Oxidation Of Carbon Monoxide Research Articles

An oxidation-adsorption site separation strategy for stabilizing Pd-Pt/SSZ-13 PNA materials under high CO pressure

Pd/SSZ-13 passive NOx adsorbers (PNAs) are effective in controlling NOx emissions during the cold start phase of diesel engines, but palladium ions readily aggregate in the presence of carbon monoxide (CO), leading to irreversible deactivation. Herein, we demonstrate a simple Pd-Pt cohabitation strategy on SSZ-13 to address this issue. Co-impregnation of Pd and Pt precursors followed by calcination results in nearly 90 % of palladium existing as Pd2+ ions and the majority of platinum forming nanoparticles in close proximity to Pd2+. This close spatial arrangement creates a synergistic mechanism where Pt nanoparticles effectively oxidize CO to CO2, preventing the reduction of Pd2+ ions by CO and subsequent Pd aggregation during PNA testing in the presence of CO. More specifically, Pd-ion reduction by CO occurs above ∼200 °C; complete CO oxidation by Pt below this threshold temperature leads to the best Pd-ion protection. Finally, remaining issues regarding the development of CO-resistant PNA materials are discussed.

Controlling the trans effect induced by nitric oxide and carbon monoxide: H93C myoglobin versus H-NOX sensors and soluble guanylate cyclase.

Myoglobin (Mb) has been engineered to replace the proximal histidine (His93) with a cysteine in order to investigate the trans effect induced by diatomic ligands using time-resolved electronic absorption spectroscopy. This single mutation induces a change of heme coordination state and bonding character which change carbon monoxide (CO) and nitric oxide (NO) dynamics. In H93C Mb the increased Fe2+-S distance weakens this bond which is replaced with a distal Fe2+-His64 ligation. We measured dynamics very different from wild type Mb but similar with those measured in soluble guanylate cyclase (sGC). Whereas NO induces a direct negative trans effect, the strain on His64 ligation is sufficient to counteract the positive trans effect due to CO. After photodissociation, geminate recombination of NO to the transient 4-coordinate heme of H93C occurred with a fast time constant (6.9 ps) identical to that in sGC. Remarkably, we also observed picosecond geminate rebinding of CO to H93C Mb, similarly with sGC in the simultaneous presence of CO and an allosteric stimulator. This CO rebinding dynamics to the 4c-heme in H93C Mb was never measured in other Mb mutants and demonstrates the existence of 5-coordinate heme with CO, explaining the synergistic activation of sGC in presence of CO and a stimulator.

Recent Advances in NO Reduction with NH3 and CO Over Cu-Ce Bimetallic and Derived Catalysts

Sintering flue gas contains significant amounts of harmful gases, such as carbon monoxide and nitrogen oxides (NOx), which pose severe threats to the ecological environment and human health. Selective catalytic reduction (SCR) technology is widely employed for the removal of nitrogen oxides, with copper-cerium-based bimetallic catalysts and their derivatives demonstrating excellent catalytic efficiency in SCR reactions, primarily due to the significant synergistic effect between copper and cerium. This paper summarizes the main factors affecting the catalytic performance of Cu-Ce-based bimetallic catalysts and their derivatives in the selective catalytic reduction of ammonia and carbon monoxide. Key considerations include various preparation methods, doping of active components, and the effects of loading catalysts on different supports. This paper also analyzes the influence of surface oxygen vacancies, redox capacity, acidity, and specific surface area on catalytic performance. Additionally, the anti-poisoning performance and reaction mechanisms of the catalysts are discussed. Finally, the paper proposes strategies for designing high-activity and high-stability catalysts, considering the development prospects and challenges of Cu-Ce-based bimetallic catalysts and their derivatives, with the aim of providing theoretical guidance for optimizing Cu-Ce-based catalysts and promoting their industrial applications.

Ultrasound-Responsive Lipid Nanoplatform with Nitric Oxide and Carbon Monoxide Release for Cancer Sono-Gaso-Therapy.

Local gas therapy is emerging as a potential cancer treatment approach due to its specificity as gas-containing molecules can be packed into a nanodelivery system to release the corresponding gaseous molecules around the tumor site upon a suitable stimulus. Single-gas therapy has been reported, while synergistic dual-gas therapy has rarely been reported. Herein, we report a dual-gas-containing nanoplatform for synergistic cancer gasotherapy upon ultrasound irradiation. First, a robust ultrasound-responsive lipid-coated nanosystem was prepared with suitable particle size and characteristics. A low-intensity ultrasound (1.25 W/cm2) was found to simultaneously modulate carbon monoxide (CO) and nitric oxide (NO) release from the nanosystem in media and CT26 colon cancer cells for efficient therapeutic effect. The intracellular release promoted the overgeneration of reactive oxygen species (ROS) and triggered cancer cell apoptosis synergistically. The in vivo test demonstrated that the optimal dual-gas-containing formulation efficiently inhibited tumor growth (by ∼87%) at relatively low doses upon ultrasound irradiation (1.25 W/cm2, 5 min). This therapeutic efficacy shows that the current responsive lipid-coated delivery system has potential for ultrasound-triggered dual-gas therapy of both superficially and deeply seated cancers.

Revealing the differences in CO oxidation activity of Fe-CeO2, Fe2O3, and CeO2 using operando CO2-DRIFTS-MS: Carbonate species and desorption process

The carbonate on the catalyst surface is the key factor limiting carbon monoxide (CO) oxidation activity. However, the relationship between different carbonate species and surface oxygen species is not clear. In this paper, Fe-CeO2, Fe2O3, and CeO2 catalysts prepared by aerosol method are selected as the research target, and operando DRIFTS-MS is used as the main characterization method. Fe-CeO2 has good redox properties resulting in the best CO oxidation activity (350°C) and CO2 selectivity (98 %). Operando DRIFTS-MS results indicate that surface M=O species play a crucial role in the catalyst's activity, demonstrating the ability to react with CO at low temperatures. Notably, a high concentration of M=O facilitates the formation of monodentate carbonate (vas(CO32−)) (vas(CO32−) decomposes at 100°C). With increasing temperature, CeO and M-O-Ce also react with CO and produce M-Ov-Ce (oxygen vacancy). CO adsorption on M2+-O22− or M sites to form vas(OCO) or vs(OCO). The decomposition temperature of vs(OCO) exceeds that of vas(CO32−) significantly, and its presence serves as the crucial step in the oxidation of CO. The above conclusions reveal the relationship between surface carbonate and oxygen, and provide a theoretical basis for regulating the surface structure of catalysts.

Homogeneous Catalysts of RedOx Processes Based on Heteropolyacid Solutions. VI: Developing a Process for Low-Temperature Oxidation of CO with Oxygen

Research on the development of a homogeneous process for low-temperature oxidation of carbon monoxide in the presence of a “platinum group metal + vanadium-containing heteropolyacid (HPA)” catalytic system has been presented. The optimal reaction conditions, ensuring the maximum rate of CO oxidation to CO2, have been determined; for this reaction the kinetic features have been established, and its mechanism has been proposed. It has been shown that homogeneous systems based on PdII complex exhibit high activity and productivity, but have low stability and operate only at pH below 1,5. The stability of the catalyst can be increased by simultaneous introduction of σ- and π-donor ligands into the system; however, it is more effective to use the PtIV complex in the presence of catalytic amounts of palladium salt at a ratio of 100/1. The transition from HPA solutions with a low content of vanadium atoms (H7PMo8V4O40) to solutions of modified compositions (H10P3Mo18V7O84) ensures an increase in the activity and productivity of the system, with the kinetics of CO oxidation being maintained. The combined homogeneous catalyst PtIV + PdII + H10P3Mo18V7O84 remains stable during multi-cycle use without reducing activity, operates without an induction period and can be used at pH range of 1,7–2,0, which simplifies the process equipment.

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.

STUDYING THE EFFECT OF MAGNETIC FLUX ON DIESEL FUEL LINE ON SOME PERFORMANCE AND EMISSION OF DIESEL ENGINE

This study aimed to investigation was carried out to evaluate the performance and product emission of four cylinder 4- stroke water cooled direct injection (DI) diesel engine fueled by permanent magnet exposed diesel fuel compared with diesel fuel (DF). Three levels of magnet field intensity were used including Diesel fuel exposer to 3000 Gauss (DG3), Diesel fuel exposer to 5000 Gauss (DG5) and Diesel fuel exposer to 9000 Gauss (DG9) fuel respectively. Permanent magnetic device was employed and installed on fuel line before interring high pressure fuel injection pump . The engine run at constant speed 1500rpm(revolution per minute) and loaded by two levels 4.5 kW and 9 kW represented as L1and L2 respectively. Results obtained showed that fuel DG5 registered an increased in thermal efficiency(TE) about 20.09% at load L1 compared with DF. Maximum reduction in brake specific fuel consumption (bsfc) about 12.12%, when using DG5 fuel at load 1 compared to DF fuel. All exhaust emission Unburned Hydrocarbon (UHC), Carbon Monoxide (CO), Carbon Dioxide (CO2),Particular Maters (PM), and Nitrogen Oxides (NOx) are decreased when diesel fuel treated with different magnetic intensities 3000,5000 and 9000 Gauss. Compared with conventional diesel fuel. Maximum reduction in PM,HC,NOx,CO2,and CO about 16.56-27.08%, 3.89–64.26%, 4.79–7.91%, 4.05-5.71and 11.46-53.48% respectively. CO2 emission was increased by 1.65-4.28 at DG5 with L1 and L2 respectively due to the operating conditions.

Advanced hybrid neural network techniques for minimizing gas turbine emissions

Purpose Emissions have significant environmental impacts. Hence, minimizing emissions is essential. This study aims to use a hybrid neural network model to predict carbon monoxide (CO) and nitrogen oxide (NOx) emissions from gas turbines (GTs) to enhance emission prediction for GTs in predictive emissions monitoring systems (PEMS). Design/methodology/approach The hybrid model architecture combines convolutional neural networks (CNN) and bidirectional long-short-term memory (Bi-LSTM) networks called CNN-BiLSTM with modified extrinsic attention regression. Over five years, data from a GT power plant was uploaded to Google Colab, split into training and testing sets (80:20), and evaluated using test matrices. The model’s performance was benchmarked against state-of-the-art emissions prediction methodologies. Findings The model showed promising results for GT CO and NOx emissions. CO predictions had a slight underestimation bias of −0.01, with root mean-squared error (RMSE) of 0.064, mean absolute error (MAE) of 0.04 and R2 of 0.82. NOx predictions had an RMSE of 0.051, MAE of 0.036, R2 of 0.887 and a slight overestimation bias of +0.01. Research limitations/implications While the model demonstrates relative accuracy in CO emission predictions, there is potential for further improvement in future research. Practical implications Implementing the model in real-time PEMS and establishing a continuous feedback loop will ensure accuracy in real-world applications, enhance GT functioning and reduce emissions, fuel consumption and running costs. Social implications Accurate GT emissions predictions support stricter emission standards, promote sustainable development goals and ensure a healthier societal environment. Originality/value This paper presents a novel approach that integrates CNN and Bi-LSTM networks. It considers both spatial and temporal data to mitigate previous prediction shortcomings.

Atmospheric Trace Gas Oxidizers Contribute to Soil Carbon Fixation Driven by Key Soil Conditions in Terrestrial Ecosystems.

Microbial oxidizers of trace gases such as hydrogen (H2) and carbon monoxide (CO) are widely distributed in soil microbial communities and play a vital role in modulating biogeochemical cycles. However, the contribution of trace gas oxidizers to soil carbon fixation and the driving environmental factors remain unclear, especially on large scales. Here, we utilized biogeochemical and genome-resolved metagenomic profiling, assisted by machine learning analysis, to estimate the contributions of trace gas oxidizers to soil carbon fixation and to predict the key environmental factors driving this process in soils from five distinct ecosystems. The results showed that phylogenetically and physiologically diverse H2 and CO oxidizers and chemosynthetic carbon-fixing microbes are present in the soil in different terrestrial ecosystems. The large-scale variations in soil carbon fixation were highly positively correlated with both the abundance and the activity of H2 and CO oxidizers (p < 0.05-0.001). Furthermore, soil pH and moisture-induced shifts in the abundance of H2 and CO oxidizers partially explained the variation in soil carbon fixation (55%). The contributions of trace gas oxidizers to soil carbon fixation in the different terrestrial ecosystems were estimated to range from 1.1% to 35.0%. The estimated rate of trace gas carbon fixation varied from 0.04 to 1.56 mg kg-1 d-1. These findings reveal that atmospheric trace gas oxidizers may contribute to soil carbon fixation driven by key soil environmental factors, highlighting the non-negligible contribution of these microbes to terrestrial carbon cycling.

Comparative Analysis of Performance and Exhaust Emissions from Jet A1 Blends with Various Aviation Biofuels

The aviation industry is a significant contributor to greenhouse gas emissions. Given the growing demand for air travel and the unsustainable use of fossil fuels, it is crucial to develop and commercialize renewable fuels to reduce these emissions. Conventional jet fuels like Jet A1 release harmful pollutants such as carbon monoxide (CO) and nitrogen oxides (NOx) into the atmosphere. In contrast, biofuels offer a renewable, biodegradable, and non-toxic alternative that emits fewer pollutants, excluding NOx, and is easier to treat than fossil fuels. Due to their eco-friendly characteristics, biofuels have garnered attention in recent years. This study focuses on producing biofuels from jatropha oil and waste cooking oil. Jatropha oil, aside from its medicinal benefits such as antimicrobial and anticancer properties, can be effectively used in industrial applications, particularly for biofuel production. The production of biofuels from jatropha and waste cooking oil is of growing interest due to their environmental and economic benefits. The study investigates the production of these biofuels using appropriate catalysts under controlled experimental conditions, followed by blending the biofuels with Jet A1 fuel to achieve similar engine performance while mitigating the environmental impact of greenhouse gases from petroleum-based fuels.

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.

Optimization of operational parameters of marine methanol dual-fuel engine based on RSM-MOPSO

Methanol and natural gas, as green fuels for environmental protection, have shown great potential in the field of maritime transportation. This study explores how the methanol energy fraction (MEF), exhaust gas recirculation (EGR), excess air ratio (λ), and engine injection timing (EIT) influence combustion and emission traits in marine dual-fuel (DF) engine. Initially, a DF engine model was formulated through experiments using CONVERGE software, while the CHEMKIN program devised a chemical mechanism involving 100 compounds and 512 reactions. The response surface methodology (RSM) was subsequently utilized to design the experiment and develop the regression model. The improved multi-objective particle swarm optimization (MOPSO) algorithm was applied to optimize three critical variables: brake thermal efficiency (BTE), carbon monoxide (CO), and nitrogen oxide (NOx) emissions. Ultimately, feature-optimized scenarios from the Pareto front were chosen for comparative evaluation to derive the optimal configuration. The results show that when the decision variables MEF, EGR, λ and EIT are 22.33 %, 10 %, 1.81 and 11°CA BTDC respectively, there is a better trade-off between the three target variables. Compared with the original case, the change of ITE, NOx and CO emissions in the optimal case are +0.97 %, −39.53 % and −14.51 %, respectively. Overall, based on the intelligent optimization approach, the rational selection of DF engine parameters improved the ITE and most NOx and CO emissions were effectively suppressed.

Combustion of liquid hydrocarbon fuels sprayed into gas generation chamber with superheated steam as low emission technology for energy production

Experimental and numerical studies were conducted to scientifically validate the Steam Injection Method with Gas Generation chamber (SIMGG) as a low-emission combustion technology for energy production in low and medium power boilers using different types of fuels. For the first time, a fully functional prototype of a burner implementing SIMGG was tested under the conditions of a standard low-power boiler installation, and combustion characteristics of fuels with various physical properties (diesel fuel and a mixture of used automotive oils) were obtained under different operating parameters. The results of the studies show that using SIMGG reduces carbon monoxide (CO) and nitrogen oxides (NOx) emissions by up to half or more under closed-combustion conditions for various fuels. The lowest total emissions of CO and NOx are achieved at an air excess coefficient of 1.2 and a steam-to-fuel ratio of greater than 0.66.

Electronic communications between active sites on individual metallic nanoparticles in catalysis

Catalytic activity of metal particles is reported to originate from the appearance of nonmetallic states, but conductive metallic particles, as an electron reservoir, should render electron delivery between reactants more favorably so as to have higher activity. We present that metallic rhodium particle catalysts are highly active in the low-temperature oxidation of carbon monoxide, whereas nonmetallic rhodium clusters or monoatoms on alumina remain catalytically inert. Experimental and theoretical results evidence the presence of electronic communications in between vertex atom active sites of individual metallic particles in the reaction. The electronic communications dramatically lower apparent activation energies via coupling two electrochemical-like half-reactions occurring on different active sites, which enable the metallic particles to show turnover frequencies at least four orders of magnitude higher than the nonmetallic clusters or monoatoms. Similar results are found for other metallic particle catalysts, implying the importance of electronic communications between active sites in heterogeneous catalysis.

Enhanced carbon monoxide poisoning resistance of Pd/BEA by integrating with CeO2 for low temperature NO adsorption: The role of CeO2 on oxidizing carbon monoxide to CO32−

Passive NOx adsorption (PNA) represents a promising technology for controlling NOx emissions during cold starts. However, Pd/zeolite catalysts, the latest generation of PNA materials, suffer from serious deactivation under CO concentrations, owing to the CO induced aggregation of highly dispersed Pd sites to PdO particles. In this work, we found that the resistance to CO poisoning of Pd/BEA can be enhanced by integrating with CeO2 through physical mixing. The resulting CeO2 + Pd/BEA composite catalyst demonstrated a notably higher NOx storage capacity (with a NOx/Pd ratio of 1.3) compared to Pd/BEA (0.8). This improvement can be attributed to the interaction between CeO2 and the BEA support, which promoted the formation of nitrates on CeO2 during NO adsorption at 80 °C. More importantly, CeO2 effectively shielded Pd2+ ions from reduction by CO, with 88 % of Pd2+ ions remaining after CO exposure, significantly outperforming Pd/BEA, which retained only 66 %. Spectra characterization and DFT results indicate that the defects in CeO2 strongly trapped CO (−0.973 eV), and the oxidation of trapped CO to CO32− by adsorbed oxygen (Oads) was exothermic (−1.35 eV), which reduced the exposure of Pd2+ ions to CO and inhibited the reduction and agglomeration of Pd2+ ions. While the composite sample still exhibited a slight reduction in NOx storage capacity after CO poisoning, with the NOx/Pd ratio decreasing from 1.3 to 0.9. The DFT simulation results indicate that the Ce-Oads bonds in CeO2 are weakened during the decomposition of the CO32− intermediate. This weakening could potentially facilitate the release of Oads, thereby reducing the Oads content as evidenced by spectral evidence. The decrease of Oads diminished nitrate formation on the CeO2 component in composite sample, resulting in the decline of NOx storage capacity after CO poisoning.

Al‐Decorated C20 Fullerene as a Promising Noble Metal‐Free Catalyst for CO Oxidation: A DFT Study

AbstractTo remove the toxic carbon monoxide (CO) gas from the environment, recently, researchers have taken great interest in single‐atom catalysts (SACs). In this study, we investigated various reaction pathways and barrier energies for the CO oxidation process onto Al‐decorated C20 fullerene (Al@C20) employing density functional theory (DFT). The outcomes validate that Al decoration on C20 is energetically stable while the corresponding electronic properties show that the Al atom acts as the reactive site for catalytic activity. The bond distances and larger negative adsorption energies (−0.65 and −2.53 eV) evince that CO and O2 species adsorbed strongly to the Al atom. For the oxidation of CO, two popular mechanisms are examined: Eley Rideal (ER) and Langmuir Hinshelwood (LH). The assessment of energy barriers discloses that the CO oxidation reaction progresses via the LH mechanism. Additionally, the CO + O* → CO2 reaction proceeds very quickly onto the Al@C20 catalyst, with a very small energy barrier (0.13 eV), indicating the excellent catalytic reactivity of the studied catalyst. These results propose that the designed catalyst can be valuable in the progress of novel noble metal‐free catalysts for harmful CO elimination from the environment.

Synergistic removal of NO and CO in industrial waste gas by Fe-modified Cu/TiO2 catalysts: The synergistic effect of metal oxides interaction

NH3-based selective catalytic reduction (NH3-SCR) combined with carbon monoxide (CO) catalytic oxidation is a productive way to synergistically remove nitrogen oxides (NOx) and CO from industrial waste gas. Catalyst is the undoubtedly centerpiece of the synergistic removal technology, which has aroused tremendous attention. Herein, in this investigation a variety of Cu/TiO2 catalysts modified by various metal oxides were prepared by impregnation method, and the excellent synergistic removal performance of Fe-modified Cu/TiO2 catalyst was observed. The Cu/TiO2 catalyst with a 7 wt% Fe doping amount exhibited the highest NO and CO removal efficiency (86 % for NO at 300 °C and over 98 % for CO from 300 ∼ 400 °C). Through a series of characterization techniques, it was discovered that Cu and Fe oxides interacted to evenly distribute them throughout the surface of TiO2 support, resulting in smaller particle size and abundant variable valence species (Cu+/Cu2+ and Fe2+/Fe3+) to enhance the redox performance of the catalysts. Moreover, the creation of additional surface chemisorbed oxygen, the adsorption of NO and CO, and the improvement of surface acidity were all facilitated by the electron transfer between various Cu and Fe species. In addition, in-situ diffuse reflectance infrared transform spectroscopy (in situ DRIFTS) results revealed the interaction between NH3-SCR and CO oxidation. This study proposes a viable approach to develop efficient catalysts for the synergistic removal of NO and CO in industrial applications.

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.

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.