Particulate matter emissions from light-duty gasoline vehicles under different ambient temperatures: Physical properties and chemical compositions.

Fine particulate matter (PM2.5) from vehicle exhaust is typically emitted at breathing height and thus imposes severe adverse effects on human health and air quality. However, there is currently limited knowledge on the characteristics of PM2.5 in exhaust, specifically its chemical components, at different ambient temperatures. Particulate emissions from typical light-duty gasoline vehicles (LDGVs) were investigated on a chassis dynamometer according to the Worldwide Harmonized Light-Duty Test Cycle at ambient temperatures of 38 °C, 28 °C, 15 °C, 5 °C and - 7 °C. The results showed a significant increase in particulate mass (PM) and particle number (PN) emissions with decreasing ambient temperature, particularly during cold starts below 5 °C. The particle size distributions exhibited distinct bimodal patterns, with accumulation-mode (AM) particles (60-125 nm) dominating the gasoline direct injection (GDI) distribution and nucleation-mode (NM) particles (8-12 nm) dominating the port fuel injection (PFI) distribution. AM particles were more temperature-sensitive than NM particles. Lower temperatures produced higher emissions of elements, carbonaceous components, and large-ring polycyclic aromatic hydrocarbons, while water-soluble ions showed an opposite trend. The total toxic equivalent, primarily influenced by benzo[a]pyrene, was significantly higher at -7 °C. The penalty distribution of LDGV PM and PN, defined by comparing the emissions at the various temperatures to those at regulated temperatures (23-30 °C), exhibited notable temporal heterogeneity (winter > autumn > spring > summer) and spatial heterogeneity (northern China > southern China). These findings are essential for establishing more stringent vehicle emission standards and improving emission models in cold environments.

Chiral Topological Superconductivity in Superconductor-Obstructed Atomic Insulator-Ferromagnetic Insulator Heterostructures.

Implementing topological superconductivity (TSC) and Majorana states (MSs) is one of the most significant and challenging tasks in both fundamental physics and topological quantum computations. In this work, taking the obstructed atomic insulator (OAI) Nb_{3}Br_{8}, s-wave superconductor (SC) NbSe_{2}, and ferromagnetic insulator (FMI) CrI_{3} as an example, we propose a new setup to realize the 2D chiral TSC and MSs in the SC/OAI/FMI heterostructure, which could avoid the subband problem effectively and has the advantage of huge Rashba spin-orbit coupling. As a result, the TSC phase can be stabilized in a wide region of chemical potential and Zeeman splitting, and four distinct TSC phases with superconducting Chern number N=-1,-2,-3, 3 can be achieved. Moreover, a 2D Bogoliubov-de Gennes Hamiltonian based on the triangular lattice of obstructed Wannier charge centers, combined with the s-wave superconductivity paring and Zeeman splitting, is constructed to understand the whole topological phase diagram analytically. These results expand the application of OAIs and pave a new way to realize the TSC and MSs with unique advantages.

High-spatiotemporal-resolution mapping of PM2.5 traffic source impacts integrating machine learning and source-specific multipollutant indicator.

Traffic sources are a major contributor to fine particulate matter (PM2.5) pollution, with their emissions and diffusion exhibiting complex spatiotemporal patterns. Receptor models have limitations in estimating high-resolution source contributions due to insufficient observation networks of PM2.5 compositions. This study developed a source apportionment method that integrates machine learning and emission-based integrated mobile source indicator (IMSI) to rapidly and accurately estimate PM2.5 traffic source impacts with high spatiotemporal resolution in the Beijing-Tianjin-Hebei region. Firstly, we utilized multisource data and developed various machine learning models to optimize the traffic-related pollutant concentration fields simulated by a chemical transport model. Results demonstrated that the Extreme Gradient Boosting (XGBoost) model exhibited excellent prediction accuracy of nitrogen oxide (NO2), carbon oxide (CO), and elemental carbon (EC), with the cross-validated R values increasing to 0.87-0.92 and error indices decreasing by 50-67%. Furthermore, we estimated and predicted daily mappings of PM2.5 traffic source impacts using the IMSI method based on optimized concentration fields, which improved spatially resolved source contributions to PM2.5. Our findings reveal that PM2.5 traffic source impacts display significant spatial heterogeneity, and these hotspots can be precisely identified during the pollution processes with sharp changes. The evaluation results indicated that there is a good correlation (R of 0.79) between PM2.5 traffic source impacts by IMSI method and traffic source contributions apportioned by a receptor model at Beijing site. Our study provides deeper insights of estimating the spatiotemporal distribution of PM2.5 source-specific impacts especially in regions without PM2.5 compositions, which can provide more complete and timely guidance to implement precise air pollution management strategies.

Response of organic aerosol in Beijing to emission reductions during the XXIV Olympic Winter Games.

Organic aerosol (OA) serves as a crucial component of fine particulate matter. However, the response of OA to changes in anthropogenic emissions remains unclear due to its complexity. The XXIV Olympic Winter Games (OWG) provided real atmospheric experimental conditions on studying the response of OA to substantial emission reductions in winter. Here, we explored the sources and variations of OA based on the observation of aerosol mass spectrometer (AMS) combined with positive matrix factorization (PMF) analysis in urban Beijing during the 2022 Olympic Winter Games. The influences of meteorological conditions on OA concentrations were corrected by CO and verified by deweathered model. The CO-normalized primary OA (POA) concentrations from traffic, cooking, coal and biomass burning during the OWG decreased by 39.8 %, 23.2 % and 65.0 %, respectively. Measures controlling coal and biomass burning were most effective in reducing POA during the OWG. For the CO-normalized concentration of secondary OA (SOA), aqueous-phase related oxygenated OA decreased by 51.8 % due to the lower relative humidity and emission reduction in precursors, while the less oxidized­oxygenated OA even slightly increased as the enhanced atmospheric oxidation processes may partially offset the efficacy of emission control. Therefore, more targeted reduction of organic precursors shall be enhanced to lower atmospheric oxidation capacity and mitigate SOA pollution.

Nonlinear effect of NOx concentration decrease on secondary aerosol formation in the Beijing-Tianjin-Hebei region: Evidence from smog chamber experiments and field observations.

During the COVID-19 lockdown in the Beijing-Tianjin-Hebei (BTH) region in China, large decrease in nitrogen oxides (NOx) emissions, especially in the transportation sector, could not avoid the occurrence of heavy PM2.5 pollution where nitrate dominated the PM2.5 mass increase. To experimentally reveal the effect of NOx control on the formation of PM2.5 secondary components (nitrate in particular), photochemical simulation experiments of mixed volatile organic compounds (VOCs) under various NOx concentrations with smog chamber were performed. The proportions of gaseous precursors in the control experiment were comparable to ambient conditions typically observed in the BTH region. Under relatively constant VOCs concentrations, when the initial NOx concentration was reduced to 40% of that in the control experiment (labelled as NOx,0), the particle mass concentration was not significantly reduced, but when the initial NOx concentration decreased to 20 % of NOx,0, the mass concentration of particles as well as nitrate and organics showed a sudden decrease. A "critical point" where the mass concentration of secondary aerosol started to decline as the initial NOx concentration decreased, located at 0.2-0.4 NOx,0 (or 0.18-0.44 NO2,0) in smog chamber experiments. The oxidation capacity and solar radiation intensity played key roles in the mass concentration and compositions of the formed particles. In field observations in the BTH region in the autumn and winter seasons, the "critical point" exist at 0.15-0.34 NO2,0, which coincided mostly with the laboratory simulation results. Our results suggest that a reduction of NOx emission by >60% could lead to significant reductions of secondary aerosol formation, which can be an effective way to further alleviate PM2.5 pollution in the BTH region.

Identification of quality markers for Cyanotis arachnoidea and analysis of its physiological mechanism based on chemical pattern recognition, network pharmacology, and experimental validation.

Cyanotis arachnoidea C. B. Clarke is a traditional Chinese medicinal herb that has a limited clinical use in the treatment of diabetes mellitus (DM) in minority areas of Guizhou in China. However, few prior reports are available on the quality control of Cyanotis arachnoidea, and its quality markers and hypoglycemic mechanism are still unclear. The purpose of this study is to explore the quality markers (Q-markers) of Cyanotis arachnoidea and predict its hypoglycemic mechanism. In this study, ultra-high-performance liquid chromatography (UHPLC) fingerprint combined with chemical pattern recognition were performed, and four differential components were screened out as quality markers, including 20-Hydroxyecdysone, 3-O-acetyl-20-hydroxyecdysone, Ajugasterone C, and 2-O-acetyl-20-hydroxyecdysone. Network pharmacology analysis revealed 107 therapeutic target genes of Cyanotis arachnoidea in DM treatment, and the key targets were Akt1, TNF, IL-6, MAPK3, and JUN. The hypoglycemic mode of action of Cyanotis arachnoidea may be mediated by tumor necrosis factor (TNF) signaling, cancer, insulin resistance, and JAK-STAT pathways. Molecular docking analysis disclosed that the foregoing quality markers effectively bound their key target genes. An in vitro experiment conducted on pancreatic islet ß-cells indicated that the forenamed active components of Cyanotis arachnoidea had hypoglycemic efficacy by promoting PI3K/Akt and inhibiting MAPK signaling. UHPLC also accurately quantified the quality markers. The identification and analysis of quality markers for Cyanotis arachnoidea is expected to provide references for the establishment of a quality control evaluation system and clarify the material basis and hypoglycemic mechanisms of this traditional Chinese medicine (TCM).

Complex temperature dependence of vehicular emissions: Evidence from a global meta-analysis.

The significant impact of low ambient temperature, which was less regulated, on vehicle exhaust emissions had garnered considerable attention. This study investigated the impact of ambient temperature on exhaust emissions based on the global meta-analysis. The estimated sizes (mean difference, MDt) of 11 exhaust pollutants were quantified with 1795 observations at low ambient temperatures (LATs, -18 °C to -7 °C) versus warm ambient temperatures (WATs, 20 °C-30 °C). The results indicated a strong and positive effect of LATs on vehicular emissions, with the average ratio of vehicular emission factors at LATs to those at WATs (EFLAT/EFWAT) ranging from 1.14 to 3.84. Oil-based subgroup analysis indicated a quite large MDt [NOx] of diesel engines (12.42-15.10 mg km-1·k-1). Particulate emissions were 0.22-1.41 mg km-1·k-1 enhanced during cold-start tests at LATs. The application of particulate filters on motor vehicles greatly reduced the impact of ambient temperature on tailpipe particulate emissions, at the expense of induced NOx emissions. During the Federal Test Procedure (FTP-75), exhaust emissions showed higher temperature dependence compared to the averaged levels (1.31-39.31 times). Locally weighted regression was used to determine exhaust temperature profiles, revealing that gasoline vehicles emitted more particulates at LATs, while diesel vehicles showed the opposite trend. Given the widespread use of motor vehicles worldwide, future motor vehicle emission standards should include tighter limits on exhaust emissions at LATs.

Efficacy and safety of methylphenidate and ginseng in cancer-related fatigue: a network meta-analysis of randomized controlled trials.

Background: Incidence of cancer-related fatigue (CRF), which can persist 5 to 10 years, is nearly 85% in cancer patients. It severely affects the quality of life and is strongly associated with poor prognosis. As clinical trial data on CRF treated with methylphenidate and ginseng, two potential medicines, has been accumulating, an updated meta-analysis was performed to evaluate and compare the efficacy and safety of the two medicines in CRF. Methods: Randomized controlled trials that investigated methylphenidate or ginseng in the treatment of CRF were identified through a literature search. The primary outcome was CRF relief. Standardized mean difference (SMD) was used to analyze the effect. Results: Eight studies on methylphenidate were included and the pooled SMD was 0.18 [95% confidence interval (95% CI): -0.00 to 0.35, P=0.05]. Five studies on ginseng were included and the SMD was 0.32 (95% CI: 0.17-0.46, P<0.0001). Results of network meta-analysis showed that the order was ginseng, methylphenidate, placebo from high efficacy to low and ginseng was significantly better than methylphenidate (SMD =0.23, 95% CI: 0.01-0.45). Incidences of insomnia and nausea caused by ginseng were significantly lower than those caused by methylphenidate (P<0.05). Conclusions: Both methylphenidate and ginseng can significantly ameliorate CRF. Ginseng may be superior to methylphenidate because ginseng may be more effective and might cause less adverse events. Head-to-head trials with fixed protocol are warranted to identify the optimal medical strategy.

[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.

Impacts of ezetimibe on risks of various types of cancers: a meta-analysis and systematic review.

BACKGROUND: Ezetimibe is a widely used medication to reduce the plasma cholesterol level, particularly low-density lipoprotein level. However, its impact on cancer remains controversial. Here, its impacts on risks of various types of cancers were meta-analyzed. METHODS: PubMed and Cochrane Library electronic databases were searched and randomized controlled trials with followed up for at least 24 weeks were selected and included. The experimental group was defined as those patients treated with ezetimibe alone or with other medications, and the control group was defined as those who received a placebo or the matched medication. The number of new cancer cases or cancer-related deaths was extracted. Statistical analysis was performed using Review Manager (version 5.3). RESULTS: Nine trials enrolling 35 222 patients were included in the analyses. Compared with the control group, ezetimibe increased the number of new intestine cancer patients [relative risk (RR), 1.30; 95% confidence interval (CI), 1.02-1.67; P = 0.03] and had a trend to increase the number of new breast cancer patients (RR, 1.39; 95% CI, 0.98-1.98; P = 0.07). There was no significant difference in new hepatobiliary cancer, prostate cancer, skin cancer or cancer of other sites. Ezetimibe did not significantly increase the risk of new cancer in total (RR, 1.03; 95% CI, 0.96-1.11; P = 0.38), cancer-related death (RR, 1.11; 95% CI, 0.98-1.26; P = 0.10) or cancer events (RR, 1.04; 95% CI, 0.97-1.12; P = 0.30). In terms of lipid-lowering effect, ezetimibe significantly reduced total cholesterol and low-density lipoprotein cholesterol, increased high-density lipoprotein cholesterol. CONCLUSION: Ezetimibe may increase the risk of intestine cancer and has a trend of increasing the risk of breast cancer. There is no evidence to support that it increases or decreases the risk of other types.

Identifying the fundamental drives behind the 10-year evolution of northern China's rural household energy and emission: Implications for 2030 and beyond.

Rural household energy, particularly solid fuels, in northern China is thought to be a major source of air pollution. However, there is no complete, systematic, and reliable dataset for northern China's rural areas owing to the diversity of energy types used and the difficulty in acquiring data, particularly for solid fuels. Here we assessed existing progress in estimating solid fuels and proposed a practical route for deriving the information on rural household energy consumption and structure in northern China spanning 2010-2020, with important findings. (i) In 2010, the total rural household energy consumption for northern China was 287.51 million tons standard coal equivalent (TCE), while for 2020, it decreased to 205.14 million TCE, showing a 29 % decrease and an annual down 3.3 % averagely. Among a number of underlying reasons, China's urbanization process, which made the rural population shrink year by year, was primarily responsible. (ii) The share of clean energy in northern rural areas began at 4.2 % in 2010 and grew to 15.6 % in 2020, displaying a sustained improvement in energy structure. Particularly in the second 5 years, the clean energy share of policy priority areas grew by 20.0 percentage points (from 15.0 % in 2010 to 35.0 % in 2020), which is more than 18 percentage points higher than the growth of non-priority areas (from 2.9 % in 2010 to 4.5 % in 2020). Clean air policy, particularly the "two replacements" (replace coal with gas and electricity), in priority areas played a core role in changing the energy structure. (iii) Although both air pollutants and CO2 are predicted to decrease in 2030, there is a large gap between expected 2030 emissions and hoped 2060 carbon neutrality in northern rural households. It is thus necessary to gradually boost the share of green electricity (non-fossil) and to reverse the trend of "biomass fuel curtailment" in rural residential sector. This calls for the improvement in biomass style (e.g., biomass pellets) and in stove efficiency (e.g., complete combustion).

Efficacy of ginseng oral administration and ginseng injections on cancer-related fatigue: A meta-analysis.

BACKGROUND: Up to 90% of patients who are under the active treatment suffer from cancer-related fatigue (CRF). CRF can persist about 10 years after diagnosis and/or treatment. Accumulating reports support that ginseng and ginseng injections are both potential drugs for the treatment of CRF but few studies put them together for analysis. METHODS: Two reviewers independently extracted data in 3 databases (PubMed, Cochrane Library and China National Knowledge Infrastructure) from their inception to May 24, 2021. The primary outcome was the effect of ginseng in alleviating CRF. The secondary outcome was ginseng in alleviating emotional or cognitive fatigue. Standardized mean difference (SMD) was employed. RESULTS: Twelve studies were included to evaluate efficacy of ginseng oral administration and ginseng injections on CRF. The pooled SMD was 0.40 (95% confidence Interval [95% CI] [0.29-0.51], P < .00001). Six studies were included to evaluate efficacy of ginseng oral administration on CRF and the SMD was 0.29 (95% CI [0.15-0.42], P < .0001). The order was 2000 mg/d, 3000 mg/d, 1000 mg/d and placebo from high efficacy to low. Ten studies were included to evaluate efficacy of ginseng injections on CRF and the SMD was 0.74 (95% CI [0.59-0.90], P < .00001). Emotional fatigue was reported in 4 studies, ginseng oral administration in 2 and ginseng injections in 2. The pooled SMD was 0.12 (95% CI [-0.04 to 0.29], P = .15). Cognitive fatigue was reported in 4 studies focusing on ginseng injections and the SMD was 0.72 (95% CI [0.48-0.96], P < .00001). CONCLUSION: Ginseng can improve CRF. Intravenous injection might be better than oral administration. Ginseng injections may alleviate cognitive fatigue. No evidence was found to support that ginseng could alleviate emotional fatigue.

Pharmacological and molecular analysis of the effects of Huangqi Jianzhong decoction on proliferation and apoptosis in GES-1 cells infected with H. pylori.

Background: Infection with Helicobacter pylori (H. pylori) can cause chronic gastritis and other digestive tract diseases, and represents a public health concern. Current anti-H. pylori treatment can result in antibiotic resistance and other adverse reactions. Huangqi Jianzhong decoction (HQJZD) is a prescription form of traditional Chinese medicine for chronic gastritis that increases probiotics and inhibits H. pylori. In this study, its anti-bacterial activity against H. pylori receives a preliminary evaluation, and a pharmacology analysis is performed to predict its underlying mechanisms. Methods: Human GES-1 cells are divided into a blank control group, a model group, a HQJZD low-dose (2.08 mg·mL-1), a high-dose group (4.16 mg·mL-1), and a positive control group (amoxicillin, 5 µg·mL-1). After culture, the CCK-8 method is used to detect cell viability; flow cytometry is used to detect cell apoptosis rate; and RT-qPCR is used to detect the expression of mRNA virulence factors, including HpPrtC, OPiA, IceA1, and BabA2. Network pharmacology analysis and molecular docking were performed to explore the mechanisms of HQJZD in treating H. pylori gastritis, based on its anti-H. pylori infection effect. Results: We noted lower cell survival rates in the model group, but higher apoptosis rates and mRNA expressions of HpPrtC, OPiA, IceA1, and BabA2 than in the control group (p < 0.05). Compared to the model group, the cell survival rate of each dosage group of Huangqi Jianzhong decoction and the positive control group increased significantly, while the apoptosis rate and the mRNA expressions of HpPrtC, OPiA, IceA1, and BabA2 were decreased significantly. The effect in each HQJZD group was dose-dependent (p < 0.05). Network pharmacological analysis involving 159 signaling pathways was used to screen 6 key active components of HQJZD and 102 potential target proteins for the treatment of H. pylori-related gastritis. The molecular docking results revealed that the 6 active compounds had a strong binding ability with the target proteins of ALB, IL-6, AKT1, IL-1B, and JUN. Conclusion: HQJZD effectively increases the proliferation rate of human GES-1 cells after infection, while reducing the level of apoptosis. The mechanism may be related to multiple components, multiple targets and pathways, which provides a scientific basis for further elucidating the mechanism of action, the pharmacodynamic material basis, and the clinical application of HQJZD against H. pylori infection.

Quality evaluation of the classical prescription, Danggui Jianzhong decoction, using ultra-high-performance liquid chromatography fingerprint, chemical pattern recognition, and network pharmacology.

Danggui Jianzhong decoction is a classical prescription that has been widely used for thousands of years. However, the quality of this formula is difficult to control owing to its complex chemical component system. In this study, a simple and efficient method comprising ultra-high-performance liquid chromatography fingerprint, chemical pattern recognition, and network pharmacology was established to evaluate the quality of this decoction. A total of 20 common peaks were obtained by fingerprint analysis and 19 chemicals were identified. The fingerprint similarity of 15 batch samples ranged from 0.963 to 0.991. Chemical pattern recognition analysis could clearly classify 15 batches of Danggui Jianzhong decoction into three groups. Further, seven chemical markers were screened out. A herbs-active components-targets-disease network was constructed and enrichment analyses were performed, which indicated that these 19 chemical components are the medicinal substances of Danggui Jianzhong decoction. Further, the mechanism employed by this formula to treat primary dysmenorrhea may be related to the regulation of inflammatory response. In conclusion, this combination approach enables accurate evaluation and prediction of the quality of Danggui Jianzhong decoction, and lays the foundation for studies on the material basis and exploration of the mechanism of Danggui Jianzhong decoction in the treatment of primary dysmenorrhea.

Analysis of the air pollution reduction and climate change mitigation effects of the Three-Year Action Plan for Blue Skies on the "2+26" Cities in China.

City clusters play an important role in air pollutant and greenhouse gas (GHG) emissions reduction in China, primarily due to their high fossil energy consumption levels. The "2 + 26" Cities, i.e., Beijing, Tianjin and 26 other perfectures in northern China, has experienced serious air pollution in recent years. We employ the Greenhouse Gas and Air Pollution Interactions and Synergies model adapted to the "2 + 26" Cities (GAINS-JJJ) to evaluate the impacts of structural adjustments in four major sectors, industry, energy, transport and land use, under the Three-Year Action Plan for Blue Skies (Three-Year Action Plan) on the emissions of both the major air pollutants and CO2 in the "2 + 26" Cities. The results indicate that the Three-Year Action Plan applied in the "2 + 26" Cities reduces the total emissions of primary fine particulate matter with an aerodynamic diameter of ≤ 2.5 µm (PM2.5), SO2, NOx, NH3 and CO2 by 17%, 25%, 21%, 3% and 1%, respectively, from 2017 to 2020. The emission reduction potentials vary widely across the 28 prefectures, which may be attributed to the differences in energy structure, industrial composition, and policy enforcement rate. Among the four sectors, adjustment of industrial structure attains the highest co-benefits of CO2 reduction and air pollution control due to its high CO2 reduction potential, while structural adjustments in energy and transport attain much lower co-benefits, despite their relatively high air pollutant emissions reductions, primarily resulting from an increase in the coal-electric load and associated carbon emissions caused by electric reform policies..

Effects of a start-stop system for gasoline direct injection vehicles on fuel consumption and particulate emissions in hot and cold environments.

Engine start-stop (S&S) technology has been substantially incorporated into modern vehicles to save fuel during idling in congested urban areas because fuel economy regulations have become more stringent. However, the potential for increasing particle emissions after engine restarts, especially in cold environments, is of great concern. To investigate the effects of S&S systems on fuel consumption and tailpipe emissions, a chassis dynamometer was employed to measure the fuel consumption, particulate matter (PM), solid particle number (PN), particle number size distribution and black carbon (BC) for a typical gasoline direct injection vehicle when the S&S was on (S&S-on) and when the S&S was off (S&S-off) according to the worldwide harmonized light-duty test cycle in both hot (28 °C) and cold (5 °C) environments. S&S operation resulted in 3.1-4.3% fuel-savings at 28 °C but had a tendency to increase particulate emissions, especially of BC (21.8-31.8%) and PM (19.2-32.8%). Although PN emissions with S&S-on over the entire cycle were slightly lower than those with S&S-off, more particles were emitted during the engine restart moments. In a cold environment, the fuel-savings advantage of the S&S system was weakened, and the negative impacts on the particle emissions during the restart moment worsened. The S&S system resulted in higher abundances of accumulation mode particles, especially under cold ambient conditions. The relationship between the PN reduction rates and idling segments was determining to be exponential. Our results indicate that the S&S system, which may increase particle emissions during restarts, does save fuel, and that a comprehensive evaluation of the system in cold environments is needed to determine the serviceability of new engine technologies and after-treatments.

Sulfate Formation Apportionment during Winter Haze Events in North China.

There is a large gap between the simulated and observed sulfate concentrations during winter haze events in North China. Although multiphase sulfate formation mechanisms have been proposed, they have not been evaluated using chemical transport models. In this study, the Weather Research and Forecasting model coupled with Chemistry (WRF-Chem) was used to apportion sulfate formation. It was found that Mn-catalyzed oxidation on aerosol surfaces was the dominant sulfate formation pathway, accounting for 92.3 ± 3.5% of the sulfate formation during haze events. Gas-phase oxidation contributed 3.1 ± 0.5% to the sulfate formation due to the low OH levels. The H2O2 oxidation in aerosol water accounted for 4.2 ± 3.6% of the sulfate formation, caused by the rapid consumption of H2O2. The contributions of O3, NO2 oxidation, and transition metal ion-catalyzed reactions in aerosol water could be negligible owing to the low aerosol water content, low pH, and high ionic strength. The contributions from in-cloud reactions were negligible due to the barrier provided by stable stratification during winter haze events.

[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.

Network meta-analysis and cost-effectiveness analysis of infliximab, cyclosporine and tacrolimus for ulcerative colitis.

BACKGROUND: Assess the efficiency and cost-effectiveness of infliximab, cyclosporine and tacrolimus for the treatment of ulcerative colitis (UC). METHODS: A literature search identified studies that investigated infliximab, cyclosporine or tacrolimus compared with placebo in UC patients. Short-term, long-term remission rates and response rates were employed to assess efficacy. Odds ratios with 95% confidence intervals were analyzed. A Markov model was constructed to simulate the progression in a cohort of patients with UC, with an over 10 years of time horizon, with a discount rate of 3%, and established threshold of €30,000/quality-adjusted life-year (QALY) or ¥82442/QALY. RESULTS: Results of network meta-analysis showed that the order was cyclosporine, tacrolimus, infliximab and placebo from high rate to low with regard to short-term clinical response. The comparison between infliximab versus cyclosporine achieved an incremental cost effectiveness ratio (ICER) of €184435/QALY and ¥531607/QALY, with a 0.34893 QALYs difference of efficacy, and an incremental cost of €64355 and ¥185494. Tacrolimus versus cyclosporine reached an ICER of €44236/QALY and ¥57494/QALY, with a difference of 0.40963 QALYs in efficacy, and a raising cost to €18120 and ¥23551. The probabilistic sensitivity analysis shows that cyclosporine would be cost-effective in the 75.8% of the simulations, tacrolimus in the 24.2%, and infliximab for the 0%. CONCLUSION: Infliximab, cyclosporine and tacrolimus as salvage therapies are efficacious. For long-term of clinical remission, the order of pharmacological agents was tacrolimus, infliximab and cyclosporine from high efficacy to low while no significant difference is seen. In cost-effectiveness analysis, the cyclosporine versus infliximab or tacrolimus is expected to be at best.

Non-negligible contributions to human health from increased household air pollution exposure during the COVID-19 lockdown in China.

BACKGROUND: Ambient and household air pollution are found to lead to premature deaths from all-cause or cause-specific death. The national lockdown measures in China during COVID-19 were found to lead to abrupt changes in ambient surface air quality, but indoor air quality changes were neglected. In this study, we aim to investigate the impacts of lockdown measures on both ambient and household air pollution as well as the short-term health effects of air pollution changes. METHODS: In this study, an up-to-date emission inventory from January to March 2020 in China was developed based on air quality observations in combination with emission-concentration response functions derived from chemical transport modeling. These emission inventories, together with the emissions data from 2017 to 2019, were fed into the state-of-the-art regional chemistry transport model to simulate the air quality in the North China Plain. A hypothetical scenario assuming no lockdown effects in 2020 was also performed to determine the effects of the lockdown on air quality in 2020. A difference-to-difference approach was adopted to isolate the effects on air quality due to meteorological conditions and long-term decreasing emission trends by comparing the PM2.5 changes during lockdown to those before lockdown in 2020 and in previous years (2017-2019). The short-term premature mortality changes from both ambient and household PM2.5 changes were quantified based on two recent epidemiological studies, with uncertainty of urban and rural population migration considerations. FINDINGS: The national lockdown measures during COVID-19 led to a reduction of 5.1 µg m-3 in ambient PM2.5 across the North China Plain (NCP) from January 25th to March 5th compared with the hypothetical simulation with no lockdown measures. However, a difference-to-difference method showed that the daily domain average PM2.5 in the NCP decreased by 9.7 µg m-3 between lockdown periods before lockdown in 2020, while it decreased by 7.9 µg m-3 during the same periods for the previous three-year average from 2017 to 2019, demonstrating that lockdown measures may only have caused a 1.8 µg m-3 decrease in the NCP. We then found that the integrated population-weighted PM2.5, including both ambient and indoor PM2.5 exposure, increased by 5.1 µg m-3 during the lockdown periods compared to the hypothetical scenario, leading to additional premature deaths of 609 (95% CI: 415-775) to 2,860 (95% CI: 1,436-4,273) in the short term, depending on the relative risk chosen from the epidemiological studies. INTERPRETATION: Our study indicates that lockdown measures in China led to abrupt reductions in ambient PM2.5 concentration but also led to significant increases in indoor PM2.5 exposure due to confined indoor activities and increased usages of household fuel for cooking and heating. We estimated that hundreds of premature deaths were added as a combination of decreased ambient PM2.5 and increased household PM2.5. Our findings suggest that the reduction in ambient PM2.5 was negated by increased exposure to household air pollution, resulting in an overall increase in integrated population weighted exposure. Although lockdown measures were instrumental in reducing the exposure to pollution concentration in cities, rural areas bore the brunt, mainly due to the use of dirty solid fuels, increased population density due to the large-scale migration of people from urban to rural areas during the Chinese New Year and long exposure time to HAP due to restrictions in outdoor movement.