Major Source Of Carbon Monoxide Research Articles

To optimized various parameters of Hopcalite catalysts in the synthetic processes for low temperature CO oxidation

Carbon monoxide (CO) is very poisonous gasses present in the atmosphere and lower temperature complete oxidation of CO is very important processes for all life support. The automobile vehicles exhaust is one of the major sources of CO produced into the environment. The application of catalytic converter in automobile vehicles reduces the toxic gasses emission. There are lots of catalysts used in the catalytic converter for CO oxidation purposes among these catalysts the Hopcalite (CuMnOx) is one of the oldest and best-known catalysts for low temperature CO oxidation. The hopcalite catalyst is prepared by the co-precipitation method and preparation parameters like magnetic shaker shaking speed, shaking time, shaking temperature and pH has an influence on the activity of resultant catalysts. The activity of catalyst was measured in reactive calcinations (RC) conditions at the presence of (1.5% CO) and air. The reaction temperature was increased from room temperature to higher temperature at which the total oxidation of CO was achieved. The characterizations of catalysts are done by several techniques like XRD, FTIR, BET and SEM-EDX. These results are interpreted in terms of structure the active catalyst. The reusability of CuMnOx catalyst was also tested and also found that this catalyst does not show any high level of significant change in its catalytic performances even after reuses.

Synthesis and applications of titanium oxide catalysts for lower temperature CO oxidation

Carbon monoxide (CO) is one of the very poisonous gasses and major sources of CO produced into the environment by the automobile vehicles exhaust. There are various types of catalysts have been used in the catalytic converter for CO oxidation. The titanium dioxide (TiO2) is one of the best transitional metal oxides catalysts for lower temperature CO oxidation. A small amount of TiO2 was deposited on the mesoporous Al2O3 using atomic layer deposition and subsequent oxidation at the different temperatures. The lightly reduced support improves the high catalytic activity of the adparticles, a strongly reduced one quenches the CO oxidation. The quenching is due to thermally activated diffusion of Ti3+ interstitials from the bulk to the surface where they deplete the oxygen adsorbed onto the clusters by the formation of TiOx (x ​≃ ​2) structures. The additions of promoters and support in titanium oxide catalysts improved their performances and reduced their stability. The bulk reduction state of TiO2 strongly affects the catalytic activity of supported metal clusters in the chemical reactions between oxygen and other molecules. The certain attention has been paid on the recovery of TiO2 catalysts from reaction systems and their reuse for various times without losses of catalytic activity in CO oxidation. This investigation will shown scientific basis for potential design of Ti-oxide nano-particle catalysts for lower temperature CO oxidation.

Non-Fire Related Carbon Monoxide Poisoning in Sichuan, China: A 9-Year Study (2008-2016)

Carbon monoxide (CO) poisoning is one of the most important intoxications in the modern world. This study aimed to identify the characteristics of CO poisoning deaths in Sichuan province in the west of China. Data on fatal non-fire-related carbon monoxide poisoning in Sichuan from 2008 to 2016 were obtained from the Department of Forensic Analytical Toxicology of Sichuan University and were analyzed by the month and year of registration of death, sex, age group, manner of death, source of CO, and location of CO exposure. Comparing with the previous studies carried out in Wuhan and Shanghai to identify the regional differences of CO poisoning in China. A total of 165 non-fire related CO poisoning cases including 237 victims were recorded. Over 90% of the victims died from accidental poisoning. Non-fire related CO poisoning occurred more frequently in winter months and was most prevalent in individuals aged between 18 and 60 yr old. Showering gas accident and coal or charcoal burning was found to be the major source of CO in accident and in suicide cases, respectively. Furthermore, significant regional differences of CO poisoning have been detected in the manner of death and the source of CO. These findings will be valuable in the targeted prevention of non-fire related CO poisoning in China.

Impact of CO generation during the melting process on carbon concentration in Czochralski silicon

A new carbon contamination model in which carbon monoxide (CO) generated by the chemical reaction between H2O and graphite components during the heating stage can react with the solid-state silicon feedstock was proposed. The influence of CO on carbon concentration during the heating stage in a laboratory-scale Czochralski furnace was investigated using a quadrupole mass spectrometer. A strong peak of CO and H2O partial pressure was observed before the silicon feedstock began to melt. We believe that the purge tube is a major source of CO during the heating stage because carbon contamination of the order of 1016 occurred in the silicon melt by CO generated from the purge tube. Furthermore, we discussed the impact of the SiC film formed on the surface of the silicon feedstock on carbon contamination.

Scaling relationship between CO pollution and population size over major US metropolitan statistical areas

As the world’s population is projected to reach 9.7 billion by 2050, large and small cities will continue to expand. There are few studies investigating how the size of cities affects air pollution. Carbon monoxide (CO), a precursor of ozone and a by-product of incomplete combustion, is a common air pollutant. The major sources of CO in the US urban areas are motor vehicles. Here we examined the scaling relation of CO concentrations over major US metropolitan statistical areas (MSAs) using Measurement Of Pollution in The Troposphere (MOPITT) surface CO retrievals and National Emissions Inventory (NEI) data. We found significant power-law scaling relationships between CO and population (r2 of 0.30 for MOPITT average CO concentration and r2 of 0.71 for NEI total CO emission). We found decreasing CO trends from 2000 to 2015 using MOPITT and EPA CO ground measurements. Sublinear scaling relationships (scaling coefficient β < 1) suggest that larger MSAs are more combustion-efficient in terms of CO emissions. We found a weaker scaling relation and smaller scaling coefficient from MOPITT CO concentrations than from NEI total CO emission data. This pattern may be attributed to the differences between the two CO datasets: annual average of monthly MOPITT CO concentration at 1° by 1° spatial resolution versus the NEI annual CO emissions compiled from emission inventories and estimated from mobile source emissions models. Future research is needed to investigate the capability of using satellite observations to study scaling relations between air pollutants and population.

Unintentional carbon monoxide poisoning to the occupant of motor car by exhaust gases emitted by stranded traffic vehicles and the motor car itself

Incompletely burnt organic material is the major source of carbon monoxide in the environment. The hazardous nature of Carbon monoxide (CO) is mainly due to it being odourless, colourless, non-irritating, and tasteless and its omnipresent nature. It is also termed as a “silent killer” as it lacks the sensory warning properties. In the present case, a 30-year-old male was found dead in his car which was stuck in a pool of water along with many other vehicles stranded in a narrow lane following heavy rains. Autopsy features of CO poisoning were evident on examination. Chemical analysis report was positive for carboxyhemoglobin and alcohol. Fatal concentrations of CO gas are known to occur inside the automobile cabins due to defective exhaust systems. Alcohol impairs the reaction time and sensibility towards the signs of CO toxicity thereby reducing chances of survival. Awareness regarding dangers of CO poisoning, regular maintenance of vehicle and use of CO detectors are some of the key measures to avoid such fatalities. This case highlights the dangerous nature of carbon monoxide and fatal outcome of its exposure in an atmosphere with heavy concentration of exhaust gases and an enclosed space like a car in addition to the incapacitating effect of alcohol.

Carbon monoxide poisoning as a cause of death and differential diagnosis in the forensic practice: A retrospective study, 2000–2010

This study presents the epidemiology and the postmortem forensic aspects in cases with a carboxihemoglobin (COHb) analysis, from autopsies performed at the Forensic Pathology Department of the Centre Branch of the National Institute of Legal Medicine and Forensic Sciences of Portugal. Between January 2000 and December 2010, 69 COHb analyses were requested in our institution. In approximately 70% of the situations, circumstantial information included a Carbon Monoxide (CO) source at the death scene. More than half of the cases presented thermal lesions, cherry-red lividity, and cherry-red blood and viscera coloration were found in, approximately, 30% of the cases. Fourteen cases were recorded as CO poisonings. The highest number of poisonings occurred in 2000, with most of the cases in winter (53.8%), in 51–60 years-old male individuals. 69.2% of the poisonings were accidental and the remainder were suicides, being fires the most frequent sources of CO (38.5%). Cherry-red lividity was present in 61.5% of the cases, and all of them presented cherry-red blood and viscera coloration. Older individuals and those with thermal lesions presented lower COHb levels, and politrauma was the most frequent cause of death among the negative cases. It is possible to conclude that the forensic aspects of CO poisonings interact in a complex way, and differential diagnosis is not straightforward. This study also emphasizes the role played by public prevention campaigns and improvement of heating appliances in reducing the number of accidental CO poisonings, and the importance of preventing urban and forest fires, the major source of CO among us.

Evaluation of 2001 springtime CO transport overWest Africa using MOPITT CO measurements assimilated in a global chemistry transport model

The global chemistry and transport model MOCAGE (Modèle de Chimie Atmosphèrique à Grande Echelle) is used to investigate the contribution of transport to the carbon monoxide (CO) distribution over West Africa during spring 2001. It is constrained with the CO profiles provided by the Measurements Of Pollution In The Troposphere (MOPITT) instrument through a sequential assimilation technique based on a suboptimal Kalman filter. The improvement of troposphericCOdistribution fromMOCAGEis evaluated by comparing the model results (with and without assimilation) with the MOPITT CO concentrations observed during the analysed period (between 2001 March 15 to 2001 April 30), and also with independent in situ CMDL and TRACE-P observations. The initial overestimation in high CO emissions areas (Africa, SE Asia andNWcoast of South America) is considerably reduced by using the MOPITT CO assimilation. We analysed the assimilated CO for a period of three successive 15 d periods in terms of average fields overWest Africa and contributions to the CO budget of transport and chemical sources. It is found that the horizontal and vertical CO distributions are strongly dependent on the characteristics of the large-scale flows during spring, marked by the onset of the low-level southerly monsoon flow and the gradual increase of the well-known African and tropical easterly jets at middle and upper levels, respectively. Total transport by the mean flow (horizontal plus vertical advection) is important in the CO budget since it mostly compensates the local sink or source generated by chemical reactions and small-scale processes. The major source of CO is concentrated in the lower troposphere (1000–800 hPa) mainly due to convergent low-level flow advecting CO from surrounding regions and surface emissions (biomass burning). Vertical transport removes 70% of this low-level COand redistributes it in the middle troposphere (800–400 hPa) where chemical reactions and horizontal exports contribute to the loss of CO. A lesser proportion is transported upwards into upper troposphere, and then horizontally, out of the considered domain.

Personal carbon monoxide exposure in Helsinki, Finland

Abstract Personal exposure concentrations of carbon monoxide (CO) were measured for the adult urban population of Helsinki, Finland, as part of the multi-centre European EXPOLIS study. The arithmetic mean of the 48 h average personal CO exposure concentration was 1.3 mg m−3 for participants not exposed to environmental tobacco smoke (ETS) and 1.6 mg m−3 for those exposed to ETS at any time and in any microenvironment. The maximum 8 and 1 h exposure values were 2.0 and 2.6 mg m−3, and 4.3 and 5.7 mg m−3, respectively. As tobacco smoke is one of the major sources of CO, therefore the personal mean exposures of ETS participants were higher than the non-ETS participants for all averaging times. The long- and short-term personal exposures were higher in winter than in summer for all participants. In order to analyse in more detail the correlation between the time-activity patterns and exposure levels, cluster analysis was performed using 24 h personal exposure profiles of 1 h moving averages. The results showed clearly that the major source of CO for non-ETS exposed participants are traffic emissions. The majority of the diurnal exposure profiles showed two notable exposure peaks corresponding to the morning and evening traffic rush hours. The time spent in street traffic was the most relevant factor for describing the short-term personal exposures. The more time was spent commuting by car the higher were the exposures. The long-term exposure levels were linked both to the time spent commuting and home location. People living in low-traffic suburban areas and working in downtown spent more time commuting and ended up experiencing similar long-term exposure levels than people who lived in heavy-traffic downtown areas, but spent little time commuting. For ETS exposed participants the personal exposure profiles were dominated by both tobacco smoke and traffic emissions.

Impacts of biomass burning on tropospheric CO, NOx, and O3

This study utilizes the National Oceanic and Atmospheric Administration Geophysical Fluid Dynamics Laboratory three‐dimensional global chemical transport model to quantify the impacts of biomass burning on tropospheric concentrations of carbon monoxide (CO), nitrogen oxides (NOx), and ozone (O3). We construct updated global sources that emit 748 Tg CO/yr and 7.8 Tg N/yr in the surface layer. Both sources include six types of biomass: forest, savanna, fuelwood, agricultural residues, domestic crop residues (burned in the home for cooking and/or heating), and dried animal waste. Timing for the burning of forest, savanna, and agricultural residues is based upon regional cultural use of fire, vegetation type, local climate, and information gathered from satellite observations, while emissions from the burning of fuelwood, domestic crop residues, and dried animal waste are constant throughout the year. Based on agreement with observations, particularly of CO, we conclude that the collective uncertainty in our biomass burning sources is much less than the factor of two suggested by previous estimates of biomass burned in the tropics annually. Overall, biomass burning is a major source of CO and NOx in the northern high latitudes during the summer and fall and in the tropics throughout most of the year. While it contributes more than 50% of both the NOx and CO in the boundary layer over major source regions, it has a much larger global impact on the CO distribution in comparison to either NOx or O3, contributing 15 to 30% of the entire tropospheric CO background. The only significant biomass burning contribution to NOx at 500 mbar, due to the short lifetime of NOx in the lower troposphere, is a plume occurring July through October in the Southern Hemisphere subtropical free troposphere, stretching from South America to the western Pacific. The largest impacts on O3 are limited to those regions where NOx impacts are large as well. Near the surface, biomass burning indirectly contributes less than half of the total O3 concentrations over major tropical source regions, up to 15% throughout the year in the tropics, and 10 to 20% throughout the Southern Hemisphere during September through November. At 500 mbar, the largest contribution to O3 (20–30%) is correlated with the NOx plume during July through November. Biomass burning contributes less than 15% of either NOx or O3 in the upper troposphere.

An unusual case of carbon monoxide poisoning.

Carbon monoxide, a gas originating from incomplete combustion of carbon-based fuels, is an important cause of human deaths. In this paper, we describe an unusual carbon monoxide poisoning in a dwelling without obvious sources of combustion gases, for which two adults had to be treated in a hyperbaric chamber. Carbon monoxide readings were taken in the house and in the neighboring homes. Methane gas and nitrogen oxide levels were also monitored in the house air. Soil samples were collected around the house and tested for hydrocarbon residues. The investigation revealed the presence of a pocket of carbon monoxide under the foundation of the house. The first readings revealed carbon monoxide levels of 500 ppm in the basement. The contamination lasted for a week. The investigation indicated that the probable source of contamination was the use of explosives at a nearby rain sewer construction site. The use of explosives in a residential area can constitute a major source of carbon monoxide for the neighboring populations. This must be investigated, and public health authorities, primary-care physicians, governmental authorities, and users and manufacturers of explosives must be made aware of this problem.

Sources of atmospheric carbon monoxide

Carbon monoxide (CO) is one of the main reactive trace gases in the earth's atmosphere: it influences both the atmospheric chemistry and the climate. In order to evaluate the atmospheric budget of CO, knowledge of the emission rates from, and the, geographic distribution of, the individual sources are required. CO is released into the atmosphere naturally and anthropogenically: at present, the emission rates from these two categories of sources are comparable. However, the rates of emission from man-made sources have been increasing steadily since industrialisation began, and are expected to continue growing with changes in population and economy. Although the major sources of CO are known, estimates for their emission rates are still uncertain. Experimental data are available only for a limited number of locations, and more measurements in representative regions world-wide are required in order to evaluate the CO global budget more accurately.