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China implemented the China VI emission standard in 2020. The China VI emission standard has added requirements for the RDE (real-world driving emission) test. To evaluate vehicle CO2 emission for different vehicles, 10 conventional gasoline vehicles were tested under the RDE procedure using the PEMS (portable emission testing system) method. All vehicles tested meet the sixth emission regulation with a displacement of 1.4 L~2.0 L. Among the vehicles tested, the highest CO2 emission factor was 281 g/km and the lowest was 189 g/km, while the acceleration of RDE gets a wider distribution, varying from −2.5 m/s2 to 2.5 m/s2. The instantaneous mass emission rate could reach around 16 g/s. The amounts of total CO2 emission in the positive region and the negative region make up 82~89% and 11~18% of the overall CO2 emission during the entire RDE driving period, respectively. The same vehicle has a wide range of CO2 emission factors at different VSP (vehicle specific power) intervals. Different RDE test conditions can lead to large differences in CO2 emissions. [ABSTRACT FROM AUTHOR]

In the China VI regulations for light-duty vehicles, the (RDE) test is introduced as a supplementary test procedure. In the actual test process, the RDE results are more significantly influenced by driving behavior and vehicle type. To reduce the test cost, the NOx and PN prediction models are established based on the GA-BP method. The results showed that the coefficients of determination of the GA-BP model for NOx and PN predictions are all greater than 0.9 and are linearly highly correlated at the instantaneous emission level. At the overall emission level, the overall error of the GA-BP model is less than 7% for NOx prediction and less than 6% for PN prediction. The model has high accuracy for both instantaneous and overall emissions of light-duty vehicles. This provides practical engineering value for guiding the RDE test. [ABSTRACT FROM AUTHOR]

Diesel vehicle emissions generally deteriorate with vehicle mileage due to the wear and deterioration of vehicle parts. Most of the experimental studies on vehicle emission durability were carried out based on the standard operation cycles of engine or vehicle, few research investigated vehicle emission deterioration characteristics under real driving conditions. In this research, the real driving emission (RDE) test method was used to investigate and evaluate the emission deterioration characteristics of two China-V diesel vehicles equipped with DOC and SCR systems. The experimental results show the emissions of CO and NOx from the N2 and N3 diesel vehicles increase with the vehicle mileage, showing the tendency of emission deterioration. The calculated deterioration factors of N2 and N3 diesel vehicle CO and NOx emissions are greater than the recommended values in China standard HJ 438–2008, which means experimental study on the vehicle emissions durability is necessary. The vehicle emissions deterioration depends on real driving conditions and the vehicle usage over vehicle lifetime. Diesel vehicle emissions generally deteriorate with vehicle mileage due to the wear and deterioration of vehicle parts. The experimental results show the exhaust emissions from diesel vehicles increase with the vehicle mileage, showing the tendency of emission deterioration. [Display omitted] • The emissions of two China-Ⅴ diesel vehicles were investigated to evaluate the durability of emissions performance. • The work-based window method was used to process RDE data. • The emissions of CO and NOx from the N2 and N3 diesel vehicles increase with the vehicle mileage. • The calculated deterioration factors of N2 and N3 diesel vehicle emissions are greater than the recommended values. [ABSTRACT FROM AUTHOR]

The actual emission characteristics of CO, THC, NO x , and PM from 50 ships were tested by a portable emission measurement system. Statistical analysis of emission data was carried out based on model years and engine types. The results show that with the increase of the model year, the specific emissions of pollutants increase gradually, that is, the stage I ships (before 2000 years) emit more pollutants. For CO, the specific emissions for stage Ⅱ ships (between 2001 and 2010 years) increase by 3.99%–26.39% compared with those for stage Ⅲ ships (between 2011 and 2016 years), and for stage I and Ⅱ ships, the maximum specific emissions increase by 25.34%–36.95 under the same operating modes; The specific emissions of THC are similar to those of CO. The specific emissions of THC increase by 45.84%–52.97% for stage I and Ⅱ ships and the weighted emissions of stage Ⅱ ships are 9.37% higher than that of stage Ⅲ. For NO x , the specific emissions of stage I, Ⅱ and Ⅲ ships are gradually reduced by 1.64%–13.44% and 6.83%–23.19% respectively, and the specific emissions under cruise condition are increased by 16.15%–36.47% compared with maneuvering condition. Due to the limitation of fuel products and test methods, PM emission characteristics are slightly different from other pollutants for different stage ships, but weighted emissions considering errors are reduced by 22.49%–25.59%. For different engine types, the specific emissions of high speed engines are higher than those of medium speed engines, especially for CO and THC pollutants, which are 16.05%–36.61% and 6.52%–73.31% higher respectively; On the contrary, for NO x , the emissions for each stage ships are reduced by 8.21%–8.82% compared with those for other stages, and PM has no consistent trend. At the same time, compared with foreign experimental data (European, USA, Sweden, et al.), the emissions of domestic ships, traveling on major routes (Yangtze river basin and Shandong coastal area and so on) in China, are about 1.1–5.11 times than that of other countries. • The specific emissions of different pollutants were increasing with service years. • CO and HC have the same emission characteristics for different conditions in China. • NO x has opposite emission characteristics with CO under different operating modes. • China's actual emission value is 1.18–5.11 times higher than the foreign database. • Slow speed engines emit more emissions than the other two types of engines. [ABSTRACT FROM AUTHOR]

On-road driving emissions of six liquefied natural gas (LNG) and diesel semi-trailer towing vehicles (STTVs) which met China Emission Standard IV and V were tested using Portable Emission Measurement System (PEMS) in northern China. Emission characteristics of these vehicles under real driving conditions were analyzed and proved that on-road emissions of heavy-duty vehicles (HDVs) were underestimated in the past. There were large differences among LNG and diesel vehicles, which also existed between China V vehicles and China IV vehicles. Emission factors showed the highest level under real driving conditions, which probably be caused by frequent acceleration, deceleration, and start-stop. NOx emission factors ranged from 2.855 to 20.939 g/km based on distance-traveled and 6.719–90.557 g/kg based on fuel consumption during whole tests, which were much higher than previous researches on chassis dynamometer. It was inferred from tests that the fuel consumption rate of the test vehicles had a strong correlation with NOx emission, and the exhaust temperature also affected the efficiency of Selected Catalytic Reduction (SCR) after-treatment system, thus changing the NOx emission greatly. THC emission factors of LNG vehicles were 2.012–10.636 g/km, which were much higher than that of diesel vehicles (0.029–0.185 g/km). Unburned CH 4 may be an important reason for this phenomenon. Further on-road emission tests, especially CH 4 emission test should be carried out in subsequent research. In addition, the Particulate Number (PN) emission factors of diesel vehicles were at a very high level during whole tests, and Diesel Particulate Filter (DPF) should be installed to reduce PN emission. Fig. Portable Emissions Measurement System for test vehicles. a) PC; b) GPS; c) weather station; d) Exhaust flow meter; e) HORIBA OBS ONE for gaseous emissions; f) PPS-M for particulate emission; g) Batteries. Unlabelled Image [ABSTRACT FROM AUTHOR]

After-treatment devices of diesel engines effectively reduce exhaust emissions but deteriorate over time. Consequently, the China-VI emission regulation mandates a useful life of seven years or 700,000 km for after-treatment devices. Conventional engine bench aging methods, being costly and time-consuming, are inapplicable for long-term emission durability verification. This paper introduces an accelerated aging method based on the thermal accumulation and Arrhenius equation. Accelerated aging of four after-treatment devices of the same model at different temperatures and durations was carried out. Results revealed that barring the CDPF's PN filtration efficiency, the efficiencies of the DOC, SCR, and ASC catalysts declined with accelerated aging, especially under lower temperatures. Deterioration in conversion efficiencies of catalysts increased the NOx, CO, THC, and NH 3 emissions under cold- and warm-WHTC tests. Considering that the equivalent durability mileage of the after-treatment devices under 150 h 650 °C accelerated aging condition is approximately 870,000 km, while the CO, THC, PN, NOx, and NH 3 emission factors are 0.05 g/kWh, 0.21 g/kWh, 2.14 × 1010 #/kWh, 0.44 g/kWh, and 3.48 ppm, respectively, so the durability of the tested after-treatment devices could comply with the China-VI emission regulation. Although accelerated aging did not significantly affect PN emissions, it increased the balanced point temperature of CDPF and the proportion of sub-23 nm particles. If emission regulations further reduce the lower limit of PN measurement to 10 nm, it could negatively impact the emission durability of CDPF. In addition, comparing the 1000 h of conventional aging showed similar characteristics and results in NOx conversion efficiency and NOx emission, suggesting that the accelerated aging method is reliable. In conclusion, the accelerated aging method reduces the durability verification duration, providing a cost-effective regulatory tool for environmental protection authorities and guidance for manufacturers to optimize device performance and durability. • Accelerated aging method for after-treatment devices of diesel engines is developed • Catalyst performance deteriorates more seriously under low temperatures • NOx deterioration is most pronounced during accelerated aging • Accelerated aging is well-equated with conventional bench aging based on SCR [ABSTRACT FROM AUTHOR]

NOx emissions from diesel vehicles generally deteriorate with increased durability mileage owing to the wear and deterioration of engines and after-treatment systems. Three China-VI heavy-duty diesel vehicles (HDDVs) were selected for four-phase long-term real driving emission (RDE) tests using the portable emission measurement system (PEMS). After 200,000 km of on-road driving, the maximum NOx emission factor of the test vehicles (387.06 mg/kWh) was found to be significantly lower than the NOx limit of 690 mg/kWh. Under all driving conditions, the NOx conversion efficiency of selected catalytic reduction (SCR) decreased almost linearly as the durability mileage increased. Importantly, the deterioration rate of the NOx conversion efficiency in low-temperature intervals was discernibly higher than that in high-temperature intervals. The NOx conversion efficiency at 200 °C dropped by 16.67–19.82% with higher durability mileage; however, the highest values at 275–400 °C only decreased by 4.11%. Interestingly, the SCR catalyst at 250 °C showed strong NOx conversion efficiency and durability (maximum decline of 2.11%). Overall, the poor de-NOx performance of SCR catalysts at low temperatures significantly challenges the long-term effective control of NOx emissions from HDDVs. Thus, improving the NOx conversion efficiency and durability at low-temperature intervals is the top priority for SCR catalyst optimization; NOx emissions from HDDVs at low velocities and loads should also be monitored by environmental authorities. The linear fitting coefficient for the NOx emission factors of the four-phase RDE tests was 0.90–0.92, indicating that NOx emissions deteriorated linearly with an increase in mileage. Based on the linear fitting results, the NOx emission control of the test vehicles during 700,000 km of on-road driving was highly likely to be qualified. These results can be used by environmental authorities to supervise the NOx emission conformity of in-use HDDVs after validation using other types of vehicles. [Display omitted] • NOx deterioration of three HDDVs is assessed using long-term PEMS measurement. • NOx conversion efficiency of SCR deteriorates linearly with driving mileage. • Obvious deterioration in NOx conversion efficiency is noticed below 250 °C. [ABSTRACT FROM AUTHOR]

• A general accelerated aging method for aftertreatment devices of HDDEs was proposed and its equivalence was verified. • The NH 3 and N 2 O emission factors are not linear deterioration with the intensification of accelerated aging. • The NH 3 emission factors of test HDDE comply with China VI emission regulation in the whole useful life. • The N 2 O emission factors of test HDDE exceed EPA's limit in the whole useful life. A general accelerated aging method for aftertreatment devices of Heavy-duty Diesel Engine (HDDE) is proposed in this paper, and three sets of aftertreatment devices were aged according to this method. The error between the World Harmonized Transient Cycle (WHTC)-NOx emission factors of conventional aging and those of accelerated aging fitted by equivalent thermal accumulation is −4.12 to 3.13 %, which proves that the two methods have good equivalence. Meanwhile, the NH 3 and N 2 O emission characteristics and durability were tested by Fourier Transform Infra-Red Spectroscopy (FTIR) equipment. The results show that NH 3 and N 2 O emissions do not deteriorate linearly with the intensification of thermal aging like NOx. Except that the NH 3 emission of AT03 exceeds the limit of China VI emission regulation (the average and maximum NH 3 concentration in the WHTC test are 35.25 ppm and 350.30 ppm, separately), NH 3 emission of other aged devices meet the requirements. Combined with the equivalent durability mileage of 1130000 km of AT02, the test China VI HDDE can effectively control NH 3 emissions and has a large margin with the limit requirements. However, the deterioration rate of N 2 O emission gradually slows down with the intensification of accelerated aging. The accelerated aging tests also indicate that N 2 O generation is closely related to NH 3 in SCR, consistent with previous studies conclusions of low-temperature and high-temperature N 2 O generation mechanisms. Equally important is that the N 2 O emission emitted from test China VI HDDE is significantly higher than the emission limit of the Environmental Protection Agency (EPA). The N 2 O emission factors under the WHTC test are as high as 0.15 to 0.35 g/kWh, which should draw the attention of Chinese environmental regulatory authorities, who should start to formulate N 2 O emission limits and put forward complementary strategies to reduce N 2 O emissions from HDDEs. [ABSTRACT FROM AUTHOR]

Methanol is a feasible and promising alternative fuel for passenger cars, particularly in China. However, methanol-fueled vehicles struggle with stronger low-temperature operating instability and increased chance of misfire. In prior publications, the impacts of engine misfire on the regulated and unregulated emissions from methanol-fueled vehicles have been merely discussed. In this paper, regulated emissions, unburned methanol, carbonyl and VOC emissions from a China-5 (equivalent to Euro-5b+IUPR) certificated methanol-fueled car were measured over new European driving cycle (NEDC). By using a SAE J2901-compatible generator, two misfire rates (6% and 9%) were employed to mimic ordinary and severe engine malfunction statuses. Emission results were also put into comparison with the current Euro-5 and the upcoming Euro-6c OBD threshold limits, and used to estimate Carter MIR-based ozone forming potential. The results demonstrated that, both CO and THC emissions increased with misfire rate while NOx emission persistently decreased with intensified engine misfire. Even with a misfire rate up to 9%, all the regulated emissions were significantly lower than their thresholds regulated in Euro-5 and Euro-6c, which meant the current OBD requirements were too tolerant for methanol vehicles. It is proposed that, countries regarding methanol as a future option, shall promulgate methanol-specific emission standards in advance. Unburned methanol emission increased by at least 1.6 and 5.7 times when misfire rates of 6% and 9% were used. Both carbonyl and VOC emissions increased corresponding to higher misfire rates. Formaldehyde and toluene were found the key pollutants of carbonyls and VOCs. An increase in anticipated ozone forming potential (OFP) together with a decrease in specific reactivity (SR) was also noticed with the rising of misfire rate. Among all the pollutants, CO, toluene, xylene and formaldehyde were the chief species contributing to secondary ozone formation. [ABSTRACT FROM AUTHOR]

Particles emitted during braking account for a significant proportion of transport-related particles. The brake particles are still beyond supervision because no mandatory regulations were introduced to control the brake particle emissions. Many studies have been conducted about the brake particles, but the materials & methods used by these studies vary a lot, thus reducing the result comparability among these studies. This paper reviewed brake particle emissions from four aspects: experimental methods, emission characteristics, influencing factors, and future works. Six experimental methods corresponding to different application scenarios are summarized, and these methods require different modifications, skills, and expenses. Whatever the experimental methods, the sampling method needs careful design to reduce the particle transport loss and to ensure particle sampling efficiency. The reported brake particle emissions could exceed the sixth stage exhaust emission regulation (both EU and China), depending on the test procedures, friction materials, and data processing. The brake particle covers a broad size distribution (from a few nanometers to tens of microns), and more studies are needed about its physicochemical characteristics. The friction materials, system running-in, and friction temperature will significantly affect the brake particle emission characteristics, and these factors should be considered when designing the study procedure. The patterns about gaseous emission and non-brake particle emission need more attention, as these patterns might be helpful to understand the brake particle emission characteristics. Some filter&collection-based brake particle after-treatments have also been invented. Future studies should focus on the homogeneous test procedure, mechanism analysis, after-treatment, and non-airborne wear et al. • Different brake particle research methods were assessed. • Brake particle emission characteristics are summarized and compared. • Major factors affecting the brake particle emission are analyzed. • Future concerns for brake particle emission are proposed. [ABSTRACT FROM AUTHOR]

The light-duty moving average window (MAW) method, used for China 6 real driving emission (RDE) calculation, is quite complex with various boundaries. Previous research noticed that the MAW might underestimate the calculation results, while the reasons for this underestimation haven't been studied systematically. With 29 vehicles tested in 10 cities and different boundaries applied for calculation, this study quantitively analyzed the problem, causes, and impacts of the light-duty MAW method. The instantaneous utilization factor (IUF) is proposed for reason analysis. The current MAW method could weaken the supervision of real driving tests as more than 75% of the tests underestimated MAW results, with the largest underestimation being around 100%. The data exclusion could lead to biased MAW results. But without the exclusion, the MAW result couldn't always get an increase due to the IUF and window weighting factor variation. With the extended factors removed, the MAW result bias is significantly reduced. The MAW will lead to a lower IUF of the data at the start/end of the tests, and when the cold-start data is considered, this low utilization must be noticed. The effect from the data exclusion, extended factors, and the window characteristics are closely coupled and they should be taken into consideration simultaneously to consummate the calculation method. The current drift-check progress couldn't effectively monitor the portable emission measurement system (PEMS), especially during the tests. The MAW result might lead to unreasonable emission limits and the emission inventory. Relevant policy based on these results might be implausible. • The moving average window (MAW) method is evaluated systematically. • The MAW method could weaken the supervision of RDE tests. • Data exclusion, extended factors, and the window definition lead to biased results. • The current drift-check progress couldn't effectively monitor the PEMS. [ABSTRACT FROM AUTHOR]

• To get better fuel efficiency, vehicle application scenarios must be considered. • Particles emitted during GPF regeneration could occupy 69.92%–84.81% of the total particles. • GPF regeneration brings more thin particle exposure to the public. • CLTC doesn't close the gap between laboratory tests and real driving. Many studies have found that WLTC (The Worldwide harmonized Light vehicles Test Cycles) doesn't accord well to real driving in different regions and it's necessary to develop local test cycles. China announced its local test cycle in 2019: CLTC (China light-duty vehicle test cycle). To evaluate vehicle emission under different cycles, one conventional gasoline vehicle and its hybrid counterpart were tested on the chassis dynamometer following CLTC, WLTC, and RDE (Real Driving Emission). The fuel consumption between WLTC and RDE is at the same level. While for the conventional, CLTC fuel consumption is 8.41% higher than WLTC and for the hybrid, it's 20.23% lower than WLTC. To get better vehicle fuel efficiency, vehicle application scenarios must be considered. Frequent re-start and longer warm-up time of the hybrid leads to high CO emission than the conventional. High engine speed could result in instantaneous CO spikes and with these spikes, 25% of the total CO could be emitted in less than 10 s. For the conventional, NOx emitted during engine warm-up occupied 85.39%, 87.02%, 43.06%, 31.98%, and 55.43% of the total NOx respectively for CLTC, WLTC and three RDE tests. NOx emitted from the hybrid is less than 10% of the conventional due to lower engine load and less fuel enrichment. Hybrid particle emission is under good control with the equipment of the gasoline particle filter, but the regeneration might increase thin particle exposure to the public. For most pollutants, CLTC doesn't close the gap between laboratory tests and real driving. [ABSTRACT FROM AUTHOR]

Porous electrospun nanofibers, as new materials for solid-phase extraction, were synthesized by electrospinning and coupled with ultra high performance liquid chromatography and mass spectrometry to determine sulfonamide residues in environmental water. Aligned porous polystyrene electrospun nanofibers were fabricated under the mechanism of phase separation. The high-specific surface of these nanofibers (70 m(2)/g) could improve recoveries of the target sulfonamides 4-10 times compared with that of polystyrene nonporous material (3.8 m(2)/g). Under the optimized conditions, 13 sulfonamide residues showed an excellent linear relationship in the range of 0.125-12.5 ng/mL with a linear correlation coefficient (r(2)) greater than 0.99, and the detection limits of sulfonamides were as low as 0.80-5.0 ng/L. Compared to the commercial C18 and HLB columns, the homemade porous nanofibers columns had some merits including simple fabrication and extraction process, short process time and environmental friendliness. The optimized method was applied to eight water samples collected from different livestock farms (Xuzhou, China). The results showed that polystyrene porous nanofibers were promising to preconcentrate sulfonamides of different polarities in the waste water., (© 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Objective: To study the association between ADAM33 and keloid scars in the northeastern Chinese population., Methods: A total of 283 keloid scar patients and a control group of 290 healthy volunteers were recruited for this study. Six polymorphic loci (V4, T+1, T2, T1, S2 and Q-1 ) of ADAM33 were selected for genotyping. Genotypes were determined by using the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method., Results: We observed the frequency of the rs612709 A allele exhibited a significantly decreased frequency in cases than in controls(22 vs.39.6%, P<0.0001) We also found that the frequencies of H2 (GGAAGA) haplotypes was significantly higher in the case group than in the control group (P= 0.041). In contrast, the haplotype H8 (GGGAGG) was more common in the control group than in the case group (P=0.022)., Conclusions: Our data suggest that the ADAM33 polymorphisms may be associated with keloid scars in the northeastern Chinese population., (© 2014 S. Karger AG, Basel.)

Aim: to investigate the association between vitamin D receptor polymorphisms and circulating 1,25-Dihydroxyvitamin D (1,25(OH)2D) levels with keloid scar (KS) risk., Methods: A total of 261 patients with KS and 261 normal healthy individuals were enrolled. VDR gene polymorphisms were determined. Circulating 1,25(OH)2D levels were detected., Results: In this study, we investigated the role of four loci of VDR gene polymorphisms in determining the risk of KS in a Chinese cohort. We found that the TaqI C>T polymorphism was closely associated with the KS incidence. Carriers with CC genotype of TaqI had a higher chance of developing KS. Stratification analyses by sex showed that this trend exists only in female subjects but not in male subjects. Furthermore, the TaqI C>T polymorphism affects the circulating 25-Hydroxyvitamin D levels. The CC carriers had a significantly lower mean circulating 1,25(OH)2D level than TT carriers and CT carriers. KS subjects had significantly lower mean serum circulating 1,25(OH)2D level than controls. The receiver operating characteristic curve analysis revealed that the serum circulating 1,25(OH)2D level at the cut-off point of 16.1 ng/ml could discriminate KS subjects from controls., Conclusion: Collectively, these data provide evidence that the vitamin D/VDR pathway plays an important role in the development of KS. The TaqI gene polymorphisms of VDR and circulating 1,25(OH)2D levels may thus be used as potential markers for prediction of KS development., (Copyright © 2013 S. Karger AG, Basel.)