly expressed in synovial tissues and PEG group, while low in UC and SECF group. Conclusion: Morphology, particle size, and labeled protein marker detection confirmed that UC, SECF, and PEG can extract exosomes derived from synovial tissue; UC and SECF are more recommended for the extraction of synovial tissue-derived exosomes, which provides a methodological basis for studying the function and mechanism of synovial tissue exosomes in the future. [ABSTRACT FROM AUTHOR]

Although satellite-based approaches have been developed and adopted for estimating the concentration of fine particulate matter (PM 2.5) with promising accuracy, few studies have considered mass concentration and particle radius simultaneously, even though particle size is significant for human health impacts. We developed a satellite-based PM 2.5 retrieval method using optical-mass relationships via aerosol microphysical characteristics. Satellite data from the MODerate resolution Imaging Spectroradiometer (MODIS) instrument, combined with parameters from meteorological reanalysis, were processed to calculate particle radii and retrieve PM 2.5 mass concentrations over China in 2017. Our study is the first to identify the spatial pattern of mean PM 2.5 radius over China, which was validated against observations from AERONET (RMSE = 0.11 μm). Mean particle size over eastern China is smaller than in the west, depicting a clear bifurcation across the country, especially in summertime. This finding is attributed to variations in topography, meteorology, land use and population density, which affects the properties of emitted aerosols as well as their fate and transport. A statistically significant correlation (R = 0.82) was observed between estimated and measured annual PM 2.5 , with RMSE = 9.25 μg/m3, MAE = 6.98 μg/m3, MBE = −1.98 μg/m3 and RPE = 17.69% (N = 1270). The spatiotemporal distributions of resulting PM 2.5 are consistent with previous findings, indicating the effectiveness and applicability of our method. Our approach quantifies PM 2.5 mass concentrations without introducing regionally-specific fitting parameters, which can be efficiently applied across various spatial and temporal domains. [ABSTRACT FROM AUTHOR]

The size distribution and concentration of atmospheric aerosol particles are important parameters that characterize the physical and optical properties of aerosols. Understanding the spectral distribution of atmospheric particles is fundamental for studying particulate pollution. Based on observational data acquired by an aerodynamic particle sizer APS-3321 and a laser dust meter LD-5 from September 2017 to July 2018, the temporal evolution of particle size distribution and concentration of aerosols were studied at the North Minzu University in Yinchuan (38°29'52"N 106°06'28"E), China. By cluster analysis of particle surface area distribution in different weathers, seven clusters were obtained and discussed. The experimental results showed that the particle number and mass concentrations were different in the four seasons of the year. Compared with the unimodal distribution of the particle number concentration and the doublet mass concentration distribution in sunny weather conditions, there were great differences in the particle spectrum distribution in haze, snowfall, and dusty weather conditions. The particle surface area distributions of the seven clusters were clearly different from each other and influenced by meteorological conditions. Additionally, the PM2.5 value has a relationship with the meteorological elements. The research is helpful to reveal the formation mechanism and source of aerosols in Yinchuan, China. [ABSTRACT FROM AUTHOR]

The sequential extraction method was used to determine the fraction of arsenic (As) in different-sized particulate matters (PMs) (i.e., PM2.5, PM10, and total suspended particles (TSP)). Samples were collected from Baoding, a typical medium-sized city with the serious haze pollution in China. The bioavailabilities of As in the samples were estimated based on the fraction results. A large percentage of fine particles were detected in TSP, with the average PM2.5/PM10 and PM10/TSP ratios all above 0.69. The total concentrations of As in PM2.5, PM10, and TSP samples were in the range of 4.5–296.4, 14.1–708.0, and 32.8–798.0 ng m−3, respectively. The mass percentages of As in PM2.5, PM2.5–10, and PM10–100 were calculated; the results indicated that As tended to concentrate in fine particles. PM-bound As mainly presented in the nonspecifically sorbed fraction (F1) during all of the sampling periods. The percentages of F1-As and bioavailability of As were higher in PM2.5, followed by PM10 and TSP. By contrast, the residual fraction (F5-As) contents declined in the order of TSP > PM10 > PM2.5. Significant differences in the speciation and bioavailability of As in different-sized PMs were found, and the influence of particle size on the speciation and bioavailability of As in PMs was verified. Fine particles adsorbed more As with higher bioavailability, and potentially led to more serious adverse effects on human health than the larger ones. [ABSTRACT FROM AUTHOR]

Ambient submicron particles (PM 1) exert significant impacts on visibility degradation during severe pollution episodes of urban China. The U.S. IMPROVE algorithms are widely used for assessing the extinction effect of atmospheric aerosols, but only suitable for fine particulate matter. A proper algorithm for PM 1 extinction estimation is lacking and becomes urgent, especially after the online measurement of PM 1 species is routine by aerosol mass spectrometers. Here we conducted three-month in-situ measurements to explore mass scattering efficiencies (MSE) of PM 1 major species at a supersite of eastern China. Results indicated that MSEs of ammonium sulfate and nitrate increase quickly and then keep stable with the mass accumulation, while those of organic matter keep at ∼5.5 m2/g but with a large vibration in the whole mass range. The algorithm for reconstructing PM 1 dry scattering coefficient was derived from the integral of the variation patterns for the three PM 1 species. The algorithm was then validated and compared with other empirical algorithms through separate field measurements. Good correlations between the reconstructed and measured dry scattering coefficient were observed with R square higher than 0.9 and slope of 1.01–1.05, indicating that the reconstructed algorithm can predict the dry scattering coefficient well based on PM 1 chemical composition measurements in urban China. Our study is expected to provide observed insights on the variation of MSE in the wide mass range especially in the high region, as well as accurate formulas for ambient PM 1 dry scattering apportionment. Image 1 • The variations of mass scattering efficiency (MSE) for PM 1 species were investigated. • MSEs increased from 1 to 6 m2/g as the particle size shifted from 200 nm to 700 nm. • The algorithm for scattering coefficient of ambient PM 1 were reconstructed. [ABSTRACT FROM AUTHOR]

• The desorption procedure was divided into five stages, including thirteen substages. • Many closed pores in anthracite are opened during progressive pulverization. • Influencing factors of compositional shift are temperature, time, and particle size. • High concentrations of CO 2 and C 2+ in closed pores are related to the sealing effect. • Pressure increases in closed pores may retard C 2+ cracking at high temperatures. Minimal attention has been paid to the factors influencing compositional shifts in residual gas during the desorption process from coal. Two anthracite samples were collected from the Zhina Coalfield in China to study compositional shifts in residual gas. The entire desorption process was divided into five stages, comprising thirteen substages. Low-pressure N 2 adsorption tests showed that mesopore and macropore volumes and surface areas increased continuously as the particle size of pulverized coal decreased. The increase in porosity with decreasing particle size is attributable to the existence of many closed pores in the coal. The residual gas contents of the two samples were 8.34 and 7.22 cm3/g ("as-received" basis). The desorption rate of residual gas gradually declined with time in a 95 °C thermostatic water bath. Measured concentrations of the chemical gas components CH 4 , C 2+ , N 2 , and CO 2 show distinct variations during the desorption process. The factors influencing compositional shifts in residual gas are ambient temperature, heating time, and pulverized coal particle size. N 2 concentrations were highest during the pulverization process and relatively low during the heating process, which is in contrast with the variation trend of C 2+ and CO 2 concentrations. CH 4 and N 2 concentrations decreased steadily with heating time in a 95 °C thermostatic water bath, whereas C 2+ and CO 2 concentrations showed the opposite trend. This is because C 2+ and CO 2 have stronger adsorption affinities than CH 4 and N 2 do, and a large proportion of N 2 and CH 4 could desorb preferentially from coal. C 2+ and CO 2 concentrations increased with decreasing coal particle size, whereas CH 4 and N 2 concentrations showed the opposite trend. Relatively high concentrations of CO 2 and C 2+ in closed pores may be related to the sealing effect of closed pores, which prevents the escape of early generated products. In addition, increased pressure in closed coal pores should retard C 2+ cracking at high temperatures. Thus, it is necessary to focus on the compositional shifts in residual gas and its influencing factors. Failure to account for these aspects may lead to typical analytical errors, which will propagate in the assessment of CH 4 abundance in coalbeds. [ABSTRACT FROM AUTHOR]

To exploit the resolving ability of rare earth element and yttrium (REY) in resuspension binary mixing model, and discover potential new REY-related resuspension proxy, this preliminary research studied the geochemical signature of REY in different Jiaozhou Bay samples including surficial/core sediments and settling trap-collected particles. Close quantitative relation for bulk concentration in particles, sediments and fine-grained fraction of major river sediments around the Yellow Sea, approved the priority contribution of catchment detrital materials. Moreover, common characteristics occurred for compartment-specific partitioning REY signatures in six operated-defined fractions, and multiple REY normalization pattern indexes (i.e. Y/Ho divergence, and Ce/Eu anomalies). All constrain the application of REY in resuspension discrimination of marginal shallow seas. However, linearity with different slopes and intercepts were plotted for the MREE bulge index versus HREE/LREE figure in reducible amorphous Fe-oxides fraction, which could provide new discrimination perceptions. • The geochemistry of rare earth element and yttrium were evaluated. • Catchment detrital material is responsible for sinking particle and sediment. • Common features occur for specific partitioning REY signatures and indices. • New separated distribution of MREE bulge versus HREE/LREE was discovered. [ABSTRACT FROM AUTHOR]

Abstract Many observation methods have been employed to monitor the changes in the ecological environment. Marine environment monitoring data have characteristics of complex diversity, high spatial-resolution, high time-frequency, and multi-level free-surface depth. In this study, we constructed a three-dimensional temporal-spatial visualization model to express the spatial-temporal variations using particle system. For the temporal dimension, we visualized the dynamic real-time changes by changing properties such as particle color, displacement, and size by calculating the difference between the data at adjacent points in time in different frames. To achieve high quality dynamic display, we introduced the CUDA (Compute Unified Device Architecture) parallel computing model to realize large-scale particle change visualization. This model reduced the CPU load and significantly improved the frame rate. Moreover, this model provides virtual simulation and user interaction rendering, which can dynamically change the environment data type, rendering mode, drawing profiles, and other functions. Finally, we integrated the model as a system component into China's offshore environmental data monitoring and management platform. Highlights • Continuous process simulation of marine environmental data using particle system. • Extension from coordinate space to continuous spatio-temporal dimension. • Efficient parallel computing of particle attributes based on graphics processing unit. • More simulative rendering strategy for presenting the feature variable typical characteristics. [ABSTRACT FROM AUTHOR]

Abstract Linear and cyclic volatile methylsiloxanes (l-VMS and c-VMS) are man-made chemicals with no natural source. They have been widely used in cosmetics, personal care products, coatings and many other products. As a consequence of their wide use, VMS can be found in different environmental media, as well as in humans. We bought 14 new silicone baking moulds and 3 metallic moulds from the market and used them in different baking experiments. Four of the silicone baking moulds were produced in Germany, two in Italy, four in China, and for the other moulds were no information available. The metal forms were all produced in Germany. VMS were measured in the indoor air throughout the baking process and at the edge and in the center of the finished cakes using a GC/MS system. Additionally, the particle number concentration (PNC) and particle size distribution were measured in the indoor air. The highest median concentrations of VMS were observed immediately following baking: 301 μg/m3 of D7, 212 μg/m3 of D6, and 130 μg/m3 of D8. The silicone moulds containing the highest concentrations of c-VMS corresponded with distinctly higher concentrations of the compounds in indoor air. Using a mould for more than one baking cycle reduced the indoor air concentrations substantially. Samples collected from the edge of the cake had higher concentrations relative to samples from the center, with a mean initial concentration of 6.6 mg/kg of D15, 3.9 mg/kg of D9, 3.7 mg/kg of D12, and 4.8 mg/kg of D18. D3 to D5 were measured only at very low concentrations. Before starting the experiment, an average PNC of 7300 particles/cm3 was observed in the room's air, while a PNC of 140,000 particles/cm3 was observed around the electric stove while it was baking, but this PNC slowly decreased after the oven was switched off. Baking with 4 of the moulds exceeded the German indoor precaution guide value for c-VMS, but the health hazard guide value was not reached during every experiment. Compared to other exposure routes, c-VMS contamination of cake from silicone moulds seems to be low, as demonstrated by the low concentrations of D4 and D6 measured. For less volatile c-VMS > D6 the results of the study indicate that food might play a more important role for daily intake. As a general rule, silicone moulds should be used only after precleaning and while strictly following the temperature suggestions of the producers. Highlights • Volatile methylsiloxanes (VMS) are used in various products like cosmetics • They were analyzed in new silicone baking molds and indoor air during the baking. • Additionally, the finished cake samples were investigated • While baking indoor guidelines were partially exceded • It is essential to use silicone molds only after precleaning [ABSTRACT FROM AUTHOR]

Amine-containing particles were characterized in an urban area of Chongqing during both summer and winter using a single-particle aerosol mass spectrometer (SPAMS). Among the collected particles, 12.7 % were amine-containing in winter and 8.3 % in summer. Amines were internally mixed with elemental carbon (EC), organic carbon (OC), sulfate, and nitrate. Diethylamine (DEA) was the most abundant among amine-containing particles. Wintertime amine-containing particles were mainly from the northwest direction where a forest park was located; in summer, they were from the northwest and southwest (traffic hub) directions. These origins suggest that vegetation and traffic were the primary sources of particulate amines. The average relative peak area of DEA depended strongly on humidity, indicating that the enhancement of DEA was possibly due to increasing aerosol water content and aerosol acidity. Using an adaptive resonance theory neural network (ART-2a) algorithm, four major types of amine-containing particles were clustered: amine–organic carbon (A-OC), A-OCEC, DEA-OC, and A-OCEC aged. The identified particle types implied that amines were taken up by particles produced from traffic and biomass burning. The knowledge gained in this study is useful to understand the atmospheric processing, origin, and sources of amine-containing particles in the urban area of Chongqing. [ABSTRACT FROM AUTHOR]

Aerosol--cloud interactions remain a major source of uncertainty in climate forcing estimates. Few studies have been conducted to characterize the aerosol--cloud interactions in heavily polluted conditions worldwide. In this study, cloud residual and cloud interstitial particles were collected during cloud events under different pollution levels from 22 July to 1 August 2014 at Mt. Tai (1532m above sea level) located in the North China Plain (NCP). A transmission electron microscope was used to investigate the morphology, size, and chemical composition of individual cloud residual and cloud interstitial particles, and to study mixing properties of different aerosol components in individual particles. Our results show that S-rich particles were predominant (78 %) during clean periods (PM2.5<15 µgm-3), but a large number of anthropogenic refractory particles (e.g., soot, fly ash, and metal) and their mixtures with S-rich particles (defined as "S-refractory") were observed during polluted periods. Cloud droplets collected during polluted periods were found to become an extremely complicated mixture by scavenging abundant refractory particles. We found that 76% of cloud residual particles were S-refractory particles and that 26% of cloud residual particles contained two or more types of refractory particles. Soot-containing particles (i.e., S-soot and S-fly ash/metal-soot) were the most abundant (62 %) among cloud residual particles, followed by fly ash/metal-containing particles (i.e., S-fly ash/metal and S- fly ash/metal-soot, 37 %). These complicated cloud droplets have not been reported in clean continental or marine air before. Our findings provide an insight into the potential impacts on cloud radiative forcing from black carbon and metal catalyzed reactions of SO2 in micro-cloud droplets containing soluble metals released from fly ash and metals over polluted air. [ABSTRACT FROM AUTHOR]

Background: Recent studies suggest that ambient air pollution exposure during pregnancy is associated with stillbirth occurrence. However, the results on the associations between ambient air pollutants and stillbirths are inconsistent and little is known about the gestational timing of sensitive periods for the effects of ambient air pollutants exposure on stillbirth.Objective: This study aimed to examine whether exposure to high levels of ambient air pollutants in a Chinese population is associated with an increased risk of stillbirth, and determine the gestational period when the fetus is most susceptible.Methods: We conducted a population-based cohort study in Wuhan, China, involving 95,354 births between June 10, 2011 and June 9, 2013. The exposure assessments were based on the daily mean concentrations of air pollutants obtained from the exposure monitor nearest to the pregnant women's residence. Logistic regression analyses were performed to determine the associations between stillbirths and exposure to each of the air pollutants at different pregnancy periods with adjustment for confounding factors.Results: Stillbirth increased with a 10 μg/m3 increase in particulate matter 2.5 (PM2.5) in each stage of pregnancy, and a significant association between carbon monoxide (CO) exposure and stillbirth was found during the third trimester (adjusted odds ratio (aOR): 1.01, 95% confidence interval (CI): 1.00-1.01) and in the entire pregnancy (aOR: 1.18, 95% CI: 1.04-1.34). Furthermore, an increased risk of stillbirth in the third trimester was associated with a 10 μg/m3 increase in PM10 (aOR: 1.08, 95% CI: 1.04-1.11), nitrogen dioxide (NO2) (aOR: 1.13, 95% CI: 1.07-1.21) and sulfur dioxide (SO2) (aOR: 1.26, 95% CI: 1.16-1.35). However, no positive association was observed between ozone exposure and stillbirth. In the two-pollutant models, PM2.5 and CO exposures were found to be consistently associated with stillbirth.Conclusions: Our study revealed that exposure to high levels of PM2.5, PM10, SO2, NO2 and CO increases the risk of stillbirth and the most susceptible gestational period to ambient air pollution exposure was in the third trimester. Further toxicological and prospective cohort studies with improved exposure assessments are needed to confirm the causal link between air pollutants and stillbirth. [ABSTRACT FROM AUTHOR]

Background: Existing studies exploring the association between low birth weight (LBW) and maternal fine particulate matter (aerodynamic diameter<2.5μm, PM2.5) exposure have presented equivocal results, and one of the possible reasons for this finding might be due to relatively low maternal exposures. In addition, relatively narrow maternal exposure windows to PM2.5 have not been well established for LBW.Methods: We employed a nested matched case-control design among 43,855 term births in a large maternity and child care hospital in Jinan, China. A total of 369 cases were identified, and four controls per case matched by maternal age were randomly selected among those with normal birth weight (n=1,476) from 2014 to 2016. Ambient air monitoring data on continuous measures of PM2.5, nitrogen dioxide (NO2), and sulfur dioxide (SO2) (24-h average concentrations) from 2013 to 2016 were collected from thirteen local monitoring stations. An inverse distance weighting method based on both home and work addresses was adopted to estimate the individual daily exposures to these air pollutants during pregnancy by weighting the average of the twelve nearest monitoring stations within 30km of each 100m×100m grid cell by an inverse squared distance, and then the average exposure concentrations for gestational months, trimesters and the entire pregnancy were calculated. Adjusted conditional logistic regression models were used to estimate the odds ratios (ORs) per 10μg/m3 increment in PM2.5 and by PM2.5 quartiles during different gestational periods.Results: In this study, the estimated mean values of PM2.5, NO2, and SO2 exposure during the entire pregnancy were 88.0, 54.6, and 63.1μg/m3, respectively. Term low birth weight (TLBW) increased in association with per 10μg/m3 increment in PM2.5 for the 8th month [OR=1.13, 95% confidence interval (CI): 1.04, 1.22], the 9th month (OR=1.06, 95% CI: 0.99, 1.15), the third trimester (OR=1.17, 95% CI: 1.05, 1.29), and the entire pregnancy (OR=1.38, 95% CI: 1.07, 1.77) in models adjusted for one pollutant (PM2.5). In models categorizing the PM2.5 exposure by quartiles, comparing the second, third, and highest with the lowest PM2.5 exposure quartile, the PM2.5 was positively associated with TLBW during the 8th month (OR: 1.77, 95% CI: 1.09, 2.88; OR: 1.77, 95% CI: 1.03, 3.04; OR: 1.92, 95% CI: 1.04, 3.55, respectively) and for the 9th month, only association for exposure in the third versus the lowest quartile was significant (OR: 1.91, 95% CI: 1.02, 3.58).Conclusions: The study provides evidence that exposure to PM2.5 during pregnancy might be associated with the risk of TLBW in the context of very high pollution level of PM2.5, and the 8th and 9th months were identified as potentially relevant exposure windows. [ABSTRACT FROM AUTHOR]

Objective: The purpose of this investigation is to present a preliminary clinical experience in transarterial chemoembolization (TACE) with gelatin sponge microparticles (GSMs) for barcelona clinic liver cancer (BCLC) Stage C and large hepatocellular carcinoma (HCC) patients in China.Materials and Methods: Between August 2009 and August 2012, 20 BCLC Stage C HCC patients with tumor size ≥5 cm undergoing GSMs-TACE were retrospectively analyzed. Tumor response was evaluated using modified response evaluation criteria in solid tumors (mRECIST) with enhanced magnetic resonance/computed tomography imaging performed 4-6 weeks after each GSMs-TACE procedure. Kaplan-Meier curves were used to assess overall survival (OS). Complications postprocedure was also analyzed.Results: In this cohort of 20 HCC patients, vascular invasion was present in 8 patients (40%), extrahepatic metastases in 6 patients (30%), and both in 6 individuals (30%). Median tumor size was 9.9 ± 3.2 cm. All procedures were successfully performed with minimal complications. The mean number of TACE per patient was 2.6 sessions (range 1-5). Median OS (mOS) was 14 months for the entire study population. Survival rates at 6 and 12 months were 85% and 73.7%, respectively. According to mRECIST criteria, follow-up images were obtained 6 months after initial GSMs-TACE. Five patients (25.0%) achieved complete response, 8 patients (40.0%) had partial response, 4 (20.0%) had stable disease, and 3 (15.0%) had progressive disease. The objective response rate for TACE was 65%.Conclusions: From our preliminary clinical experience, GSMs-TACE in the treatment of BCLC Stage C and large HCC appears to offer favorable survival and tumor response with low morbidity. However, further prospective studies are required to assess its safety and efficacy. [ABSTRACT FROM AUTHOR]

Background: Numerous studies have found associations between ambient fine particulate matter (PM2.5) and increased mortality risk. However, little evidence is available on associations between PM2.5 and years of life lost (YLL). We aimed to estimate the YLL due to chronic obstructive pulmonary disease (COPD) mortality related to ambient PM2.5 exposure.Methods: A time-series study was conducted based on the data on air pollutants, meteorological conditions and 18,472 registered COPD deaths in Ningbo, China, 2011-2015. The effects of PM2.5 on YLL and daily death of COPD were estimated, after controlling long term trend, meteorological index and other confounders.Results: The impact of PM2.5 on YLL due to COPD lasted for 5 days (lag 0-4). Per 10 μg/m3 increase in PM2.5 was associated with 0.91 (95%CI: 0.16, 1.66) years increase in YLL. The excess YLL of COPD mortality were 8206 years, and 0.38 day per person in Ningbo from 2011 to 2015. The exposure-response curve of PM2.5 and YLL due to COPD showed a non-linear pattern, with relatively steep at low levels and flattened out at higher exposures.. Furthermore, the effects were significantly higher in the elderly than those in the younger.Conclusions: Our findings explored burden of PM2.5 on YLL due to COPD and highlight the importance and urgency of ambient PM2.5 pollution control and protection of the vulnerable populations. [ABSTRACT FROM AUTHOR]

To investigate the characterization of chemical compositions in size-segregated particles during severe haze pollution episodes in different regions of China, a campaign was conducted in Tianjin, Hangzhou and Chengdu. Size-segregated particles were collected with eight-stage Anderson cascade impactor in these cities in winter respectively. Ten major compositions of particles including (Na + , NH 4 + , K + , Mg 2 + , Ca 2 + , Cl − , NO 3 − , SO 4 2 − , OC and EC) were analyzed. A similar bimodal distribution of particles was found between northern and southern cities peaked at 0.7–2.1 and 9.0–10.0 μm. OC, EC, SO 4 2 − , NO 3 − , Cl − and NH 4 + were the major chemical compositions of fine-mode particles, whereas OC, EC, SO 4 2 − , NO 3 − and Ca 2 + were the major compositions of coarse-mode particles. In the three cities, Cl − , SO 4 2 − , NO 3 − , NH 4 + and K + of all compositions were unimodal distributions peaked at 0.7–2.1 μm. Different sources to particles in the three cities were inferred based on the size distribution characteristics of chemical compositions. For Tianjin, the influence of sea salt was greater to Hangzhou and Chengdu based on the concentrations and distributions of Na + and the Cl − . Fine-mode Cl − and SO 4 2 − were highest in Tianjin, meaning the greater contribution of coal burning to particles during severe pollution. For Hangzhou, the NO 3 − concentration was higher than Tianjin and Chengdu. Contribution of nitrate to PM was higher than that of sulfate. For Chengdu, carbonaceous species contributed mostly to fine particles. However, sulfate and nitrate contributed mostly to fine particles in Tianjin and Hangzhou. The contributions of EC and Ca 2 + to coarse-mode particles was much higher than that in other cities, implying the greater influence of soil particles, construction dust or falling dust to PM in Chengdu. In addition, there were greater emission source of NH 4 + in Chengdu. Northwest, west and southeast were the major transport pathways of air masses for Tianjin, Hangzhou and Chengdu. [ABSTRACT FROM AUTHOR]

Chemical composition, morphology, size and mixture of fine particles were measured in a heavy haze and the post-haze air in Beijing in January 2012. With the occurrence of haze, the concentrations of gaseous and particulate pollutants including organics, sulfate, nitrate, and ammonium grew gradually. The hourly averaged PM 2.5 concentration increased from 118 μg m − 3 to 402 μg m − 3 within 12 h. In contrast, it was less than 10 μg m − 3 in the post-haze air. Occupying approximately 46% in mass, organics were the major component of PM 1 in both the haze and post-haze air. Analysis of individual particles in the size range of 0.2–1.1 μm revealed that secondary-like particles and soot particles were always the majority, and most soot particles had a core-shell structure. The number ratio of secondary-like particles to soot particles in accumulation mode in the haze air was about 2:1, and that in the post-haze air was 8:1. These results indicate both secondary particle formation and primary emission contributed substantially to the haze. The mode size of the haze particles was about 0.7 μm, and the mode size of the post-haze particles was 0.4 μm, indicating the remarkable growth of particles in haze. However, the ratios of the core size to shell size of core-shell structure soot particles in the haze were similar to those in the post-haze air, suggesting a quick aging of soot particles in either the haze air or the post-haze air. [ABSTRACT FROM AUTHOR]

The concentrations of halogenated flame retardants (HFRs) in PM2.5 were monitored for one year at 10 urban sites in China during 2013-2014. This study investigated four classes of HFRs: nine polybrominated diphenyl ethers (PBDEs), six nonbromodiphenyl ether (BDE) brominated flame retardants, two dechlorane plus (DP) flame retardants, and three chlorinated organophosphate flame retardants (OPFRs). Extremely high concentrations of BDE-209 and DBDPE were observed in only one city (Guangzhou), which was a consequence of the intensive e-waste recycling and disposal operations in the Pearl River Delta. This result differed from the tris(monochloropropyl) phosphate (TCPP) and tris(2-chloroethyl) phosphate (TCEP) distributions, which showed high concentrations in most cities, suggesting wide usage and large emissions in China in recent years. The highest TCPP and TCEP concentrations were observed in the summer, indicating that emission from local sources was an important factor controlling the levels in the air. This was not the case for BDE-209 and DBDPE, for which higher concentrations were found in winter. When bound to particulate matter due to low vapor pressure, these compounds may be more persistent in air, and temperature-dependent gas-particle partitioning was a key factor. Moreover, regional pollution and long-range transport had a significant influence on the seasonal distributions of BDE-209 and DBDPE, especially in cities (Guangzhou and Shanghai) close to electrical/electronic waste recycling sites. Residents in urban areas were exposed to higher levels of chlorinated OPFRs. This raises considerable concern, and an appropriate risk assessment is required. [ABSTRACT FROM AUTHOR]

Though increasing evidence supports significant association between particulate matter (PM) air pollution and stroke, it remains unclear what characteristics, such as particle size and chemical constituents, are responsible for this association. A time-series model with quasi-Poisson function was applied to assess the association of PM pollution with different particle sizes and chemical constituents with mortalities from ischemic and hemorrhagic strokes in Guangzhou, China, we controlled for potential confounding factors in the model, such as temporal trends, day of the week, public holidays, meteorological factors and influenza epidemic. We found significant association between stroke mortality and various PM fractions, such as PM10, PM2.5 and PM1, with generally larger magnitudes for smaller particles. For the PM2.5 chemical constituents, we found that organic carbon (OC), elemental carbon (EC), sulfate, nitrate and ammonium were significantly associated with stroke mortality. The analysis for specific types of stroke suggested that it was hemorrhagic stroke, rather than ischemic stroke, that was significantly associated with PM pollution. Our study shows that various PM pollution fractions are associated with stroke mortality, and constituents primarily from combustion and secondary aerosols might be the harmful components of PM2.5 in Guangzhou, and this study suggests that PM pollution is more relevant to hemorrhagic stroke in the study area, however, more studies are warranted due to the underlying limitations of this study. [ABSTRACT FROM AUTHOR]

Limited studies have examined the associations between air pollutants [particles with diameters of 10 μm or less (PM 10 ), sulphur dioxide (SO 2 ), and nitrogen dioxide (NO 2 )] and fasting blood glucose (FBG). We collected data for 27,685 participants who were followed during 2006 and 2008. Generalized Estimating Equation models were used to examine the effects of air pollutants on FBG while controlling for potential confounders. We found that increased exposure to NO 2 , SO 2 and PM 10 was significantly associated with increased FBG levels in single pollutant models (p < 0.001). For exposure to 4 days' average of concentrations, a 100 μg/m 3 increase in SO 2 , NO 2, and PM 10 was associated with 0.17 mmol/L (95% CI: 0.15–0.19), 0.53 mmol/L (95% CI: 0.42–0.65), and 0.11 mmol/L (95% CI: 0.07–0.15) increase in FBG, respectively. In the multi-pollutant models, the effects of SO 2 were enhanced, while the effects of NO 2 and PM 10 were alleviated. The effects of air pollutants on FBG were stronger in female, elderly, and overweight people than in male, young and underweight people. In conclusion, the findings suggest that air pollution increases the levels of FBG. Vulnerable people should pay more attention on highly polluted days to prevent air pollution-related health issues. [ABSTRACT FROM AUTHOR]

Metal migration processes, by means of gas-transported particles, from an iron magnetite skarn deposit beneath Quaternary transported overburden, to surface was studied at the Kaxiutata iron deposit. This study area is located in the desert of the Inner Mongolia region in northern China. Ascending gas-transported particles were collected using passive adsorption methods; a total of 50 samples were obtained over the known mineralization (30 within the mining area and 20 from the exploration area), and 15 samples were collected over background areas for comparison. The morphology, categorization, and chemical composition of particles in these samples were determined by transmission electron microscopy (TEM). In the mining and exploration area, the particles related to the subsurface mineralization (ore-bearing particles) are primarily Fe-, Cu-, Zn-, Pb-, and Bi-bearing, and particles show significant common characteristics. Sulphur is generally absent, or its content is notably low. However, based on the geological description of primary mineralization, Cu, Zn, and Pb occur mainly as sulphides, implying that the minerals were subjected to in situ or transport-associated oxidation. Most particles are actually aggregates of various smaller particles of diverse origin. Evidence of oxidation and agglomeration of particles may reflect the high porosity and gas permeability of the sandy overburden, which provides an oxidizing environment for gas-transported particles. The distribution of ore-bearing particles is correlated with the subsurface mineralization. Iron-rich particles (> 30% Fe) and Cu-, Zn-, and Bi-bearing particles collected above the mining area were also collected in the exploration zone, and these types of particles are likely indicators of underlying iron mineralization. Samples collected from the background zone revealed no Cu-, Bi-, Mo-, and Pb-bearing particles. The migration mechanism of gas-transported particles in the desert area is summarized and discussed based on this and previous studies. [ABSTRACT FROM AUTHOR]

There is an increasing interest in understanding ambient bioaerosols due to their roles both in health and in climate. Here, we deployed an Ultraviolet Aerodynamic Particle Sizer to monitor viable (fluorescent) bioaerosol concentration levels at city centers (highly polluted) and their corresponding suburbs (near pristine) (total 40 locations) in 11 provinces featuring different climate zones in China between July 16 and 28, 2013. The concentration levels of viable bioaerosol particles (BioPM) of >0.5 µm were measured, and corresponding percentages of BioPM% (biological fraction of total PM) and BioPM% (biological fraction of PM) in particulate matter (PM) and BioPM, respectively, were determined. For some key cities, indoor viable bioaerosol levels were also obtained. In addition, bacterial structures of the air samples collected across these monitoring locations were studied using pyrosequencing. BioPM concentration levels ranged from 2.1 × 10 to 2.4 × 10/m for city centers [BioPM% = 6.4 % (±6.3 %)] and 0.5 × 10 to 4.7 × 10/m for suburbs [BioPM% = 10 % (±8.7 %)]. Distinctive bioaerosol size distribution patterns were observed for different climate zones, e.g., some had fluorescence peaks at 3 µm, while the majority had peaks at 1 µm. Ambient bacterial aerosol community structures were also found different for different geophysical locations. Results suggest that there was a poor overall relationship between PM and BioPM across 40 monitoring locations ( R = 0.081, two-tailed P value = 0.07435). Generally, city centers had higher PM concentrations than suburbs, but not BioPM and BioPM%. Indoor bioaerosol levels were found at least tenfold higher than those corresponding outdoors. Bacillus was observed to dominate the bacterial aerosol community in the air sample. [ABSTRACT FROM AUTHOR]

Recently, PM2.5 (particulate matter with diameter of 2.5 micron or less) has become a major health hazard from the polluted air in many cities in China. The regular gauze masks are used to prevent inhaling the PM2.5 fine particles; however, those masks are not able to filter out the PM2.5 because of the large porosity of the mask materials. Some well-prevented masks usually have poor breathability, which increases other health risks. In this study, a polysulfone based nanofiber for mask filtration material was synthesized by electrospinning. That nanofiber mask material was characterized by SEM, air permeability test, and PM2.5 trapping experiment. The results indicate that nanofiber mask material can efficiently filter out the PM2.5 particles and simultaneously preserve a good breathability. We attribute such improvement to the nanoscaled fibers, having the same porosity as that of regular gauze mask but with extremely reduced local interfiber space. [ABSTRACT FROM AUTHOR]

Marine aerosols over the East China Seas are heavily polluted by continental sources. During the Chinese Comprehensive Ocean Experiment in November 2012, size and mass spectra of individual atmospheric particles in the size range from 0.2 to 2.0 μm were measured on board by a single particle aerosol mass spectrometer (SPAMS). The average hourly particle number (PN) was around 4560 ± 3240 in the South Yellow Sea (SYS), 2900 ± 3970 in the North Yellow Sea (NYS), and 1700 ± 2220 in the Bohai Sea (BS). PN in NYS and BS varied greatly over 3 orders of magnitude, while that in SYS varied slightly. The size distributions were fitted with two log-normal modes. Accumulation mode dominated in NYS and BS, especially during episodic periods. Coarse mode particles played an important role in SYS. Particles were classified using an adaptive resonance theory based neural network algorithm (ART-2a). Six particle types were identified with secondary-containing, aged sea-salt, soot-like, biomass burning, fresh sea-salt, and lead-containing particles accounting for 32%, 21%, 18%, 16%, 4%, and 3% of total PN, respectively. Aerosols in BS were relatively enriched in particles from anthropogenic sources compared to SYS, probably due to emissions from more developed upwind regions and indicating stronger influence of continental outflow on marine environment. Variation of source types depended mainly on origins of transported air masses. This study examined rapid changes in PN, size distribution and source types of fine particles in marine atmospheres. It also demonstrated the effectiveness of high-time-resolution source apportionment by ART-2a. [ABSTRACT FROM AUTHOR]

Coal particles regularly flow into coalbed methane (CBM) wells with the formation water. Once they settle down in the bottom of CBM wells, the pump will get stuck and the reservoir will be buried. In conventional oilwells, sand cleanout is usually operated by circulating the cleaning fluid into the wellbore to bring sand particles to the surface. However, when applied in CBM wells, this traditional hydraulic particles hoisting technology would leak the working fluid into the formation, destroy the coalbed formation structure and jam the formed channel of gas because the bottomhole pressure (BHP) is low. In this paper, a continuous vacuum cleanout technology will be introduced, and it combines a novel jet pump with a concentric tubing string (CTS) to remove coal particles without placing hydrostatic loads on the reservoir. The novel jet pump has two nozzles and the CTS is assembled by the outer tubing and inner tubing. More specifically, a high pressure working fluid is pumped through the CTS annulus from the surface and then it is divided into two parts. One part of the fluid acts as the sand carrier fluid. The other part acts as the power fluid of the jet pump to create a localized drawdown which vacuums the carrier fluid together with coal particles into the jet pump, and then circulates coal particles to surface through the inner tubing. The detailed structure and the principle of the technology system are described, while a theoretical model is built to design and optimize the system which is based on the coal particles transport experiment data and the jet pump theory. The field applications have proved that the coal particles cleanout technology makes significant improvements in achieving high efficiency and preventing leakage in CBM wells, and more importantly, reduces the skin damage and improves the CBM production. [ABSTRACT FROM AUTHOR]

To fill the blank information for aerosol precipitation-scavenging research in north-west of China, the aerosol particle and raindrop size distributions were measured simultaneously during 1 September 2012 to 31 August 2013 in urban Lanzhou. The scavenging coefficients of thunderstorm and non-thunderstorm rain and snow events were studied and presented on the basis of nine selected precipitation cases including 3 snow and 6 rain events. The variation of scavenging coefficients of snowfall across the size distribution clearly exhibited a trough of lower values for particles of 1000 nm–2000 nm in diameter, while the particles smaller than 500 nm were scavenged efficiently by non-thunderstorm rain, and thunderstorm rain more effectively scavenged the particles in 500–1000 nm. The snow scavenging coefficients varied between 3.11 × 10 −7 s −1 and 1.18 × 10 −3 s −1 in the 10–10,000 nm size range. The scavenging coefficients of thunderstorm (non-thunderstorm) rain were between 8.25 × 10 −7 s −1 (7.48 × 10 −6 s −1 ) and 1.23 × 10 −3 s −1 (7.46 × 10 −4 s −1 ). Additionally, the number of particles in 10–50 nm was more sensitive to duration of snow, while snowfall intensity was more responsible for particle number concentrations in 50–100 nm and 100–1000 nm. The longer period of precipitation with lower raindrop velocity can more effectively scavenge the particles in the size range of 10–50 nm. [ABSTRACT FROM AUTHOR]

In January 2013, several serious haze pollution events happened in North China. Cimel sunphotometer measurements at an urban site of Beijing (Chinese Academy of Meteorological Sciences-CAMS) from 1 to 30 January 2013 were used to investigate the detailed variation of aerosol optical properties. It was found that Angstrom exponents were mostly larger than 0.80 when aerosol optical depth values are higher than 0.60 at the urban region of Beijing during January 2013. The aerosol optical depth (AOD) at the urban region of Beijing can remain steady at approximately 0.40 before haze happening and then increased sharply to more than 1.50 at 500 nm with the onset of haze, which suggests that the fine-mode AOD is a factor of 20 of the coarse-mode AOD during a serious haze pollution event. The single scattering albedo was approximately 0.90 ± 0.03 at 440, 675, 870 and 1,020 nm during the haze pollution period. The single scattering albedo at 440 nm as a function of the fine-mode fraction was relatively consistent, but it was highly variable at 675, 870 and 1,020 nm. Except on January 12 and 18, all the fine-mode particle volumes were larger than those of coarse particles, which suggests that fine particles from anthropogenic activities made up most of the haze. Aerosol type classification analysis showed that the dominant aerosol types can be classified as both 'mixed' and 'urban/industrial (U/I) and biomass burning (BB)' categories during the heavy haze period of Beijing in January of 2013. The mixed category occurrence was about 31 %, while the U/I and BB was about 69 %. [ABSTRACT FROM AUTHOR]

In this paper, an actual landslide process that occurred in Southern China is simulated by a continuum approach, the particle finite element method (PFEM). The PFEM attempts to solve the boundary-value problems in the framework of solid mechanics, satisfying the governing equations including momentum conservation, displacement-strain relation, constitutive relation as well as the frictional contact between the sliding mass and the slip surface. To warrant the convergence behaviour of solutions, the problem is formulated as a mathematical programming problem, while the particle finite element procedure is employed to tackle the issues of mesh distortion and free-surface evolution. The whole procedure of the landslide, from initiation, sliding to deposition, is successfully reproduced by the continuum approach. It is shown that the density of the mass has little influence on the sliding process in the current landslide, whereas both the geometry and the roughness of the slip surface play important roles. Comparative studies are also conducted where a satisfactory agreement is obtained. [ABSTRACT FROM AUTHOR]

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Coal-fired power plants are the important sources of anthropogenic atmospheric releases of various hazardous trace elements (HTE) because a large quantity of emissions can cause wide dispersion and possible long-distance transportation. To obtain the temporal trends and spatial variation characteristics of various HTE discharged from coal- fired power plants of China, a multiple-year comprehensive emission inventory of HTE including Hg, As, Se, Pb, Cd, Cr, Ni, and Sb has been established for the period 2000-2010. Thanks to the cobenefit removal effects of conventional particulate matter/sulfur dioxide/nitrogen oxides (PM/SO2/NOx) control devices, emissions of these 8 toxic elements have shown a gradual decline since the peak in 2006. The total emissions of Hg, As, Se, Pb, Cd, Cr, Ni, and Sb are substantial and are estimated at about 118.54, 335.45, 459.4, 705.45, 13.34, 505.03, 446.42, and 82.33 tons (t), respectively, in 2010. Shandong, Jiangsu, Shanxi, and Hebei always rank among the top ten provinces with the highest emissions. Further, future emissions for 2015 and 2020 are projected with scenario analysis. Advanced technologies and integrated management strategies to control HTE are in great need. [ABSTRACT FROM AUTHOR]

An opposed multi-burner (OMB) entrained-flow gasifier with coal water slurry feeding is developed by the East China University of Science and Technology. A 3D model is employed to numerically simulate the gas flow field, motion of char particles, and distributions of temperature and gaseous components in an OMB gasifier and in a conceptual two-stage gasifier modified from the OMB gasifier (TS-OMB gasifier). Results show that the TS-OMB gasifier produces higher concentration and productivity of the effective gases (CO+H2) with a slightly higher carbon conversion than the OMB gasifier. The reasons for the differences between these two types of gasifier are discussed by means of numerical simulation. This information is valuable for guiding the design of an advanced OMB gasifier. [ABSTRACT FROM AUTHOR]