Carbon Monoxide Concentrations Research Articles

A Comparative Study of Hydrothermally Leached Al3TM and Al3TM-Rh (TM=Zr, V, Ce) Intermetallic Compounds for Catalytic Oxidation of Carbon Monoxide.

Rise of the mute assassin "carbon monoxide (CO)" levels impact all aerobic life. The elevated rates of CO concentration endure climatic and geographical characteristics that exacerbate air pollution. Herein, a simple approach for hydrothermal leaching (HyTL) of Al3TM-Rh0.5 (Target material (TM)=Zr, V, Ce) and Al3TM (TM=Zr, V, Ce) intermetallic compounds produces leached products of ZrO2, VO2, and CeO2 with Rhodium (Rh) as an active component. The characterization result reveals the HyTL process and the presence of the active Rh element that elevated the performance of HyTL-Al3Zr-Rh0.5 towards CO conversion compared to other samples. Further, the cubic ZrO2 phase selectively forms after HyTL at 130 °C even though the formation of the cubic ZrO2 phase takes place at a high temperature. Moreover, the presence of Rh promotes higher catalytic activity in all the cases with low temperatures. The advancement in the present study towards the catalytic oxidation of CO over the hydrothermally leached ZrO2-Rh nanocatalyst guarantees the perspective of the aggregation-activation process.

Differential effects of heat-not-burn, electronic cigarettes and conventional cigarettes on endothelial glycocalyx

Abstract Background Heat-not-burn cigarette (HNBC) and electronic cigarette (Ecig) constitute non-combustible smoke products. Their effect on endothelial glycocalyx has not been investigated so far. Patients and Methods: Out of 100 subjects attending smoking cessation clinic: α) 50 smokers were randomized to usage of HNBC (n=25) or Ecig (n=25) and β) 50 smokers were used as control group. Participants randomized to the newer tobacco products had similar clinical and demographic characteristics to the control group. Smoking status was verified by measuring the concentration of exhaled carbon monoxide [(e CO) (ppm), Bedfont Scientific, Maidstone, Kent UK]. Perfused Boundary Region (PBR), which is inversely related to endothelial glycocalyx thickness in sublingual arterioles (range 5–25 μm) and blood levels of cotinine, a stable metabolite of nicotine, was assessed in all participants. Exhaled CO, endothelial glycocalyx, and blood cotinine were assessed at baseline and after 1 month. Results Conventional cigarette smokers were aged: 48 ± 5 years, 53% female and used 27 ± 9 cigarettes/day, 29 ± 9 pack-years. HNBC users were aged: 46 ± 14 years, 55% female and used 26 ± 8 cigarettes/day, 30 ± 8 pack-years. Ecig users were aged: 45 ± 8 years, 51% female and used 27 ± 10 cigarettes/day, 28 ± 10 pack-years. Compared to baseline, switching to HNBC for 1 month improved only PBR20-25 (2.55±0.49 vs 2.34±0.34 μm, p=0.002). Ecig use did not alter endothelial glycocalyx in any range of microvessels throughout the study (p>0.05). In contrast, Tcig smoking for one month further worsened endothelial glycocalyx in all microvessels ranges compared to baseline (p<0.05). Blood cotinine levels were similar at baseline and after 1 month using HNBC (p=0.432), Ecig (p=0.535) or conventional cigarette (p=0.489). Compared to baseline, exhaled CO decreased in HNBC or Ecig users (mean percent change: -55% and -58% respectively p<0.001), while remained unchanged in Tcig smokers (p=0.312) at 1 month. Thus, Tcig smokers had higher CO than those who switched to HNBC or E-cig after one month (p<0.01). Conclusion Conventional cigarette users further worsened endothelial glycocalyx after continuing to smoke for one month. In contrast, smokers who switched to Ecig maintained glycocalyx integrity, while those who switched to HNBC showed modest improvement in glycocalyx integrity in microvessels ranging from 20 to 25 μm. Cotinine levels, which reflect nicotine exposure, were similar between the Tcig, HNBC and Ecig groups. Thus, endothelial glycocalyx impairment in the conventional cigarette group was independent of nicotine consumption and possibly related to greater exposure to toxic emissions, such as CO, after Tcig use than after switching to HNBC or Ecig.

Air quality in different urban hotspots in a metropolitan city in India and the environmental implication.

This research study investigates hourly data on concentrations of five major air pollutants such as particulate matter (PM10, PM2.5) and gaseous pollutants (SO2, NO2, CO) measured during 2022 at four hotspot sites (industrial site, traffic site, commercial site, harbour, and one residential site) in Chennai, India. The analysis encompasses temporal variations spanning annual, seasonal, and diurnal variations in the pollutants. Notably, PM10 and CO emerge as the predominant pollutants, with the highest concentrations at industrial and traffic sites (PM10: 67.64 ± 40.77µg/m3, CO: 1.41 ± 0.84mg/m3; traffic site: PM10: 58.67 ± 20.05µg/m3, CO: 0.99 ± 0.57mg/m3). Seasonal dynamics reveal prominent winter spikes in particulate matter (PM10, PM2.5) and carbon monoxide (CO) concentrations, while nitrogen dioxide (NO2) and sulphur dioxide (SO2) levels peak during the summer season, particularly in the harbour area. The proximity to roadways exerts a discernible influence on diurnal patterns, with traffic sites showcasing broader rush hour peaks compared to sharper spikes observed at other sites. Furthermore, distinct bimodal patterns are evident for PM10 and PM2.5 concentrations in residential and harbour areas. A common lognormal distribution pattern is identified across the studied sites, suggesting consistent air quality trends despite contrasting locations. The conditional probability function (CPF) is used in conjunction with local meteorological conditions for identifying key pollution sources in each location. The implementation of polar plots emphasizes industries as principal local sources of pollution, at industrial sites significantly contributing to PM10, SO2, and NO2 concentrations under specific wind conditions. The main objective of the present study is to facilitate a good understanding of pollutant dynamics, pollution sources, and their intricate interplay with meteorological factors, thereby contributing to the formulation and implementation of effective air pollution control and mitigation strategies.

Exposure to cooking fumes in cafeteria workers in Korean schools: a pilot study.

This study measured cooking fumes to which workers in school cafeterias may be exposed. The measurement items were respirable dust, formaldehyde, and carbon monoxide. A total of 111 samples were obtained from 55 schools. Data on variables such as school size and daily cooking oil usage were collected. Correlation and association analysis were performed. The median of concentrations of respirable dust was 38.37 µg/m3 (min-max: 20.73-49.71 µg/m3). The concentrations of formaldehyde and carbon monoxide also showed levels that did not exceed 20% for occupational exposure limits. The increase in school size was significantly correlated with the increase in daily cooking oil usage and had a significant correlation with respirable dust concentration (Spearman's correlation coefficient, 0.36; P <0.05). The linear regression test results adjusting for other variables were also similar. Cooking food by frying at high heat using cooking oil can increase the exposure of kitchen workers to respirable dust.

Peat smoke exposure as a risk factor for deterioration of postnatal development

Introduction. In connection with the growing number and scale of wildfires, the problem of the toxic effect of biomass combustion products is relevant both in Russia and abroad. Data on the consequences of wildfire smoke exposure at various stages of ontogenesis are extremely scarce. The presence in smoke substances that, in addition to general toxic effects, have reprotoxic, gonadotoxic, and genotoxic effects, determines the need to study its effect on the reproductive potential and health of offspring. The purpose of the study was to assess the postnatal development of the offspring, the parent generation of which was exposed to peat smoke during puberty. Materials and methods. Exposure to peat smoke was carried out once for four hours on the 35th day of life for female and on the 45th day for male rats. The average concentrations of carbon monoxide in the exposure chambers were 29.3±11.1 mg/m3, and ultrafine PM2.5 particles – 0.39±0.61 mg/m3. At puberty, peat smoke exposed rats were mated with intact partners. In rat pups from the offspring there was studied the trend in body weight gain, physical development, and sensory-motor reflexes were assessed. Results. Acute exposure to peat smoke during puberty in white rats adversely affects the development of their offspring. A significant lag in the physical and sensory-motor development of rat pups from the offspring of animals exposed to smoke was revealed in comparison with rat pups from the control group. Limitations. The study was limited to the study of postnatal development of offspring obtained from rats exposed to peat smoke during puberty. Conclusion. Exposure to peat smoke during puberty leads to a delay in the physical and somatosensory development of the offspring during early postnatal ontogenesis.

Integrating Flow Field Dynamics and Chemical Atmosphere Predictions for Enhanced Sulfur Corrosion Risk Assessment in Power Boilers.

In this work, we attempt to explain the phenomenon of sulfur corrosion of power boiler water walls under the conditions of large fluctuations in carbon monoxide concentrations. To assess the conditions required for corrosion formation, a criterion based on the chemical and flow field parameters of the flue gas is proposed. The formulated sulfur corrosion criterion is based on the mixture fraction variance and the turbulence time scale. Numerical modeling of coal combustion in a 250 MW power boiler is performed using ANSYS. Two cases of combustion in a boiler are analyzed, with the first simulating the boiler operated using classic high-swirl burners and the second one accounting for boiler operation with modified low-swirl burners. Calculations of pulverized coal combustion are performed using the standard k-ε turbulence model and the combustion described by the mixture fraction. The simulation results reveal that the low-swirl burner is characterized by higher values of the mixture fraction variance and a higher frequency of fluctuation of the velocity field, which is strongly related to an increased corrosion rate. The study outcomes show the validity of using the criterion of the mixture fraction variance and velocity field fluctuations to determine the areas at risk of sulfur corrosion.

Statistical modeling of the effects of wind speed, air temperature and relative humidity on the concentration of carbon monoxide in the urban atmosphere

The high carbon monoxide content in the urban atmosphere is one of the most important indicators of poor air quality in megacities such as Moscow. This study is to evaluate the importance of wind speed, air temperature, and relative air humidity for predicting the concentrations of carbon monoxide for the day ahead using a simplified one-dimensional quasistationary statistical model. It is shown that the concentration of carbon monoxide in the Moscow atmosphere is determined by a combination of internal (previous days CO concentration) and external (meteorological conditions) factors. The variation of carbon monoxide concentration at one station differs from the variation at another station due to the differences in local conditions. Taking into account wind speed and air temperature increases the predictive value of the onedimensional quasi-stationary statistical model for most of the stations. In contrast to wind, relative air humidity decreases the predictive value of the model for most of the stations. This means that meteorological factors considered in this study could have different effects on predicting carbon monoxide concentration in the case of Moscow. The data from the Balchug weather station, located in the city center, offers a more accurate CO concentration forecast for most Moscow stations compared to the VDNKh weather station. For a more complete description of the influence of meteorological conditions on the predicted low concentration of gases, it is useful to take into account the model wind direction, surface air pressure, and the intensity of mixing in the urban boundary layer.

Method for Detecting Fire Indoors Based on Differences in Sample Averages of an Arbitrary Gas Environment Dangerous Parameter at Adjacent Observation Intervals

The object of the research is the series average of the dangerous parameters of the gas environment during the ignition of materials. The practical importance consists of using the difference between the average dangerous parameters of the gas environment on the intervals of absence and the presence of ignition to detect the ignition of materials. The theoretical substantiation of the method of detecting fires in premises is carried out based on sample averages fixed samples of current measurements of an arbitrary, dangerous parameter of the gas environment, which correspond to the general population of reliable absence and presence of fire. At a given significance level, the method determines the unbiased, uniformly most powerful fire detection rule. This allows you to determine how significant differences in sample means with a given significance level are due to ignition or are random. Laboratory experiments were conducted to verify the method of detecting the ignition of test materials. It was established, for example, that the maximum size of the effect ignition on the carbon monoxide concentration is typical for alcohol (exceeds the threshold by 8.9 times) and textiles (exceeds the threshold by 9.3 times). The size of the effect of the smoke density upon ignition of all materials is approximately the same and is determined by exceeding the corresponding thresholds from 4.62 to 3.9 times. The size of the effect on the temperature of the gaseous environment during ignition of all test materials is approximately the same order. It is characterized by exceeding the corresponding thresholds from 5.95 to 3.58 times. It is shown that the method of detecting fires allows to establish the extent to which the detected differences in sample means for samples from the general population of hazardous parameters of the gas environment are reliable with a given level of significance and are due to the ignition of materials or the action of random factors.

Effectiveness of natural ventilation in controlling the smoke spread within a refuge floor of a high-rise building

Refuge floors in high-rise buildings ensure a haven for occupants to stay in an emergencyprimarily during a fire breakout. Provisions for natural ventilation of the refuge floor are mandatory in all fire codes as they help release smoke and heat build-up. However, the effectiveness of such provisions has been questioned in many studies. This research employs large eddy simulations based three-dimensional computational fluid dynamics modelling on a real-world high-rise building to investigate the efficacy of natural ventilation in a refuge floor during a fire. Consequently, the performance was assessed by evaluating the temporal and spatial distributions of temperature, visibility, smoke and carbon monoxide concentration. Emphasis was placed on determining the adequacy of window placement and openings. Analysis was started with a code-compliant window configuration. Subsequently the window size and the layout were iteratively modified using simulation results. Seasonal wind variations were also considered. Results showed that a well-engineered natural ventilation strategy can considerably improve the refuge floor habitability. Simulations also revealed limitations of natural ventilation under certain wind conditions, necessitating a backup mechanical system. This also underlined that combining fire analysis with cutting-edge modelling allows tailored natural ventilation for refuge floors, maximising safe occupancy during fires.

Daily gaseous air pollution and pediatric conjunctivitis: A case-crossover study across ten cities in China's southeastern coastal region

The evidence on associations between ambient gaseous pollutants and conjunctivitis remains inconclusive, and limited research is available, particularly regarding children. Based on a case-crossover study conducted in ten Chinese cities from 2013 to 2023, we documented 418,027 outpatient visits for conjunctivitis in children. Of these visits, 256,525 were for boys and 161,502 for girls. A one standard deviation (SD) increase in daily concentrations of carbon monoxide (CO) was related to a 1.20 % rise in same-day outpatient visits for pediatric conjunctivitis (OR = 1.012, 95 % CI: 1.005, 1.018). Similar associations were found for nitrogen dioxide (NO2: 2.90 % increase; OR = 1.029, 95 % CI: 1.019, 1.040), sulfur dioxide (SO2: 1.70 % increase; OR = 1.017, 95 % CI: 1.007, 1.028), and ozone (O3: 1.30 % increase; OR = 1.013, 95 % CI: 1.006, 1.021). The positive associations remained significant in two-pollutant and mixed-effects models. Notably, we observed stronger associations in girls compared to boys, among children at 1–5 years of age compared to other age groups, and the relationships were more pronounced during the summer months. This study reveals a link between exposure to common gaseous air pollutants and increased risks of conjunctivitis in children, indicating the potential benefits of public health interventions.

Evaluating the Impact of Renewable Energy Integration on Air Quality: A Study of Pollutant Reduction in an Urban city of Calabar

The characterization of air quality parameters was carried out in the coastal city of Calabar with the aim of reducing air pollutants in the atmosphere. Both mobile and stationary measurements were obtained. Mobile data were used for estimating air quality index and creating air quality map. The results show that the average concentration of ozone (O3), carbon monoxide (CO), sulfur dioxide (SO2) and nitrogen Oxides (NOx) was 0.34, 4.52, 0.53 and 0.96 ppm, respectively. The air quality index determined for each station showed that 82% of the stations were classified as “marginally polluted,” 14% were classified as “good,” and the remaining 4% were classified as “unhealthy” according to the U.S. air quality standards. Correlation analysis showed that wind speed had the highest correlation with SO2, R = -0.72, while temperature had a high correlation with ozone, R = -0.68. The 2016 polar plots show that CO sources are located in the south and southeast, NOx sources are located in the south and southwest, SO2 sources are located in the southwest, and O3 sources are located in the southeast. The 2017 polar plots show that CO sources are located in the northeast, NOx sources are located in the northwest, SO2 sources are located in the northeast, and O3 sources are located in the southwest.

In-tunnel pollutant concentration measurement and ventilation control indexes for highway tunnels in mountainous area: A case study of no.1 Qinling tunnel, China

The pollutant concentration and hygiene standards in mountain tunnels are key factors determining the ventilation effectiveness of tunnel operation. Previous studies have mainly focused on the spatiotemporal distribution patterns of in-tunnel pollutants, while research on ventilation control indexes for pollutants in long mountain tunnels are relatively limited. Therefore, this paper aims to discussing the hygiene control indexes for operational ventilation of mountain tunnels. Field tests were conducted in the No.1 Qinling Tunnel of Xi'an to Han zhong Highway in China, and the distribution laws of traffic flow, wind speed, and concentrations of particulate matter (PM), carbon monoxide (CO), and nitrogen oxide (NOX) were on-site measured. The spatiotemporal distribution characteristics of pollutants in the long mountain tunnel were revealed, and the ventilation hygiene control indexes for harmful gases were calculated and compared to those of urban highway tunnels. The results show that the traffic volume of operational highway tunnels in mountainous areas of China is increasing rapidly, and the particulate matter emitted from diesel vehicle exhaust will pose a threat to the normal environmental quality in the tunnel. The average value of CO base emission factor in 2000 for the upline of No.1 Qinling tunnel was 0.0019 m3/(veh·km) by back-calculation, and the annual decline rate of CO in the ventilation design for mountain highway tunnels should be 6 %–8 % and revised every 8 years. It is recommended to consider the geographical location and traffic conditions of mountain tunnels when calculating the air demand required for diluting NO2. NOx has basically replaced CO as the primary pollutant with the most significant impact on human health in mountain tunnels. It is recommended that NOX be considered as the primary hygiene control indicator in the ventilation design of mountain tunnels in China. The pollutant distribution and ventilation control indexes of mountain and urban highway tunnels are quite different, which should be treated differently in engineering applications. The research results can provide a significant reference for ventilation design and environmental evaluation of highway tunnels in mountainous areas.

Evaluating the effectiveness of the modified multi-scale multi-physics coupled model for solid oxide fuel cells: A comparative analysis

A multi-scale multi-physics coupling numerical model serves as an effective tool to study the performance and improve the efficiency of solid oxide fuel cells (SOFCs) and provides the theory and data support for optimizing SOFC structure and operational strategy. To improve the accuracy and reliability of the model, this work established a modified simulation model that considers the effect of operational, structural, and physical parameters of SOFCs. First, the electrochemical kinetics equation, multi-component diffusion lattice Boltzmann (LB) model, and heat transfer LB model are modified by incorporating the reaction gas molar fraction, gas mixture concentration, temperature, and other parameters. Second, a regional hierarchical modeling strategy is proposed, and the multi-scale coupling model is modified by coupling mass and heat transfer. Third, considering the effect of carbon monoxide molar fraction, temperature difference, concentration change and porosity on electrochemical, mass, and heat transfer processes, the effectiveness of modification model is analyzed and validated. Results demonstrate that the modified model considerably improves the numerical simulation to handle the complex operational conditions of SOFCs. The modified model's predictions show better accuracy compared with experimental data, while maintaining consistency with the trends predicted by the original numerical models.

Assessment of impacts of air pollution on people living in Ezza North close to quarry operation sites in Ebonyi State, Nigeria

Quarrying activities have become lucrative work for low income people in low income countries most found in Africa. This study aimed assess the impacts of air pollution on people living in Ezza North close to quarry operation sites in Ebonyi State, Nigeria. A descriptive cross sectional study was used and pollution level was determined with the use of calibrated Handheld GPS, Amex multiple gas meter, Sound meter and interview of participants with a questionnaire on the health status. The collected data were entered into the Statistical Package for Social Sciences (SPSS) software (version 21). The one sample T-test was used to test the hypotheses at 95% confidence interval and 0.05 level of significance. The results showed that 31–40 years had 19(5.37%) males and 20(5.65%) females as highest quarrying workers. The concentration of carbon monoxide was highest at 193ppm, Sulphur dioxide at 568ppm, nitrogen dioxide at 1.9ppm, Suspended particulate Matter (SPM) at 1982ppm and sound level at 82.9dB. The concentrations of these pollutants were found to be significantly higher (P&lt;0.05) than normal levels apart from sound level without significant impact at P = 0.285. The 93.3% of the participants reported blasting of rocks produced highest air pollution, 87.5% that reported crushing, conveying, sieving produce a lot of dust. Also, 80% of participants reported high level of noise came from machinery blasting rocks, processing and haulage trucks. In all, 35% reported they had fair health condition when asked about the health status since they started quarrying work. In conclusion, the concentrations of carbon monoxide, carbon dioxide, sulphur dioxide, particulate matter and nitrogen oxides were all higher than normal. It was observed air pollutants had association with respiratory system. Therefore, the air pollution at quarrying site can be mitigated through dust suppression techniques and treating quarry pit with water before discharging.

Development of Integrated Thermally Autonomous Reformed Methanol-Proton Exchange Membrane Fuel Cell System

This paper presents a novel thermally autonomous reformed methanol fuel cell (RMFC) system for highly efficient hydrogen production and power generation by integrating a self-heating methanol steam reforming (MSR) microreactor and a high temperature proton exchange membrane fuel cell (HT-PEMFC). The RMFC system would exhibit significant potential for portable use due to its high energy efficiency, compact size and long lifetime. The structural design of the RMFC system including MSR microreactor and HT-PEMFC are studied, and a work flow is developed to enable the startup and stable power output of the system. After that, the microreactor and HT-PEMFC are fabricated, and then integrated to develop the system. Experimental testing results showed that the microreactor can produce a maximum reformate gas of 541 ml/min with a methanol conversion larger than 93.8%., while maintaining the carbon monoxide concentration below 2%. The RMFC system can start up within 17 min, the temperature fluctuation is lower than 6.28% and the maximum output power can reach up to 32.9 W. As for a conservatively designed rating power of 25 W, the calculated energy conversion efficiency of the system can reach about 28.5%, with good stability during long-term operations.

A rhizosphere effect promotes the persistence of gas oxidization activity in soil

Labile carbon and nutrients of the rhizosphere promote the activity of trace gas oxidizing bacteria (TGOB), but the capacity of the rhizosphere effect to support their persistence upon activation has received less attention. Here, we hypothesized that the activation response of TGOB in soil before planting is proportional to the persistence of their activity after wheat growth. The TGOB were activated in sandy-loam and peat soils under a static atmosphere containing elevated concentration of hydrogen (H2), carbon monoxide (CO) or methane (CH4). Our hypothesis was proven to hold true in sandy-loam soil, whereas higher organic matter in peat soil was less favourable for the persistence of TGOB activity. We conclude that the energy potential of the trace gas oxidation reaction and soil nutrients both intervein in the persistence of TGOB activity.

Finishing bench tests for thermal neutralization of marine oily waters

The studies conducted on the ship's oily water thermal disposal test bench demonstrated, on the one hand, the suitability of the bench for research work, and on the other hand, revealed several unaccounted aspects in the design of the bench and its measuring system. Specifically, the nozzle was replaced to ensure finer atomization of the oily water into the flue. Additionally, it was previously established that lower pressure than originally designed was sufficient for proper atomization, necessitating the replacement of the control manometer and the electronic pressure sensor, followed by their calibration. To enable the calculation of the thermal energy characteristics of the thermal disposal process, a correlation between the pressure in the tank and the flow rate of the oily water through the nozzle was established. In a series of fine-tuning tests, data were collected on the temperature distribution along the length of the flue without and with the injection of both clean and oily water. The results indicate additional heat release when oily water is injected into the flue. The environmental characteristics of the thermal disposal process were monitored using a gas analyzer. In all the tests, the decrease of carbon monoxide concentration to almost zero was noted. Based on the results of the fine-tuning tests, it was concluded that the bench is ready for the following experiments: screening and interpolation.

On-demand release of CO in dual-responsive nanocomposite hydrogels for wound dressing

Gaseous signaling molecules, especially carbon monoxide (CO), hold promising potential for disease management. The therapeutic efficacy of CO is closely tied to its concentration, however, maintaining it at optimal levels for both efficacy and safety is highly challenging. To address this, we designed a dual-responsive (pH/red light) nanocomposite hydrogel for on-demand CO release. We first synthesized a hybrid nanocomposite (CaCO3@AgCCN) comprising a CO2 donor (CaCO3) and a photocatalyst (Ag3PO4-decorated carbon dot g-C3N4, AgCCN) capable of converting CO2 to CO. The size of CaCO3 particles was approximately 40 nm, while that of AgCCN was around 150 nm in this nanocomposite. CaCO3@AgCCN was then incorporated into chitosan (CS) to form a nanocomposite hydrogel. This nanocomposite hydrogel could respond to a mildly acidic environment due to bacterial growth, generating CO2 exactly where it is needed (the wound site), which would be subsequently catalytically converted to CO by AgCCN under 630-nm red light illumination to facilitate wound healing. The generated CO, readily controlled by adjusting the CaCO3@AgCCN content in the nanocomposite hydrogel and the red-light illumination time (the CO concentration reaching 4.7 μM after 10-min illumination), has demonstrated strong bactericidal and anti-inflammatory effects, both essential in facilitating wound healing as shown in both in vitro and in vivo studies. Coupled with satisfactory biocompatibility, this dual-responsive nanocomposite hydrogel appears to hold great promise for safe and effective applications of CO in biomedical fields.

Mechanism of Carbon Monoxide (CO) Generation and Potential Human Health Hazard during Mechanized Tunnel Driving in Organic-Rich Rocks: Field and Laboratory Study

The monitoring of carbon emissions is increasingly becoming a sustainability issue worldwide. Despite being largely unnoticed, the toxic gas carbon monoxide (CO) is ubiquitous in mechanized tunnel driving, but the individual sources, release and enrichment mechanisms are often unknown. In this study, the generation of CO from organic matter containing sedimentary rocks was investigated during mechanized tunnel driving and by reacting claystone and sandstone with 10 mM NaCl solutions for 2 months at 70 °C and 140 °C. The mineralogical and geochemical evolution of the solids and fluids was assessed by CO measurements and the XRD, DTA, TOC, IC and ICP-OES methods. The CO concentration in the atmosphere reached up to 1920 ppm (100 ppm on average) during tunnel driving, which is more than three times higher than the legal daily average dose for tunnellers, thus requiring occupational safety operations. Mineral-specific dissolution processes and the rapid decomposition of labile organic matter upon thermal alteration contributed to the liberation of CO and also carbon dioxide (CO2) from the host rocks. In mechanized tunnel driving, frictional heat and ‘cold’ combustion with temperatures reaching 50–70 °C at the drill head is an important mechanism for increased CO and CO2 generation, especially during drilling in sedimentary rocks containing significant amounts of OM and when the ventilation of the tunnel atmosphere and air mixing are limited. Under such conditions, human health damage due to CO exposure (HHDCO) can be 30 times higher compared to tunnel outlets, where CO is emitted from traffic.

Constructing CO-immune water dissociation sites around Pt to achieve stable operation in high CO concentration environment

The serious problem of carbon monoxide (CO) poisoning on the surface of Pt-based catalysts has long constrained the commercialization of proton exchange membrane fuel cells (PEMFCs). Regeneration of Pt sites by maintaining CO scavenging ability through precise construction of the surface and interface structure of the catalyst is the key to obtaining high-performance CO-resistant catalysts. Here, we used molybdenum carbide (MoCx) as the support for Pt and introduced Ru single atoms (SA-Ru) at the Pt-MoCx interface to jointly decrease the CO adsorption strength on Pt. More importantly, the MoCx and SA-Ru are immune to CO poisoning, which continuously assists in the oxidation of adsorbed CO by generating oxygen species from water dissociation. These two effects combine to confer this anode catalyst (SA-Ru@Pt/MoCx) remarkable CO tolerance and the ability to operate stably in fuel cell with high CO concentration (power output 85.5 mW cm−2@20,000 ppm CO + H2 – O2), making it possible to directly use the cheap reformed hydrogen as the fuel for PEMFCs.