Study on Water Splitting of the 214-Type Perovskite Oxides LnSrCoO4 (Ln = La, Pr, Sm, Eu, and Ga).

We present a study on the electrocatalysis of 214-type perovskite oxides LnSrCoO4 (Ln = La, Pr, Sm, Eu, and Ga) with semiconducting-like behavior synthesized using the sol-gel method. Among these five catalysts, PrSrCoO4 exhibits the optimal electrochemical performance in both the oxygen evolution reaction and the hydrogen evolution reaction, mainly due to its larger electrical conductivity, mass activity, and turnover frequency. Importantly, the weak dependency of LSV curves in a KOH solution with different pH values, revealing the adsorbate evolving mechanism in PrSrCoO4, and the density functional theory (DFT) calculations indicate that PrSrCoO4 has a smaller Gibbs free energy and a higher density of states near the Fermi level, which accelerates the electrochemical water splitting. The mutual substitution of different rare-earth elements will change the unit-cell parameters, regulate the electronic states of catalytic active site Co ions, and further affect their catalytic performance. Furthermore, the magnetic results indicate strong spin-orbit coupling in the electroactive sites of Co ions in SmSrCoO4 and EuSrCoO4, whereas the magnetic moments of Co ions in the other three catalysts mainly arise from the spin itself. Our experimental results expand the electrochemical applications of 214-type perovskite oxides and provide a good platform for a deeper understanding of their catalytic mechanisms.

Volatile organic compounds (VOCs) emissions from internal floating-roof tank in oil depots in Beijing: Influencing factors and emission reduction strategies analysis.

The internal floating-roof tank is the main type of storage tank for refined oil products. The volatile organic compounds (VOCs) emission from the internal floating-roof tank plays a dominant role in the unorganized emission source of the oil depot. In this study, we selected six typical oil depots in Beijing to investigate VOC emission characteristics from the tank top vent hole using infrared imaging technology and flame ionization detector (FID). The results reveal that infrared thermal imager is efficient in quickly identifying the emission level of the tank discharge point. The ambient temperature and wind speed have a direct effect on sealing loss, the turnover can greatly influence the wall hanging loss, and the concentration of VOCs emitted from the tank top vent hole is negatively correlated with liquid height. Furthermore, the influence of accessories type of the internal floating-roof tank on the concentration of VOCs emission from the top vent hole is also studied when other parameters remain unchanged, and find the floating deck type and sealing mode have a significant influence on their VOCs emissions, of which the combination of pontoon type floating deck and secondary seal are effective in controlling the concentration of VOCs emitted from the tank top vent hole. Finally, based on our experimental results, several feasible emission reduction strategies are proposed in terms of source prevention and process control in order to achieve the fine management of the whole process. This paper provides important technical support and policy thoughts for VOCs emission control during oil storage.

[Characteristics and Source Apportionment of Atmospheric Ion Deposition During Winter and Spring in the Core Area of Beijing].

In recent years, the Ministry of Ecology and Environment and the Beijing Municipal Government have continuously strengthened the control indicators of dustfall. In order to grasp the characteristics and sources of ion deposition in dustfall, the filtration method and ion chromatography were used to determine the dustfall and ion deposition during winter and spring in the core area of Beijing, and the PMF model was carried out to analyze the sources of ion deposition. The results indicated:① the average values of ion deposition and its proportion in dustfall were 0.87 t·(km2·30 d)-1 and 14.2%, respectively. The dustfall and ion deposition on working days were 1.3 times and 0.7 times that on rest days, respectively. ② The coefficient of determination in the linear equations between ion deposition and precipitation, relative humidity, temperature, and average wind speed were 0.54, 0.16, 0.15, and 0.02, respectively. In addition, the coefficient of determination in the linear equations between ion deposition and PM2.5 concentration and dustfall were 0.26 and 0.17, respectively. Therefore, controlling the concentration of PM2.5 was crucial to treating ion deposition. ③ Anions and cations accounted for 61.6% and 38.4%, respectively, in the ion deposition, and SO42-, NO3-, and NH4+ accounted for 60.6% in total. The ratio of anion and cation charge deposition was 0.70, and the dustfall was alkaline. The ρ(NO3-)/ρ(SO42-) in the ion deposition was 0.66, which was higher than that of 15 years ago. ④ The contribution rates of secondary sources, fugitive dust sources, combustion sources, snow-melting agent sources, and other sources were 51.7%, 17.7%, 13.5%, 13.5%, and 3.6%, respectively.

Emission of VOCs from service stations in Beijing: Species characteristics and pollutants co-control based on SOA and O3.

Currently, air pollution is primarily characterized by PM2.5 and O3. Therefore, the co-control of PM2.5 and O3 has become an important task of atmosphere pollution prevention and control in China. However, few studies have been conducted on the emissions from vapor recovery and processes, which is an important source of VOCs. This paper analyzed the VOC emissions of three vapor process technologies in service stations and first proposed key pollutants for priority control based on the coordinated reactivity of O3 and SOA. The concentration of VOCs emitted from the vapor processor was 3.14-9.95 g m-3, compared to 631.2-717.8 g m-3 for uncontrolled vapor. Alkanes, alkenes, and halocarbons accounted for a high proportion of the vapor both before and after control. Among the emissions, i-pentane, n-butane, and i-butane were the most abundant species. Then, the species of OFP and SOAP were calculated through the maximum incremental reactivity (MIR) and fractional aerosol coefficient (FAC). The average source reactivity (SR) value of the VOC emissions from three service stations was 1.9 g g-1, while the OFP ranged from 8.2 to 13.9 g m-3 and SOAP ranged from 0.18 to 0.36 g m-3. By considering the coordinated chemical reactivity of O3 and SOA, a comprehensive control index (CCI) was proposed for the control of key pollutant species that have multiplier effects on environment. For adsorption, trans-2-butene and p-xylene were the key co-control pollutants, while toluene and trans-2-butene were the most important for membrane and condensation + membrane control. A 50% emission reduction of the top two key species that emission account for 4.3% averagely will reduce O3 by 18.4% and SOA by 17.9%.

[Chemical Composition of VOCs from Service Stations Vapor Processing Device and Associated Contributions to Secondary Pollution].

Vapor processing device is a device that can control the headspace pressure in the underground storage tanks and recover the vapor. By analyzing the chemical composition of volatile organic compounds (VOCs) at the inlet and outlet of the vapor processing device, the ozone formation potential (OFP) and secondary organic aerosol formation potential (SOAP) were estimated by maximum incremental reaction (MIR) and fractional aerosol coefficients (FAC), and the secondary pollution formation contribution of VOCs were quantitatively evaluated. The results showed that:① the ρ(total volatile organic compounds, TVOC) at the inlet and outlet of the vapor processing device were 436-706 g·m-3 and 4.98-10.04 g·m-3, respectively. Alkanes (72%±4%), oxygenated organics (14%±2%), and olefins (11%±5%) were the dominant components of VOCs emissions. There were little differences in VOCs emissions from the different vapor processing devices; the key species were i-pentane (approximately 25%), followed by n-butane, i-butane, and n-pentane. ② The ozone source reactivity (SR) of VOCs emissions from the outlet of the vapor processing device was 2.6-3.3 g·g-1, and the OFP was 3.5-25.6 g·m-3. Olefins contributed the most (43%-69%), followed by alkanes (20%-35%) and oxygenated organics (10%-22%). Butene, cis-2-butene, trans-2-butene, i-pentane, and propionaldehyde were the species that highly contributed to OFP. ③ Aromatics in VOCs emissions contributed the most to SOAP (80%-92%), and the main active species were toluene, 1, 2, 4-trimethylbenzene, 1, 3, 5-trimethylbenzene, and p-diethylbenzene. The research showed that different VOCs species emitted by the vapor processing device contributed obvious differences to the secondary atmospheric pollution, and butene species and aromatics such as toluene were the focus of VOCs emission control of vehicle gasoline and vapor processing device.

Electrochemical performance of CoSe2 with mixed phases decorated with N-doped rGO in potassium-ion batteries.

Potassium-ion batteries (PIBs) have received much attention as next-generation energy storage systems because of their abundance, low cost, and slightly lower standard redox potential than lithium-ion batteries (LIBs). Nevertheless, they still face great challenges in the design of the best electrode materials for applications. Herein, we have successfully synthesized nano-sized CoSe2 encapsulated by N-doped reduced graphene oxide (denoted as CoSe2@N-rGO) by a direct one-step hydrothermal method, including both orthorhombic and cubic CoSe2 phases. The CoSe2@N-rGO anodes exhibit a high reversible capacity of 599.3 mA h g-1 at 0.05 A g-1 in the initial cycle, and in particular, they also exhibit a cycling stability of 421 mA h g-1 after 100 cycles at 0.2 A g-1. Density functional theory (DFT) calculations show that CoSe2 with N-doped carbon can greatly accelerate electron transfer and enhance the rate performance. In addition, the intrinsic causes of the higher electrochemical performance of orthorhombic CoSe2 than that of cubic CoSe2 are also discussed.

Retrospective Comparison of Postoperative Fascia Iliaca Block and Multimodal Drug Injection on Early Function of the Knee in Femoral Fractures Using Retrograde Intramedullary Nailing.

Introduction: There is a common concern about the pain and rehabilitation of the knee after femoral retrograde intramedullary nailing. It is essential for early postoperative knee function required for physical self-maintenance in daily life. And a favorable rehabilitation of the knee usually promotes the quality of life. However, early rehabilitation is absent or insufficient for many patients in postoperative management. This retrospective study aims to evaluate the effect of early knee function improvement in comparison to postoperative fascia iliaca blocking (FIB) and multimodal drug injection (MDI). Patients and Methods. A retrospective analysis of 41 patients receiving femoral fracture treatment with retrograde intramedullary nailing, was performed during 2018-2020. 19 patients were treated with MDI as postoperative analgesia, and 22 patients were treated with FIB. Rehabilitation started on the first postoperative day and lasted for 3 months. Visual analog scale (VAS), the range of motion (ROM) of the knee, and single assessment numeric evaluation (SANE) were assessed. Results: There was no significant difference shown in any of the demographic, fracture types, and operative time. All patients performed regular and voluntary knee rehabilitation and weight-bearing at home following the instruction from the orthopedic staff. Pain in the FIB group at postoperative 1-day was milder (1.7 ± 1.1), compared with that in the MDI group (2.8 ± 1.3, p=0.038). There was a significant difference in VAS between two groups at postoperative 1-month (p=0.031), with a peak score in the FIB group (3.3 ± 0.9). At postoperative 3-month, both groups had pain relief with similar VAS (p=0.465). The ROM of the knee in both groups was continuously improved during the first three months. The SANE in the MDI group was significantly different compared with FIB at 1-month (p=0.026). However, scores of SANE were similar in both groups at 3 months (p=0.541). All patients were identified as fractures union at 9-month or 12-month follow-up. Conclusion: The knee pain was commonly experienced in this series of retrograde femoral nailings. Both MDI and FIB provided immediate and effective pain control after femoral fracture surgery. MDI was more beneficial to continuous pain control and knee rehabilitation in the early follow-up. The extent of pain relief and knee function improvement reached the same level at postoperative 3-month.

Characteristics of ambient ammonia and its effects on particulate ammonium in winter of urban Beijing, China.

To understand the characteristics of winter fine aerosol pollution in Beijing, we conducted continuous measurements of the atmospheric trace gas ammonia (NH3), PM2.5, and inorganic ions in PM2.5 at an urban site in Beijing from February 13 to March 17, 2015. The hourly average concentration of NH3 throughout the campaign was 15.4 ± 17.5 ppb. NH3 concentrations correlated well with NH4+ in PM2.5, indicating the dominant precursor role of NH3 on NH4+ formation. The diurnal profile indicated an increase in NH3 concentrations during the morning rush hours, which was likely due to vehicle emissions. The mean ammonium conversion ratio (NHR) was 0.26, with the highest value of 0.32 in the afternoon. Elevated NHR, nitrate oxidation ratio (NOR), and NH4+ coincided with the significant increase in O3 levels in the afternoon, indicating the large daytime formation of NH4NO3 via photochemical reactions. Moreover, higher NHR values occurred under higher relative humidity (RH >60%) and lower temperature (0-10 °C). NHR increased during the nighttime and correlated well with RH, indicating the dominant role of heterogeneous reactions on gas-particle partitioning. The sulfate oxidation ratio (SOR) and NOR showed positive correlations with RH, which suggests that the conversions of SO2 to SO42- and NO2 to NO3- were sensitive to changes in RH. The sustained increase in SO42- concentrations at RH >60% suggests that RH had a higher influence on SO42- formation than on NO3- formation. As the sole precursor of NH4+, NH3 significantly enhanced daytime NH4NO3 formation via homogeneous gas-phase reactions and also promoted sulfate formation via both homogeneous and heterogeneous reactions. Moreover, the back trajectory results inferred a high contribution of southwestern air masses to atmospheric NH3 and NH4+ aerosol variations in Beijing. The result suggests the need for controlling the vehicle emissions to reduce the high levels of NH3 and alleviate PM2.5 pollution in winter in Beijing.

[Localization of Soil Wind Erosion Dust Emission Factor in Beijing].

Soil wind erosion dust is one of the primary sources of fine particulate matter (PM2.5). Compared with the fugitive dust emission inventory of typical domestic provinces and cities, we found that the maximum among the contribution rates of soil wind erosion dust to the local total fugitive dust PM2.5 emission inventory was about 4 orders of magnitude higher than the minimum. This study provided a wind erosion equation and a determination method of parameter values. The remote sensing interpretation, China soil dataset, and meteorological data of each district in Beijing were used to achieve the spatial distribution of the vegetation coverage factor (V), soil erodibility index (I), and climatic factors (C) in the plain area of Beijing. This study also estimated the emission factor of soil wind erosion dust and its spatial distribution. The main conclusions are as follows: ① Taking 2017 and Beijing city as an example, it was found that the climatic factor (C) was underestimated to different extents by domestic scholars, and PM2.5 emission factors were overestimated or underestimated. ② V, I, and C showed apparent spatial differences and the average values of them were 0.63±0.09, 188±73, and 0.029±0.009, respectively. The maximum values of V, I, and C were 1.5, 2.1, and 4.5 times the minimum among all districts, respectively. ③ The PM2.5 emission factor of soil wind erosion dust in Beijing showed a high spatial distribution in the northwest and southeast. The average emission factor of the city was (0.0018±0.0008) t·(hm2·a)-1, which is 0.54 times the highest emission factor (Xicheng District) and 3.12 times the lowest (Pinggu District). The area proportions of standardized emission factors with higher intensity (0.6 to 0.8] and high intensity (0.8 to 1.0] was 0.72% and 0.04%, respectively.

[Emission Status and Standards of Volatile Organic Compounds from Chinese and Foreign Bulk Petroleum Terminals].

Chinese emission standard of air pollutants for bulk gasoline terminals (GB 20950-2007) stipulate standards for vapor emissions during gasoline storage and receiving in bulk gasoline terminals. However, the standards are not applicable to crude oil, aviation kerosene, naphtha, and other kinds of oil. We assess emission standards or directives for vapor processing equipment in terminals in the United States (US) and European Union (EU), and analyze the emission status of vapor processing equipment in three typical cities in China. We further propose revisions to GB 20950-2007. We made the following observations. ① US and EU standards include scope not only for gasoline, but also crude oil and other organic liquids. ② The emission limits of non-methane hydrocarbons defined in GB 20950-2007 are i) 0.5, 1.8, and 8.9 times those defined in Subpart XX, Subpart R, and Subpart Y in the US federal regulations, ii) 1.8 and 3.1 times those defined in Rule 462 and Rule 1142 in southern California law, and iii) 0.7 and 500 times those defined in EU and German directives, respectively. The vapor leakage limit for general areas of China is 0.5 times that defined in Subpart XX of the US standards, whereas the limits for some other specific areas of China, are 0.7 and 2.0 times those defined by Rule 462 and Rule 1142 in southern California law. ③ The numerical range of P5th-P95th of NMHC emissions from the inlet and outlet of vapor processing equipment in three typical cities of China were 115-811 g·m-3 and 0.1-20.0 g·m-3, respectively. The proportion of NMHC emission concentrations less than or equal to 10 g·m-3 at the outlet of vapor processing equipment was>85%. We suggest that the scope of application of GB 20950-2007 should be extended to crude oil, gasoline (including ethanol gasoline), aviation kerosene, and naphtha. The emission concentration limit of NMHC from vapor processing equipment should be tighten from 25 g·m-3 to 20 g·m-3, with a emission limit of 10 g·m-3 added for particular cases.

[Application of Test Method for Dust Suppression Efficiency of Wind Erosion Dust Suppressant].

Wind erosion dust suppressant is an effective measure for controlling wind erosion dust. This study used the Portable In-Situ Wind Erosion Laboratory (PI-SWERL) to evaluate the efficiency of domestic and foreign dust suppressants and to compare their control efficiency of PM2.5 in terms of spraying methods, dilution factors, and wind speed. The following results were noted.① According to the recommended dilution factor, G and Enviroseal (ES) dust suppressant solutions were treated and tested, respectively. The control efficiency of particulate matter with diameters less than 2.5 µm (PM2.5) corresponding to the droplet spraying method was better than the atomized spraying method; the G dust suppressant efficiency, at 99.5%, was better than ES and water, at 94.0% and 77.5%, respectively, at 17.2 m·s-1, which is equivalent to grade 8 wind. ② The G dust suppressant with dilution factors of 50, 100, 150, 200, and 400 times was tested. The dust suppression efficiency at a wind speed of 17.2 m·s-1 was 99.7%, 99.5%, 99.7%, 98.1%, and 95.9%, respectively. The best cost-effective dilution factor of G dust suppressant was 150 times. The efficiency of dust suppressants increased when the wind speed increased between 13.1 m·s-1 and 17.2 m·s-1. ③ The method of using PI-SWERL to test the efficiency of wind erosion dust suppressant can quantify the suppression efficiency of dust suppressant on PM2.5. It is recommended to conduct dust suppression during effective periods and to practice environmentally friendly methods of wind erosion dust suppression.

[Emission Characteristics of Wind-Eroded Dust from Concrete Batching Plants in Beijing].

Concrete batching plants are a typical source of fugitive dust in Beijing. In this study, two concrete batching plants in Beijing were used to test wind erosion of dust with a Portable In-suit Wind Erosion Laboratory (PI-SWERL) designed by the Desert Research Institute (DRI). Sand and aggregate storage piles and paved roads in concrete batching plants were tested to determine the emission characteristics of wind eroded dust. Combining the frequencies of disturbance of storage piles and paved road surface with local meteorological data, localized wind erosion dust emission factors of PM2.5 were established. Results demonstrate that:①There are small differences in daily average emission factors for PM2.5 between the aggregate warehouse entrance area, concrete loading area, social road import area, and concrete batching plant entrance area, with these being 0.45, 0.41, 0.31, and 0.30 kg·(hm2·d)-1, respectively. ②Daily average emission factors for PM2.5 of coarse stone, fine stone, coarse sand, and fine sand storage piles are 0.10, 0.12, 0.26, and 2.02 kg·(hm2·d)-1, respectively. Emission factors of fine sand storage piles are 20.5, 16.8, and 7.7 times greater than those of coarse stone, fine stone, and coarse sand, respectively, and spring emission factors are 6.4, 3.4, and 1.3 times greater than those of summer, autumn, and winter, respectively. ③Daily average emission factors for PM2.5 of storage piles and paved roads are 1.13 and 0.37 kg·(hm2·d)-1, respectively 3.9 and 1.3 times higher than the wind erosion factor from storage piles from AP-42 files (c11s12 concrete batching, 1995); the uncertainty range of the emission factor is 34%-92%. ④It is recommended to strengthen watering, sweeping, and cleaning of paved roads, and to ensure fully enclosed storage and use of spray water to reduce wind erosion of dust from storage piles, especially from fine sand piles.

[VOCs Emission Inventory of Service Stations in a Subcenter (Tongzhou District) of the City of Beijing].

As a subcenter of the city of Beijing, Tongzhou District is faced with enormous pressure from the rapid growth of VOCs emissions from service stations. In this study, a set of bottom-up VOCs inventory estimation methods for service stations in Tongzhou District is established. Using local VOCs emission factors of service stations in Beijing, combined with gasoline and diesel sales from every service station, a high resolution VOCs emission inventory of service stations in Tongzhou District from 2015 to 2022 was established. The results showed the following. ①An online monitoring system (OMS) based on unloading, refueling, and tank pressure vapor emission control measures can reduce the VOCs emission factor from 190 mg·L-1 to 115 mg·L-1, and when the percent onboard refueling vapor recovery system (ORVR) Penetration reaches to about 50%, the emission factors can be reduced to 131 mg·L-1 and 96 mg·L-1, respectively. The VOCs emission factor (13 mg·L-1) of diesel from the service station is 0.8% of the uncontrolled emission factor (1552 mg·L-1) of gasoline. ②The amount of VOCs emissions from service stations in Tongzhou District was 97.8 t·a-1 in 2015, and the emissions of gasoline and diesel were 96.2 t·a-1 and 1.6 t·a-1, respectively, accounting for 98.4% and 1.6%. The emissions were mainly concentrated in the area surrounding the new Beijing Municipal Government site. ③After implementation of the vapor recovery requirements of "Beijing's Clean Air Action Plan from 2013-2017," considering the increase in oil sales from 2017 to 2022, VOCs emissions of gasoline and diesel from service stations will decrease by 9% and 6%, respectively, compared to those of 2015 in Tongzhou District. Assuming that the OMS will also be installed at 28 (2000-5000) t·a-1 service stations by the end of 2022, VOCs emissions of service stations will be reduce by 13% compared to those of 2015. ④The measure of restricting the number of vehicles in operation by 50% can reduce VOCs emissions of service stations by (22±12)% every day during 2014 Asia-Pacific Economic Cooperation conference (APEC). ⑤It is suggested to strengthen vapor recovery supervision on service stations in the area surrounding the new Beijing Municipal Government site, and in summer and refueling idle such as in noon.

[Emission Characteristics of Wind Erosion Dust from Topsoil of Urban Roadside-Tree Pool].

This study characterized the wind erosion dust emissions from topsoil of urban roadside-tree pool. The study area is the Xicheng District of Beijing and uses GIS to obtain the spatial distribution of various road mileages. A full bore investigation method was carried out to survey tree pool in the Zhanlanlu Subdistrict to obtain the activity level of tree pool in the Xicheng district. The portable in situ wind erosion laboratory (PI-SWERL) was used to determine the emission factors of PM2.5 from the wind erosion dust from tree pool and to estimate the PM2.5 emission inventory of tree pool in the Xicheng District in 2016. The results showed that:①The annual emission factors per unit area of PM2.5 from tree pool of freeways' frontage roads, major roads, minor roads, and alleys are 47.9, 7.9, 14.9, and 29.9 g·(m2·a)-1, respectively. The reduction rate of PM2.5 emission factors from tree pool by precipitation was about 30.3% in 2016. ②The annual emission factors per unit mileage of PM2.5 from the tree pool of freeways' frontage roads, major roads, minor roads, branch roads, and alleys are 2.57, 2.33, 4.04, 7.31, and 5.44 kg·(km·a)-1, respectively, and the factors for branch roads are 1.3, 1.8, 2.8, and 3.1 times as much as those for alleys, minor roads, freeways' frontage roads, and major roads, respectively. Taking the emission factor for minor roads as an example, the winter emission factor is 1.3, 7.3, and 8.7 times greater than that in the spring, summer, and autumn, respectively. ③PM2.5 emissions from the tree pool in the Xicheng District of Beijing are 1.60 t·a-1, and the uncertainty range of the emission inventory is -143%~184%. The emissions in winter are 0.68 t·a-1, which are 1.1, 1.42, and 5.1 times greater than that in the spring, summer, and fall, respectively. The emission values for freeways' frontage roads, major roads, minor roads, collectors, and alleys account for 5.6%, 8.7%, 23.2%, 4.1%, and 58.4% of the total emissions, respectively. It is recommended that the urban roadside-tree pool be covered to reduce wind erosion dust emissions with materials that do not affect the growth of trees as soon as possible.

[Fugitive Dust Emission Characteristics from Building Construction Sites of Beijing].

Particulate matter (PM) is the primary air pollutant in Beijing, and its emission control is an important direction of air pollution prevention and control. Construction dust plays a significant role in the source of airborne particulate matter in Beijing. Due to population growth and economic development, the demand for residential and office space has been increasing which results in a high construction area in Beijing and dust pollution caused by construction activities. However, there are few studies focusing on fugitive dust emissions from construction sites and their contribution to air pollution in Beijing. Under this background, this paper established an estimation model of dust emission from construction sites, and used the localized emission factor to calculate the dust emission from 2000 to 2015 in Beijing, identified the emission characteristics and laws of construction dust emission and quantified the uncertainty range of the emissions. The WRF/CMAQ model system was used to simulate the contribution of dust pollution to quantify its influence on air quality. The results showed that the dust emission from construction sites in Beijing has been increasing, but the construction area is falling in recent years. However, the emission of PM is still high and needs to be paid enough attention. In the spatial distribution, the dust emissions in summer and autumn are larger than those in other seasons. As for spatial distribution, the construction dust is mainly concentrated in the urban function extension area and suburban area, which is related to the extension of population activities and the gradual development of urbanization. The contribution of construction dust to PM10 and PM2.5 concentration in the ambient air can reach 31.3 µg·m-3 and 9.6 µg·m-3, respectively. Through scenarios analysis, for further reduction of the emission from construction sites in 2030, more stricter standard for green construction and powerful supervision are needed.

[Characteristic of Particulate Emissions from Concrete Batching in Beijing].

With the economic development and population growth in Beijing, there is a strong need for construction and housing, which leads to the increase of the construction areas. Meanwhile, as a local provided material, the production of concrete has been raised. In the process of concrete production by concrete batching, there are numerous particulates emitted, which have large effect on the atmospheric environment, however, systematic study about the tempo-spatial characteristics of pollutant emission from concrete batching is still rare. In this study, we estimated the emission of particulates from concrete batching from 1991 to 2012 using emission factor method, analyzed the tempo-spatial characteristics of pollutant emission, established the uncertainty range by adopting Monte-Carlo method, and predicted the future emission in 2020 based on the relative environmental and economical policies. The results showed that: (1) the emissions of particulates from concrete batching showed a trend of "first increase and then decrease", reaching the maximum in 2005, and then decreased due to stricter emission standard and enhanced environmental management. (2) according to spatial distribution, the emission of particulates from concrete batch mainly concentrated in the urban area with more human activities, and the area between the fifth ring and the sixth ring contributed the most. (3) through scenarios analysis, for further reducing the emission from concrete batching in 2020, more stricter standard for green production as well as powerful supervision is needed.

[Study and Application of Test Method for VOCs Emission Factor of Refueling in Service Station].

VOCs emission of service station is one of the main sources of VOCs in Beijing. Uncontrolled emission factor (UEF) of refueling in China, US EPA, EEA respectively is 2.16, 1.31 and 1.00 times of CARB UEF (1008 mg·L-1). China's gasoline standards have changed in the last 20 years, and there is an urgent need to carry out the localization of gasoline refueling VOCs emission factor research. This paper compared test methods for refueling emission factors of European Union (EU) and California Air Resources Board (CARB) and found that the EU method was simpler and easier to operate than the CARB method, so we processed refueling VOCs emission factors test device in reference to EU test methods and chose a set of United States Stage Ⅱ vapor recovery system in Beijing service stations to carry out studies on VOCs emission factors. The results showed that: 1 For the fuel test tank, refueling vapor recovery efficiencies were 0.93 and 0.83 times of air to liquid volume ratio (A/L) of Stage Ⅱ respectively in winter and summer. Refueling emission factor in summer was greater than that in winter, and its recovery efficiency was lower than that in winter. 2 For the social vehicles, winter and summer refueling UEF respectively was (525±42) mg·L-1 and (963±174) mg·L-1, at the same time was 0.52 and 0.95 times of CARB refueling UEF (1008 mg·L-1) in A/L=0.The average value of emission factors respectively was (55±30) mg·L-1 and (112±108) mg·L-1 in A/L 1.05-1.07 in winter and summer. 3Refueling UEF without vapor recovery of social vehicles was chosen as the localized summer and winter refueling UEF in Beijing, we could calculate the emission factor of vapor recovery in different A/L combining with the linear equation of the fuel test tank.

[Anterolateral thigh fasciocutaneous flap for repair of open Achilles tendon defect].

OBJECTIVE: To explore the effectiveness of anterolateral thigh fasciocutaneous flap for repair of skin and soft tissue defect and simultaneous Achilles tendon reconstruction with modified methods of ilio-tibial bundle suture. METHODS: Between October 2009 and June 2011, 10 cases of Achilles tendon and soft tissue defects were treated. There were 7 males and 3 females, aged from 5 to 60 years (median, 40 years). Injury was caused by spoke in 5 cases, by heavy pound in 3 cases, and by traffic accident in 2 cases. The time between injury and admission was 2-24 hours (mean, 8 hours). The size of wound ranged from 11 cm x 7 cm to 18 cm x 10 cm; the length of Achilles tendon defect was 4-10 cm (mean, 7 cm). Three cases complicated by calcaneal tuberosity defect. After admission, emergency debridement and vacuum sealing drainage were performed for 5-7 days, anterolateral thigh fasciocutaneous flap transplantation of 11 cm x 7 cm to 20 cm x 12 cm was used to repair skin and soft tissue defects, and improved method of ilio-tibial bundle suture was used to reconstruct Achilles tendon. The flap donor site was closed directly or repaired with skin grafting to repair. RESULTS: All flaps and the graft skin at donor site survived, healing of wounds by first intention was obtained. All patients were followed up 6-18 months (mean, 10 months). The flap was soft and flexible; the flap had slight encumbrance in 3 cases, and the others had good appearance. At last follow-up, two-point discrimination was 2-4 cm (mean, 3 cm). The patients were able to walk normally. The range of motion (ROM) of affected side was (24.40 +/- 2.17) degrees extension and (44.00 +/- 1.94) degrees flexion, showing no significant difference when compared with ROM of normal side [(25.90 +/- 2.33) degrees and (45.60 +/- 1.84)degrees] (t = 1.591, P = 0.129; t = 1.735, P = 0.100). According to Arner-Lindhoim assessment method for ankle joint function, all the patients obtained excellent results. CONCLUSION: A combination of anterolateral thigh fasciocutaneous flap for repair of skin and soft tissue defects and simultaneous Achilles tendon reconstruction with modified methods of ilio-tibial bundle suture is beneficial to function recovery of the ankle joint because early function exercises can be done.

[Mass size distributions and existing forms of sulfate and nitrate and atmospheric environment in Beijing].

In order to understand the formations and the concentrations of the secondary sulfate and nitrate of PM10 in Beijing. From May 2008 to April 2009, MOUDI has been used to collect the PM10 samples in Beijing atmospheric environment and the ion chromatography has been used to analyze the inorganic water-soluble components of the PM10 samples. The results showed that the mass size distributions of soluble sulfate and nitrate of PM10 in Beijing were single-mode distribution and the peak rang was from 0.32 microm to 0.56 microm, and the primary formation ways was the chemical reaction in the gas phase. The results of partial correlation analysis indicated that the primary formations of sulfate and nitrate of PM10 in Beijing was (NH4)2SO4, NH4NO3, NaNO3, KNO3 and Ca(NO3)2. The mass concentration of secondary (NH4)2SO4 and NH4NO3 were (17.0 +/- 8.2) microg/m3 and (8.8 +/- 3.3) microg/m3 respectively, which accounted for (14.7 +/- 3.6)% and (7.6 +/- 2.2)% of PM10 respectively. The sum of them accounted for (22.3 +/- 4.3)% of PM10.

[Influence of traffic restriction on road and construction fugitive dust].

By monitoring the road and construction dust fall continuously during the "Good Luck Beijing" sport events, the reduction of road and construction dust fall caused by traffic restriction was studied. The contribution rate of road and construction dust to particulate matter of Beijing atmosphere environment, and the emission ratio of it to total local PM10 emission were analyzed. The results show that the traffic restriction reduces road and construction dust fall significantly. The dust fall average value of ring roads was 0.27 g x (m2 x d)(-1) in the "traffic restriction" period, and the values were 0.81 and 0.59 g x (m2 x d)(-1) 1 month and 7 days before. The dust fall average value of major arterial and minor arterial was 0.21 g x (m2 x d)(-1) in the "traffic restriction" period, and the values were 0.54 and 0.58 g x (m2 x d)(-1) 1 month and 7 days before. The roads emission reduced 60%-70% compared with before traffic restriction. The dust fall average values of civil architecture and utility architecture were 0.61 and 1.06 g x (m2 x d)(-1) in the "traffic restriction" period, and the values were 1.15 and 1.55 g x (m2 x d)(-1) 20 days before. The construction dust reduced 30%-47% compared with 20 days before traffic restriction. Road and construction dust emission are the main source of atmosphere particulate matter in Beijing, and its contribution to ambient PM10 concentration is 21%-36%. PM10 emitted from roads and constructions account for 42%-72% and 30%-51% of local emission while the local PM10 account for 50% and 70% of the total emission.