Carbon Monoxide Concentrations Research Articles

Densification versus urban sprawl. Modeling the impact of two urban growth scenarios on air quality

This study analyzes the impact of urban form on air pollution for two urban growth scenarios in 2040 for Quito, Ecuador: Urban sprawl (low-density outward expansion) and densification (the population increase occurs within the 2017 city boundaries). We estimate concentrations of carbon monoxide (CO), nitrogen oxides (NOx), nitrogen dioxide (NO2), ozone (O3), and particulate matter with an aerodynamic diameter equal to or less than 2.5 μm (PM2.5). Two downscaled global emission pathways (ECLIPSE) that present a lower/upper range are applied: 1) Current legislation emissions, CLE, and 2) Maximum technically feasible reductions, MTFR. The population is expected to increase by 50%, from 3 million in 2017 to 4.5 million in 2040. The sprawl scenario considerably increases the urban area by 52%. However, these new areas hold only 9% of the population. Both pathways present considerably lower emissions for 2040 than in 2017. Emissions for all sectors, except transportation, are the same for both scenarios. Transport emissions for the densification scenario are 32% lower than for urban sprawl.Due to reduced emissions, the 2040 scenarios result in lower CO, NOx, and PM2.5 concentrations for both pathways compared to 2017. This drop is more marked for the MTFR pathway compared to CLE. Contrary to our expectations, the two scenarios result in similar annual concentrations at the metropolitan level. Even when emission variations are considerable, differences between the scenarios are relatively small, particularly for CO, O3, and PM2.5, due to high regional contributions. However, the spatial distribution of concentrations within urban areas differs significantly; thus, the sprawl scenario results in a larger surface with higher CO, NOx, NO2, and PM2.5 levels and the opposite for O3. Still, due to the population distribution, the densification scenario exposes more residents to higher CO, O3, and PM2.5 values, and the sprawl scenario exposes more inhabitants to higher concentrations of NO2 and NOx.We find an improvement in air quality for both scenarios in 2040 compared to 2017. The annual average NO2 concentrations exceed local regulations in a small urban area only for the CLE pathway. In contrast, for PM2.5, the area and population exposed to levels that exceed the local regulation are higher than that for NO2 and more significant for the densification than the sprawl scenario and for the CLE than the MTFR pathway.

Long-term field calibration of low-cost metal oxide VOC sensor: Meteorological and interference gas effects

This study aimed to evaluate the performance of the Sensirion SGP30 MOS (metal oxide semiconductor) VOC sensors (SMVSs) for a long sampling period (10–12 months) at different ambient air monitoring stations (AQMSs). In the field tests, temperature (T), relative humidity (RH), carbon monoxide (CO) concentration, and non-methane hydrocarbons (NMHC) concentrations were found to be the crucial parameters influencing the sensor readings. A multiple linear regression (MLR) calibration model using hourly T, RH, CO, and VOC values as parameters was developed at Zhongming (ZM) station and validated at Hsinchu (HC) and Tainan (TN) stations. After calibration, the SMVS performance was improved significantly with the decrease of mean normalized bias (MNBs) and mean normalized errors (MNEs) of hourly-average data from +228 to 473% to ±25.9% and 231–473%–47.2%, respectively based on the reference NMHC values in the AQMSs. For ambient NMHC concentrations higher than 100 ppbv, the MLR-calibrated results were further improved with MNBs (MNEs) less than ±20% (28.3%). The correlation between calibrated sensor data and reference data was enhanced significantly with the R2 values increasing from 0.27 to 0.50 to 0.65–0.78 at three stations. Therefore, these well-calibrated sensors can become viable tools for many purposes including hotspot identification and characterization, and personal exposure study (MNE<30%).

Quantifying anomalies of air pollutants in 9 U.S. cities during 2020 due to COVID-19 lockdowns and wildfires based on decadal trends

The COVID-19 pandemic led many state and local governments in the United States to enact lockdowns to control the spread of the virus. These actions led to lower on-road emissions as a significant portion of the workforce began working from home. Here, we examine the concentrations of primary pollutants, nitrogen dioxide (NO2) and carbon monoxide (CO), a secondary pollutant, ozone (O3), and one that is both a primary and secondary pollutant, particulate matter (PM2.5), from 9 U.S. cities in 2020 using data reported to the U.S. Environmental Protection Agency to determine how they changed during the pandemic. We used a multiple linear regression model fitted to historical data to account for meteorology and found concentrations of NO2, O3, and CO generally decreased in the 9 cities in late March and early April, consistent with previous literature and a fuel-based emissions inventory. We further found the decadal trends of the 4 pollutants were decreased in the summer months for most of the cities studied. An analysis of weekend decreases in NO2 was consistent with previous studies; however, the weekend increases in O3 were typically dominated by reduced NOx titration. We further detect anomalous increases in NO2, CO, O3, and PM2.5 in western U.S. cities in the late summer, which we attribute to wildfire emissions. Finally, we examined diel profiles to determine when changes due to COVID-19 lockdowns and late-summer wildfires were most apparent during the day.

Ambient carbon monoxide and the risk of cardiovascular disease emergency room visits: a time-series study in Lanzhou, China.

Until now, the epidemiological evidence on the association between short-term exposure to ambient carbon monoxide (CO) and cardiovascular diseases (CVDs) is relatively lacking and controversial. This study aims to examine the relationship between ambient CO and daily emergency room visits (ERVs) for total and cause-specific CVD in Lanzhou, China. A distributed lag nonlinear model was used to examine the association. For every 1mg/m3 increase in the CO concentration, the relative risks of daily ERVs were 1.041 (95% CI: 1.017, 1.065) for total CVD, 1.065 (95% CI: 1.018, 1.114) for ischemic heart disease (IHD), 1.083 (95% CI: 1.020, 1.149) for heart rhythm disturbances (HRD), 1.062 (95% CI: 1.011, 1.115) for heart failure (HF), and 1.057 (95% CI: 1.017, 1.098) for cerebrovascular diseases (CD). For the two different gender subgroups, the short-term impact of CO on total CVD, IHD, and CD was relatively stronger for the females than for the males, while the opposite was true for HRD and HF. In the age subgroup analyses, the effect of ambient CO on total CVD and IHD appeared to be greater for the age ≥ 65years group, while the opposite was true for HRD, HF, and CD. The associations for all disease categories were stronger in cold seasons than in warm seasons. We also observed a nearly linear correlation between CO and CVD ERVs. In conclusion, the study showed that exposure to ambient CO may increase the risks of ERVs for total and cause-specific CVD. Besides, CO-ERVs associations may vary by gender and age.

Systematic review and meta-analysis investigating nicotine, cotinine and carbon monoxide exposures in people who both smoke and use nicotine replacement therapy.

To determine effects of concurrent smoking and nicotine replacement therapy (NRT) use on reported heaviness of smoking, nicotine (cotinine) body fluid and exhaled air carbon monoxide (CO) concentrations. Systematic review and meta-analysis of RCTs, which test interventions permitting concurrent NRT use and smoking and comparing, within participants, outcomes when smoking with those when smoking and using NRT concurrently. Measurements included reported number of cigarettes smoked per day (CPD), body fluid cotinine and expired air CO concentrations. Twenty-nine studies were included in the review. Meta-analysis of nine showed that, compared with when solely smoking, fewer cigarettes were smoked daily when NRT was used (mean difference during concurrent smoking and NRT use, -2.06 CPD [95% CI = -3.06 to -1.07, P < 0.0001]). Meta-analysis of seven studies revealed a non-significant reduction in exhaled CO during concurrent smoking and NRT use (mean difference, -0.58 ppm [95% CI = -2.18 to 1.03, P = 0.48]), but in the three studies that tested NRT used in the lead-up to quitting (i.e. as preloading), a similar reduction in exhaled CO was statistically significant (mean difference, -2.54 ppm CO [95% CI = -4.14 to -0.95, P = 0.002]). Eleven studies reported cotinine concentrations, but meta-analysis was not possible because of data reporting heterogeneity; of these, seven reported lower cotinine concentrations with concurrent NRT use and smoking, four reported no differences, and none reported higher concentrations. People who smoke and also use nicotine replacement therapy report smoking less heavily than people who solely smoke. When nicotine replacement therapy is used in the lead-up to quitting (preloading), this reported smoking reduction has been biochemically confirmed. There is no evidence that concurrent smoking and nicotine replacement therapy use result in greater nicotine exposure than solely smoking.

Systematic review and meta-analysis investigating nicotine, cotinine, and carbon monoxide exposures in people who both smoke and use nicotine replacement therapy.

Smoking is a major international public health problem. To determine effects of concurrent smoking and nicotine replacement therapy (NRT) use on reported heaviness of smoking, nicotine (cotinine) body fluid, and exhaled air carbon monoxide (CO) concentrations. Systematic review and meta-analysis of randomised controlled trials (RCTs) that test interventions permitting concurrent NRT use and smoking, and comparing, within participants, outcomes when smoking with those when smoking and using NRT concurrently. In total, 29 studies were included in the review. Meta-analysis of nine showed that, compared to when solely smoking, fewer cigarettes were smoked daily when NRT was used (mean difference during concurrent smoking and NRT use, -2.06 CPD [95% confidence interval {CI} = -3.06 to -1.07, P<0.0001]). Meta-analysis of seven studies revealed a non-significant reduction in exhaled CO during concurrent smoking and NRT use (mean difference, -0.58 ppm [95% CI = -2.18 to 1.03, P = 0.48]), but in the three studies that tested NRT 'preloading', a similar reduction in exhaled CO was statistically significant (mean difference, -2.54 ppm CO [95% CI = -4.14 to -0.95, P = 0.002]). Overall, 11 studies reported cotinine concentrations, but meta-analysis was not possible due to data reporting heterogeneity; of these, seven reported lower cotinine concentrations with concurrent NRT and smoking, four reported no differences, and none reported higher concentrations. People who smoke but who also use NRT reported smoking less heavily than when solely smoking, and when NRT was used as 'preloading' this reported smoking reduction was biochemically confirmed. There was no evidence concurrent smoking and NRT use resulted in greater nicotine exposure than smoking.

Research of diesel bus performance when using diesel biofuel

Problem. The article focuses on the use of diesel biofuel to expand the fuel base and improve ecological indicators of diesel buses. Goal. The study aimed to refine the mathematical model of bus movement in urban driving modes to determine fuel-economic and ecological indicators of the bus when using traditional diesel fuel and diesel biofuel. Methodology. Experimental studies were conducted on motor-tractor diesel 4CH11.0/12.5 (D-241) to determine its fuel economy and ecological indicators when running on both fuels, checking the adequacy of polynomial models of the diesel. Practical tests were performed on PAZ-32054 buses with diesel engines to verify the refined mathematical model on both fuels. Results. The study showed that diesel biofuel could be used in motor-tractor diesel engines without requiring any changes in their construction. However, hourly and specific consumption of diesel biofuel increased by 11-16% compared to traditional diesel fuel across a wide range of speed and load modes. The concentrations of carbon monoxide (CO) and hydrocarbons (CmHn) varied depending on the diesel engine's load. With an increase in the load, the concentrations of CO and CmHn were lower by 3% and 23%, respectively, compared to traditional diesel fuel. The study concludes that diesel biofuel is a practical alternative for diesel engines, which can be an important step towards improving the ecological situation in urban areas. By reducing the consumption of traditional diesel fuel, diesel biofuel can also help in diversifying the fuel base of diesel buses. Originality. The originality of the study lies in its experiments to prove the practical use of diesel biofuel in diesel engines and in demonstrating its ecological benefits. Practical value. The practical significance of the study is the possibility of using diesel biofuel in existing diesel engines without the need for major changes to the engine's construction.

Modelling the reduction of quartz in a quartz–carbon pellet

Traditional refining of silicon generates carbon dioxide emissions that are released into the atmosphere. An alternative process under experimental exploration uses quartz particles coated in a layer of porous carbon as the raw material, instead of lumps of quartz and carbon. The quartz–carbon pellets are processed at a lower temperature than in an industrial furnace, and hence, different chemical reactions are dominant, reducing the greenhouse gas emissions. The quartz core shrinks as it is consumed, and the carbon is converted to silicon carbide, which can subsequently be processed into silicon. We develop a model for chemical and transfer processes within a single quartz–carbon pellet. We derive governing equations for the concentration of silicon monoxide, carbon monoxide, and carbon dioxide, and conservation equations on the moving quartz interface. Furthermore, we then focus on a reduced model in an industrially relevant distinguished limit, and solve numerically the resulting leading-order system. We show examples of reaction-limited behaviour as well as diffusion-limited behaviour. Both regimes are physically admissible due to the large potential range of the parameters. Finally, we sweep through the parameter space, and characterize the dynamics based on the utilization of the carbon and the silicon yield. We find that the diffusion-limited regime is best for carbon utilization and silicon yield, as the silicon monoxide reacts with the carbon before it is transported out of the pellet.

Status of atmospheric air pollution in Ukraine prior to the full-scale russian invasion. Part 1: ground-level content of pollutants

The paper is dedicated to examination of atmospheric air pollution in Ukraine that is aimed at establishing basic air quality conditions prior to the full-scale Russian invasion. Analyses cover five air pollutants (dust, sulfur dioxide (SO2), carbon monoxide (CO), nitrogen dioxide (NO2), and formaldehyde (CH2O)) across 126 monitoring stations in 39 cities. It was found that the most dangerous excess of air pollution levels in cities was associated with dust, NO2, and CO. At the same time, SO2 content usually did not reach dangerous levels. The highest frequency of exceeding the threshold one-time levels was common for the cities with well-developed industrial facilities. Dangerous air pollution was observed in 15–60% of cases, depending on a pollutant. Dust and NO2 concentrations of the most polluted cities were 10 times higher than their concentrations in smaller cities having no significant industrial emissions. The difference in average CO, SO2, and CH2O concentrations among monitoring stations constituted 3-5 times. We studied the patterns of pollutants' seasonal variability recorded at the monitoring stations. Normally, no significant seasonality except for CH2O and dust was observed. The interannual variability of pollutants, emissions, and their trends were analyzed for the period since 2008. We identified a certain discrepancy in trends between pollutants’ concentrations and emission data over the last years. Pollutant content often continued to grow concurrently with emission reductions. The impact of atmospheric phenomena and wind parameters was studied mainly in terms of its role in formation of high and low atmospheric pollution levels. The analysis indicated a crucial role of local conditions in the formation of an atmospheric pollution field next to monitoring stations. Varying atmospheric pollution values across different monitoring stations within a specific city can be different even under the influence of the same atmospheric phenomena. The wind impact also formed different patterns of atmospheric pollution within same city. 12% to 22% of all monitoring stations (depending on a pollutant) indicated a prevailing impact of a single emission source (or a combined impact of a group of sources). At the same time, air pollution at other monitoring stations was highly variable, with elevated pollution levels being transported from numerous directions. The analysis of the air pollution-affected condition presented in the paper could be used as a basis for comparing ground-level pollution and assessing the warfare consequences in Ukraine. The research emphasizes the importance of updating the information about ground-based monitoring stations.

Revealing the peculiarities of asymmetry and kurtosis coefficients of gas medium parameters in premises during fire

The object of the study is the coefficients of asymmetry and excess of the selective distribution of hazardous parameters of the gas environment during material fires. The practical importance of the research lies in the use of measures of asymmetry and kurtosis for early detection of fires. The measures of asymmetry and kurtosis for sampling the final size of an arbitrary dangerous parameter of the gas environment are substantiated. The proposed measures make it possible to investigate the peculiarities of the coefficients of asymmetry and kurtosis in relation to the selective distribution of an arbitrary dangerous parameter of the gas environment. At the same time, it becomes possible to numerically determine the degree of difference of the sample distributions of dangerous parameters from the Gaussian, as well as the features of such measures. Experiments were conducted to determine the degree of asymmetry and excess of dangerous parameters of the gas environment in the laboratory chamber at the intervals of the absence and presence of ignition of the test materials. The obtained results indicate that on the intervals of absence and presence of fires, the selective distributions of dangerous parameters of the gas environment differ from the Gaussian distribution. Distributions are complex and individual in nature. Features of measures of asymmetry and kurtosis depend on the type of ignition material. It was established that the maximum values of the modulus of increase in the degree of asymmetry are characteristic for the carbon monoxide concentration (2.939) during the ignition of paper, for the smoke density (3.098) during the ignition of textiles, as well as for the temperature during the ignition of alcohol (7.163) and wood (1.06). It was determined that the maximum values of the modulus of excess measure increase are characteristic for smoke density (4.678) when paper, wood (1.652) and textiles (28.932) ignite, as well as for temperature (49.377) when alcohol ignites

THE INFLUENCE OF THE ELECTRODE TYPES ON THE CARBON MONOXIDE FORMATION DURING THE WELDING PROCESS

A study on the dependence of the carbon monoxide concentration in the working area on the magnitude of the welding current and welding time while using electrodes of different types was conducted in order to choose the methods and means for the protection of welders. An analysis of the latest research and publications on air pollution in the working area by aerosols and gases generated during arc welding was performed. For the experimental determination of carbon monoxide concentrations in the welding area, an individual gas detector-analyzer was used. The research results conducted during arc welding in laboratory conditions using the full factorial planning of the FFE2 type experiment are presented. Based on the obtained regression models, graphical dependences of carbon monoxide concentration in the working area on the welding current and welding time were constructed when using the most common brands of electrodes. It was established that the largest amount of carbon monoxide is formed during welding at a current of 200 A with electrodes having a rutile-cellulose coating, in second place - with electrodes having a basic coating, and in third place - having rutile coating; after 5 minutes of welding with an electric current of 100 A, a larger amount of this gas is formed when using the electrodes having the basic coating. The obtained dependences make it possible to practically choose welding modes that ensure minimum levels of carbon monoxide emissions. A complex of modern solutions for reducing air pollution in the working area with carbon monoxide is given, which consists in the use of neutralization methods, ventilation means, and the use of appropriate means of individual respiratory protection, as well as controlling the air environment state during work.

Low temperature pyrolysis of polylactic acid (PLA) and its products

The fact that polylactic acid (PLA) is not biodegradable makes it necessary to find the methods of effective treatment of its waste. A significant method of processing waste PLA can be slow low-temperature pyrolysis, providing mostly oil and energy gas. The PLA pyrolysis provides almost 50 wt.% oil and 21–23 wt.% energy gas with a high carbon monoxide content above 90 vol.% at temperatures up to 420 °C. The temperatures above 420 °C do not give acceptable yields of oil anymore, and at the same time there are higher losses due to the release of low boiling aldehydes and ketones. The obtained oil and gas showed an acceptable calorific value as a basis for their use as substitute fuels. Due to its composition, oil can also be considered as a source of valuable chemicals (tetrahydrofuran, paraldehyde, cyclopentanone and ether) and gas as a source of carbon monoxide for industrial applications and, more recently, for biomedical use. Even plastic waste mixtures with a high proportion of PLA in a 1:1 ratio can be efficiently processed by slow low-temperature pyrolysis. The pyrolyzed mixture showed very similar yields of solid carbonaceous residue and oil (38 wt.% and 35 wt.%). The composition of the solid phase was only minimally different from the low-temperature pyrolysis of PLA. Although the ratio of PLA:LPO components was 1:1, the CO content decreased by ca. 20 vol.% at the expense of CO2 and lighter C2-C5.

Characteristics of Air Pollutant Distribution and Sources in the East China Sea and the Yellow Sea in Spring Based on Multiple Observation Methods

The composition of marine aerosol is quite complex, and its sources are diverse. Across the East China Sea (ECS) and the Yellow Sea (YS), multi-dimensional analysis of marine aerosols was conducted. The characteristics of carbonaceous aerosols and gaseous pollutants were explored through in situ ship-based observation, MERRA-2 reanalysis datasets and TROPOMI data from Sentinel-5P satellite. Black carbon (BC)’s average concentration is 1.35 ± 0.78 μg/m3, with high-value BC observed during the cruise. Through HYSPLIT trajectory analysis, sources of BC were from the northern Eurasian continent, the Shandong Peninsula, the ECS and Northwest Pacific Ocean (NWPO). The transport of marine sources like ship emissions cannot be ignored. According to the absorption Angstrom exponent (AAE), BC originates from biomass burning (BB) in the shortwave band (~370 nm) and from fossil fuel combustion in the longwave band (~660 nm). Organic carbon (OC), sulfate (SO42−) and BC report higher Angstrom exponent (AE) while dust and sea salt reveal lower AE, which can be utilized to classify the aerosols as being fine- or coarse-mode, respectively. OC has the highest AE (ECS: 1.98, YS: 2.01), indicating that anthropogenic activities could be a significant source. The process of biomass burning aerosol (BBA) mixed with sea salt could contribute to the decline in BBA’s AE. Ship emissions may affect the distribution of tropospheric nitrogen dioxide (NO2) in the ECS, especially during the COVID-19 pandemic. Tropospheric NO2 over the YS has the highest value (up to 12 × 1015 molec/cm2). Stratospheric NO2 has a ladder-like distribution from north to south, and the variation gradient was lower than that in the troposphere. Carbon monoxide (CO) accumulates in the south and east of the ECS and the east of the YS, while the variation over the eastern YS is relatively frequent. Seas near the Korean Peninsula have extremely high CO concentration (up to 1.35 × 1017 molec/cm2).

Environmental modelling of CO concentration using AI-based approach supported with filters feature extraction: A direct and inverse chemometrics-based simulation

This study explored the first direct and inverse modelling of Carbon monoxide (CO) concentration by applying three different computational approaches namely, Least Square-boost (L-Boost), Hammerstein Weiner (HW), and Multi-variate regression (MVR) models for modelling CO using Sulphur dioxide (SO2), Nitrogen dioxide (NO2) and Ozone (O3). Two filters feature extraction methods were used in the input-combinations selection, which was classified into the direct modelling approach (C1) and inverse modelling approach (C2). Four different statistical metrics, including Nash-Sutcliffe efficiency, Person correlation coefficient, mean absolute error and mean absolute percentage error was used in evaluating the performance of the models. Based on the performance skills of the models, it is indicated that the direct modelling approach showed superior performance to the inverse approach. Furthermore, the non-linear models (HW and L-Boost) depict higher performance skills than the linear MVR model. Overall, the L-Boost-C1 models showed higher performance based on statistical metrics.

Smoke toxicity to the biota and the biological activity of soils when modeling fires

The paper presents the results of our study on the effect of one type of pyrogenic factor (smoke) after burning coniferous wood chips on several bioindicators (soil enzymes, microorganisms, mesofauna, plants of agricultural crops). Exposition to smoke for 60 minutes was found to significantly affect the enzymatic activity of common chernozem. Fumigation caused a decrease in such enzymes as catalase, peroxidase, polyphenol oxidase and invertase. The enzymes of the oxidoreductase class were the most sensitive to smoke. High toxicity of gaseous combustion products to the soil flora and fauna was revealed. The acute toxicity of smoke to the bioindicators was determined as a result of fumigation. High mortality of test objects (Eisenia fetida, Nauphoeta cinerea) was recorded in our experiments. Soil microorganisms (Azotobacter chroococcum and Penicillium chrysogenum) proved to be informative after 30–120 minutes of fumigation. Resistance of plant sprouts (Raphanus sativus, Triticum aestivum, and Pisum sativum) to combustion gaseous products was revealed. An experiment to analyze the chemical composition of gases in smoke was performed. Such hazardous compounds as sulphur dioxide (SO2), nitrogen oxide and dioxide (NO, NO2), carbon monoxide (CO), acetaldehyde (C2H4O), formaldehyde (CH2O), phenol (C6H6O) hydroxybenzene and others were found to be contained therein. Our analysis revealed that the concentrations of carbon monoxide were 714 times higher than its maximum permissible concentration (MPC), which acetaldehyde was 24,100 times higher. The nitrogen oxide and nitrogen dioxide concentrations were 100 and 300 times higher, respectively.

Carbon Monoxide Production during Bio-Waste Composting under Different Temperature and Aeration Regimes.

Despite the development of biorefinery processes, the possibility of coupling the "conventional" composting process with the production of biochemicals is not taken into account. However, net carbon monoxide (CO) production has been observed during bio-waste composting. So far, O2 concentration and temperature have been identified as the main variables influencing CO formation. This study aimed to investigate CO net production during bio-waste composting under controlled laboratory conditions by varying aeration rates and temperatures. A series of composting processes was carried out in conditions ranging from mesophilic to thermophilic (T = 35, 45, 55, and 65 °C) and an aeration rate of 2.7, 3.4, 4.8, and 7.8 L·h-1. Based on the findings of this study, suggestions for the improvement of CO production throughout the composting process have been developed for the first time. The highest concentrations of CO in each thermal variant was achieved with an O2 deficit (aeration rate 2.7 L·h-1); additionally, CO levels increased with temperature, reaching ~300 ppm at 65 °C. The production of CO in mesophilic and thermophilic conditions draws attention to biological CO formation by microorganisms capable of producing the CODH enzyme. Further research on CO production efficiency in these thermal ranges is necessary with the characterization of the microbial community and analysis of the ability of the identified bacteria to produce the CODH enzyme and convert CO from CO2.

Sensor based real time air pollutants monitoring for an urban industrial area

&#x0D; &#x0D; &#x0D; &#x0D; Introduction: This study used economical sensors and an Unmanned Aerial Vehicle (UAV) to examine real-time air pollution assessment for an urban industrial area.&#x0D; &#x0D; &#x0D; &#x0D; &#x0D; Materials and methods: Using a DJI Phantom 3 Pro, the concentrations in the research area were measured. In the study, Carbon monoxide (CO) and Nitrogen dioxide (NO2) were measured using metal oxide sensors, and Particulate Matter (PM10) was determined using a dust smoke particle sensor. Pollutants were measured at heights of 0.8 m and 10 m for a period of one month.&#x0D; &#x0D; &#x0D; &#x0D; &#x0D; Results: With an increase in elevation, a gradual drop in pollutant concentration has been seen. High traffic volumes and fuel combustion are to blame for this increase. The concentration of CO, NO2 and PM10 at 0.8 m has been found to be 22.53%, 42.90% and 45.86% respectively higher when compared at 10 m. The main finding of this study is the use of an UAV integrated with sensors for vertical monitoring of the pollutant concentration.&#x0D; &#x0D; &#x0D; &#x0D; &#x0D; Conclusion: The CO concentration was found to be less than the standard value but near to it, when the data were compared to the Central Pollution Control Board (CPCB) standards. While it was discovered that the measured PM10 concentration was higher than the CPCB standard value, the observed NO2 concentration was determined to be lower than the standard value. Also, given that they produce satisfactory results, low-cost gas sensors can be employed to conduct concentration measurement studies.&#x0D; &#x0D; &#x0D; &#x0D; &#x0D; &#x0D; &#x0D; &#x0D; &#x0D; &#x0D; &#x0D; &#x0D; &#x0D; &#x0D; &#x0D; &#x0D;

Studies of Engine Performance and Emissions at Full-Load Mode Using HVO, Diesel Fuel, and HVO5

The aim of the study was to determine impact of commercially available hydrotreated vegetable oil (HVO) and its mixture (HVO5, where 5% (v/v) HVO and 95% (v/v) FDD) with diesel fuel (FDD) on the power, torque, fuel consumption, and exhaust gas composition of an atmospheric internal combustion diesel engine used in off-road applications. Diesel fuel was used as the comparative fuel. Testing was realized in a full-load mode on the KOHLER KDI 1903 M 3-cylinder diesel engine on a SIERRA CP-Engineering engine test bench. The AVL SESAM FTIR exhaust gas analytical system was used to determine exhaust gas emissions, while the AVL KMA Mobile fuel consumption measuring device was used to measure fuel consumption. Research showed that the lowest power and torque readings were obtained with FDD, while HVO showed a slightly higher result compared to the fossil diesel fuel. At the same time, the highest hourly fuel consumption was observed running on HVO5, while the lowest was observed with FDD. Increases in carbon monoxide (CO), carbon dioxide (CO2), and nitrogen oxide (NOx) emissions were observed for HVO5 compared to those of FDD. The CO content in emissions increased by an average of 3.0% using HVO and by an average of 36% using HVO5, but the NOx content in the emissions increased by an average of 3.0% using HVO and by an average of 8.8% using HVO5. The reduction by an average of 60% using HVO in emissions was found in the case of hydrocarbons (HC). Research confirmed that the physicochemical properties of HVO could leave an impact on the main engine performance parameters and exhaust emissions.

Combustion of pellets produced from corn straw and cashew nut shell in residential and industrial scenarios: Chemical, thermal and emission analyses.

The Brazilian Northeast region has considerable agricultural potential for corn and cashew nuts production. Residues from these cultures can be densified into pellets and used as heat generators in industries and homes. In this study, corn straw pellets (CSP) and cashew nut shells pellets (CNSP) were handmade, together with a variation using glycerol as a binder (CSGP and CNSGP). All pellets were subjected to chemical, thermal and exhaust gas analyses of their combustion. All analyses were based on two different scenarios: (i) the use of CSP and CSGP for energy supply in residential use and (ii) the use of CNSP and CNSGP for energy supply in industrial use. All pellets were subjected to chemical, thermal and exhaust gas analyses of their combustion. Chemical analysis involved the study of various fuel properties, comprehending moisture content (%U), bulk density (kg m-3), volatile materials (%V), ash content (%C) and fixed carbon (%FC), and all evaluated pellets met two or more international trading standards. The combustion process analyses in the residential scenario showed higher average temperatures and lower carbon monoxide (CO) and nitrogen oxide (NOx) concentrations obtained during CSP combustion than those of CSGP, and in the industrial scenario showed average similar temperatures and lower CO and NOx concentrations obtained during CNSP combustion than those of CNSGP. Ours results demonstrate the great potential of corn straw and cashew nut shells as crops to be integrated into the biomass supply chain for energy generation and agro-ecological development.

Remote Sensing Surveillance of NO2, SO2, CO, and AOD along the Suez Canal Pre- and Post-COVID-19 Lockdown Periods and during the Blockage

This study investigates the impact of the COVID-19 pandemic and the Ever Given ship blockage on the air quality in Suez Canal region. Nitrogen dioxide (NO2), sulfur dioxide (SO2), carbon monoxide (CO), and aerosol optical depth (AOD) were studied, and data were obtained from satellite instruments. The study compared monthly average data for 2020, 2021, and 2022 with a baseline period of 2017–2019 to investigate the pandemic’s effect. The study also analyzed the corresponding period of the canal blockage to identify its impact on air pollution levels. The pandemic had a significant role in decreasing NO2 by 2.5 × 1014 molecule/cm2 and SO2 by 0.05 DU due to reduced car traffic and industrial activities. A reduction in AOD by 20% and CO concentration in the range from 3.5% to 4.7% was reported in early 2020. During the blockage, NO2 and SO2 levels decreased by 14.4% and 66.0%, respectively, while CO and AOD index increased by 12.68% and 51.0%, respectively. The study concludes that the containment measures during the pandemic had a positive impact on the environment, which shows how the reduction in the anthropogenic activities, especially industrial and transportation activities, have improved the air quality. Thus, stricter actions are needed to protect the environment; for example, the transition towards the using of electric vehicle is necessary, which is part of Egypt’s strategy to transition towards a green economy. The government should also adopt a policy to trade carbon emissions reduction certificates to help reduce air pollution.