[Emission Inventory of Building Material Industry in Henan Province Based on Multi-source Data Integration].

The building materials industry is a typical resource and energy-consuming industry, as well as one of the major sources of air pollution. As the world's largest producer and consumer of building material products, China thus far has insufficient research on the emissions of the building materials industry, and the data sources are short of multiplicity. In this study, the building materials industry in Henan Province was chosen,and the control measures inventory for pollution emergency response (CMIPER) was applied to the development of the emission inventory for the first time. Through the integration of multi-source data such as CMIPER, a pollution discharge permit, and environmental statistics, the activity data of the building materials industry was refined, and a more accurate emission inventory of the building materials industry in Henan Province was established. The results showed that the SO2, NOx, primary PM2.5, and PM10 emissions of the building materials industry in Henan Province in 2020 were 21788, 51427, 10107, and 14471 t, respectively. Cement and bricks and tiles were the two categories with the highest contribution of emissions from the building materials industry in Henan Province, accounting for more than 50% in total. TheNOx emission of the cement industry was a key issue, and the overall emission control level of the brick and tile industry was relatively unadvanced. The central and northern parts of Henan Province contributed the most emissions in the building materials industry, accounting for more than 60%. It is recommended to further implement ultra-low emission retrofit in the cement industry, and for other industries such as the bricks and tiles, the improvement of local emission standards is encouraged to persistently promote the emission control of the building materials industry.

[Characteristics and Source Apportionment of Vehicular VOCs Emissions in a Tunnel Study].

To explore the emission characteristics of volatile organic compounds (VOCs) from vehicular exhaust sources and evaporative sources with ethanol gasoline (E10) as the main fuel, VOCs sampling campaigns were carried out in the north third ring tunnel of Zhengzhou city for two consecutive weeks in December 2019. In addition, the characteristics of traffic flow and environmental information were also monitored in the tunnel. Firstly, 106 VOCs were quantified using gas chromatography/mass spectrometry (GC/MS), and then source apportionment of VOCs in the tunnel was carried out using a positive matrix factorization (PMF5.0)-chemical mass balance (CMB8.2) composite model. Finally, the ozone formation potential (OFP) and secondary organic aerosol formation potential (SOAFP) of vehicle exhaust sources and evaporative sources were analyzed using the maximum incremental reactivity (MIR) and fractional aerosol coefficient (FAC). The results showed that ρ(VOCs) in the tunnel was (2794.5±147.4) µg·m-3 during the experiment, among which halogenated hydrocarbons[(32.4±2.0)%] accounted for the highest proportion, followed by aromatic hydrocarbons[(27.5±0.6)%] and alkanes[(23.3±0.8)%]. Source apportionment of vehicular VOCs showed that exhaust emissions (62.5%)>evaporative emissions (37.5%), whereas the contribution of OFP was that exhaust emissions (71.9%)>evaporative emissions (28.1%), and the contribution of SOAFP was that exhaust emissions (75.8%)>evaporative emissions (24.2%). The dominant components of OFP in evaporative sources were m,p-diethylbenzene, isoprene, and trans-2-pentene, whereas m,p-diethylbenzene, m,p-xylene, and 1,2,3-trimethylbenzene were the dominant components of SOAFP. The major components of OFP in exhaust sources were m,p-xylene, 1,2,4-trimethylbenzene, and 1,3,5-trimethylbenzene, whereas m,p-xylene, m,p-diethylbenzene, and 1,3,5-trimethylbenzene were the dominant components of SOAFP. In regions where ethanol gasoline is used, special attention should be paid not only to the exhaust emissions control but also to strengthening the emissions reduction of VOCs from vehicle evaporative sources, especially the high active components such as aromatic hydrocarbons and alkenes.

[Emission Characteristics of Chemical Composition of Particulate Matter from Coal-fired Boilers].

Samples of particulate matter from coal-fired boilers of different tons were collected in Lanzhou city, and the water-soluble inorganic ions, carbonaceous species, water-soluble organic compounds (WSOC) and polycyclic aromatic hydrocarbons (PAHs) were analyzed. The results showed that SO42-, Cl-, and Ca2+ were the most important water-soluble ions in the coal-fired boiler samples, accounting for 35.13%, 23.16%, and 22.20% of the total mass of water-soluble ions, respectively. The pyrolysis composition spectra of the carbonaceous species were similar among the coal-fired boilers, and organic carbon fraction (OC1, OC2, OC3, and OC4),and elemental carbon fraction (EC1, EC2, and EC3) accounted for 1.04%, 8.26%, 20.09%, 6.78%, 51.08%, 7.09%, and 5.66% of the total carbon (TC), respectively. EC1 had the highest content and was the most important carbonaceous species. The average ratios of WSOC/TC and WSOC/OC were 0.09±0.07 and 0.23±0.12, respectively, and the difference among the boilers of different tons was large. Phenanthrene (Phe), pyrene (Pyr), and benzene(k)anthracene (BkF) were the three main components of the PAHs, accounting for 16.69%, 11.93%, and 10.66% of the total PAHs, respectively. The particulate water-soluble ions, organic/elemental carbon aerosol (OCEC) and WSOC emitted from different tons coal-fired boilers were not significantly linearly related to the tonnage of the steam boiler, and low molecular weight PAHs decreased with the increase of tonnage of the steam boiler.

Comparison of cortical bone trajectory versus pedicle screw techniques in lumbar fusion surgery: A meta-analysis.

BACKGROUND: Biomechanical studies have demonstrated that cortical bone trajectory (CBT) screw can provide a 30% increase in uniaxial yield pullout load than pedicle screw (PS). In addition, the insertion torque of CBT screw is 1.71 times higher than that of PS. A meta-analysis was conducted to evaluate clinical results between CBT screw technique and PS technique in lumbar fusion surgery. METHODS: An extensive search of literature was performed in PubMed, Embase, the Cochrane library. The following outcomes were extracted: visual analog scale (VAS), Oswestry disabilities index (ODI), Japanese Orthopaedic Association (JOA) score, complications, fusion rates, hospital stay, incision length, blood loss, and operation time. Data analysis was conducted with RevMan 5.3 and STATA 12.0. RESULTS: A total of 12 studies were included in the final analysis. The results indicated that CBT group with less blood loss [P < .01], less hospital stay [P < .01], and less incision length [P < .01] than PS group. There were no significant differences between 2 groups in other clinical parameters and outcomes. CONCLUSION: CBT technique provided similar clinical outcomes and fusion rates compared to PS technique in lumbar fusion surgery. However, CBT technique provided additional benefits of less blood loss, less hospital stay, and less incision length.

An Optimized Protocol of Azoxymethane-Dextran Sodium Sulfate Induced Colorectal Tumor Model in Mice.

Since azoxymethane (AOM)-dextran sodium sulfate (DSS) induced tumorigenesis was used to explore inflammation-associated carcinogenesis of sporadic colorectal cancer (CRC), different administration modes of AOM or DSS have been reported. In this article we optimized the protocol of the AOM-DSS modeling using C57BL/6 mice for study on sporadic CRC by intraperitoneal injecting AOM solution at a proper concentration with a 100 µl sterile syringe once, feeding with DSS solution for 7 days in a roll and change DSS solution every day. More than 100 C57BL/6 mice had been treated with the optimized protocol, and all mice were demonstrated suffering from colorectal tumors when sacrificed in 8 to 20 weeks after AOM injection. These tumors mainly occurred in distal segment of colorectum with an increase in tumor density, which was similar to CRC in human beings. Tumor per mouse was high, and variation of tumor number per mouse was low. The histology of tumor developed through the defined stage ranged from precursor lesions, adenomatous lesions, adenomas to adenocarcinomas. The modified protocol of AOM-DSS model is easy, cheap, with high tumor formation rate of colorectal tumors.

[Spatial Distribution Characteristics of NMHCs in Spring in Cangzhou City].

Simultaneous collections of non-methane hydrocarbons (NMHCs) were carried out at 15 sampling sites including urban, suburb and potential pollution areas in Cangzhou City in spring 2015. The results showed that NMHCs were generally higher in urban areas than those in suburb and rural areas; the highest concentration of NMHCs was observed at Cangzhou High-tech zone (urban area); the concentrations of NMHCs were significantly lower at rural sites than in most urban sites except Hejian site; vehicular emissions were the main sources of NMHCs in Cangzhou; Cangzhou chemical fertilizer plant and Cangzhou oil refinery had no significant influence on urban NMHCs during their shutdown period; Dagang Oilfield, with better oil and gas recovery systems, did not have a significant impact on urban NMHCs. In general, alkanes, alkenes and aromatics accounted for 65%, 16% and 19% of NMHCs in Cangzhou City, respectively; xylene (19%), ethylene (14%), toluene(11%), propylene (5%), isopentane (5%) and isopentene (5%) were the most dominant contributors to ozone formation potential; aerosol formation potential was mainly derived from toluene (28%), pinene (28%), xylene(16%), ethylbenzene (9%) and benzene (9%).

[Number Concentration and Size Distribution of Particles Emitted by Light-duty Gasoline Vehicles].

In this study, three GDI (gasoline direct injection) and one PFI (port fuel injection) light-duty gasoline vehicles were characterized for their particle emission (number concentration and size distributions). Two condensation particle counters (CPC) with different activation efficiencies (50% cut off diameter) were used. It was found that the number concentration of particles emitted by GDI gasoline vehicle was approximately one order of magnitude higher than that from PFI gasoline vehicle. High emission of particles occurred within the first 200 s of cold start. The number concentration of particles emitted from GDI vehicle was largely influenced by the vehicle working condition, while that of PFI vehicle was relatively stable despite of varying working conditions. The size distributions of particles emitted from GDI and PFI vehicles had both nucleation mode and accumulation mode. The peak diameter of nucleation mode particles was in the range of 20-27 nm, while that of accumulation mode particle was in the range of 80-95 nm. The number concentrations measured by the UCPC (50% cut off diameter of 2.5 nm) were 35% (GDI) and 50.4% (PFI), respectively, higher than those measured by the CPC (50% cut off diameter of 23 nm) used by the regulation.

[An investigation of the CH4 and N2O emission factors of light-duty gasoline vehicles].

In China, most of the studies of vehicular greenhouse gas (GHG) emissions have been focused on CO2 emissions. The investigation of non-CO2 GHGs, e.g. CH4 and N2O, are mainly carried out based on models developed in Europe and the US, and there are few vehicle emission tests for CH4 and N2O. In this study, 22 light-duty gasoline vehicles (LDGVs) were selected for tailpipe CH4 and N2O tests using chassis dynamometer, and their emission factors were obtained based on the NEDC driving cycle. The results showed that the CH4 emission factors of China I to China IV LDGVs were 0.048 g x km(-1), 0.048 g x km(-1), 0.038 g x km(-1) and 0.028 g x km(-1), respectively. For N2O, the emission factors of China I to China IV were 0.045 g x km(-1), 0.039 g x km(-1), 0.026 g x km(-1) and 0.021 g x km(-1), respectively. In the GHGs emissions (in terms of CO2 Eq.) per LDGV, the percentage of CH4 and N2O emissions decreased gradually with tightening of emission standards. The contribution of CH4 emissions was lower than 0.5% in the total emissions, and N2O share rate was between 3.03% and 6.35%. Therefore, tightening emission standards can effectively reduce the CH4 and N2O emissions, to mitigate the greenhouse effects caused by vehicle emissions.

[Analysis of surface composition of three-way catalysts of in-use vehicles].

The kinds and contents of surface elements in three-way catalysts of six light-duty in-use taxi cabs, which were mainly operated in Beijing and whose driving mileages were in the range of 34 x 10(4)-59 x 10(4) km, were determined by X-ray fluorescence spectrometry (XRF), and the effect of driving mileage on element content was investigated. Results showed that nearly 30 kinds of elements were present on the catalyst surface. The main elements of different samples were similar. The common elements of the pollutant on the front and rear catalysts were P, Ca, Zn and Mn etc., most of which are from engine oil and gasoline. S was only observed on the rear catalysts, indicating that S tends to deposit on the rear catalysts. After 34 x 10(4) km run, the P content increased very slowly and 40 x 10(4) km run S content reached a saturated value. While the contents of Ca, Zn and Mn still exhibit an increase tendency after 56 x 10(4) km. That means after 40 x 10(4) km driving mileage, the effects of P and S on the catalyst activity are minor, and the continuous deposit of Ca, Zn and Mn will lead to further decrease of the activity.

[Study on on-board measurements and modeling of vehicular emissions].

It's a basic work to study the characteristics of vehicular emissions and give emission factors for development of vehicular emission inventory and decision-making of the control strategies. On-board emission measurements of on-road vehicles are regarded as important complementary to emission laboratory dynamometer tests. On-board exhaust emission measurements were conducted on seven samples of gasoline cars in a typical road in Macao, using AVL DiGas 4000 light five-gas analyzer. It was found that there was an obvious reduction of gaseous pollutant emissions from cars equipped with electronic fuel injection and three-way catalytic converter system (referred to as EFI cars in the following), compared to old carburetor cars. The average volume concentrations of CO, HC and NO of carburetor cars were 227 x 10(-6), 1.57% and 1477 x 10(-6), respectively, while those of EFI cars were 33 x 10(-6), 0.21% and 131 x 10(-6), which were about 1/11 through 1/7 of the former. However, there were high emissions during the cold start of EFI cars. The arithmetical mean concentrations of CO and NO emissions of EFI cars were calculated and their absolute values were predominantly contributed by high concentrations with low frequency. Furthermore, the emission factors of gasoline cars were estimated by test data, and at the same time, MOBILES model was used to calculate average emission factors of gasoline cars in Macao in 2000. The ratios between the results calculated by model and estimated by experiment data were in the range of 59%-139%, which would narrow into 68%-132% if only annual average emission factors were compared. The results suggest that EFI + TWC systems equipped in vehicles have good effect on the emission reduction, but catalytic converters are not activated during the cold start. Technical improvement of EFI cars, which could reduce the occurrence of high emissions with low frequency during the operation, would decrease their average level on exhaust emissions a lot. Furthermore, it's reliable that the emission factors of gasoline cars in Macao calculated by modified MOBILES model.