Distribution Of Carbon Monoxide Concentration Research Articles

Analysis of carbon monoxide (CO) distribution in Pekanbaru City and its surroundings due to forest fires

One of the pollutants produced from forest fire is carbon monoxide (CO). The resulting CO pollutants can interfere with human health and even lead to death. In Riau Province, high forest fire was occurred in 2015, while low forest fire was occurred in 2017. An indicator that can be seen as a determinant of high or low forest fires is hotspots. The research was conducted with the aim of comparing the distribution of CO pollutants in 2015 and 2017, as well as find out the correlation between the number of hotspots and the CO concentration. The data used was obtained from the Giovanni website and FIRMS MODAPS NASA. The results showed there was a significant difference in the distribution of CO concentration in 2015 and 2017. In 2015, CO concentrations were higher than 2017. The highest value of CO concentration in 2015 was 226.949 g/m3 while the highest CO concentration value in 2017 was 109.966 g/m3. The relationship between the number of hotspots and the CO concentration values in 2015 and 2017 in Pekanbaru City and its surroundings are -0.585 and -0.602, respectively. The CO concentration in Pekanbaru is affected by surrounding area and the number of vehicles.

Line source dispersion and spatial distribution of carbon monoxide concentration on Daan Mogot Street, Tangerang City, Jabodetabek Metropolitan Area

Air pollution is the most common problem in urban areas. Emissions from transport are hypothesized to be the main cause of this pollution. Therefore, studies on air pollution on a local scale must be carried out, especially on pollutants related to emissions from transportation, carbon monoxide. This study aims to provide an up-to-date study regarding the specific conditions of Carbon Monoxide concentration in the Daan Mogot Street area. This research uses the Gaussian Line Source and Geographic Information System (GIS) methods. This research shows that carbon monoxide concentrations around Daan Mogot Street ranged from 195.56-1482.50 μg/m3. This research findings are expected to anticipate the increase in the concentration of carbon monoxide in the research area, affecting the sustainability of people around the research area.

Numerical analysis of reasons for the CO distribution in an opposite-wall-firing furnace

In practical operations, the carbon monoxide (CO) distribution in an opposite-wall-firing furnace (OWFF) is characterized by a high concentration near the side walls and a low concentration in the center, accompanied by a series of combustion-related issues. To find the reasons for the CO distribution, a numerical study was conducted on a 660 MWe OWFF. The CO concentration profiles, distribution coefficients of coal and air, mixing coefficients, and the aerodynamic characteristics were extracted for analysis. The CO distribution within the furnace greatly depends on the mixing of coal and air. A mismatch between the aerodynamic behaviors of coal and air causes the non-uniform distribution of CO. Taking into consideration that distinctive flow patterns exist within the different regions, the formation mechanisms of the CO distribution can be divided into two components: (1) In the burner region, the collision of opposite flows leads to the migration of gas and particles toward the side wall which, together with the vortexes formed at furnace corners, is responsible for unburned particles concentrated and oxygenized from the furnace center to the side wall. Thus, high CO concentrations appear in these areas. (2) As the over-fire air (OFA) jet is injected into the furnace, it occupies the central region of furnace and pushes the gas from the burner region outward to the side wall, which is disadvantageous for the mixing effect in the side wall region. As a consequence, a U-shaped distribution of CO concentration is formed. Our results contribute to a theoretical basis for facilitating the control of variation in CO concentration within the furnace.

Investigation of CO emissions on school areas based on Caline-4

The school located near the city’s main transportation line at first profitable for the school because the location is easy to reach. From the location of the school is considered strategic but not fit with convenience of studying in school, the problem arises that the location close to the main road tends to have a higher level of air pollution and leads to impact the students at school. The purpose of this research is to know the level of carbon monoxide at the school area uses modelling CALINE-4 and the pattern of distribution of emission CO at school area with CALINE-4. This research was done in three locations for three days namely MAN 2 Model Makassar, SMA Negeri 11 Makassar and SMP Negeri 4 Makassar. Analysis of the distribution of Carbon Monoxide CO emissions using Caline 4. The largest result of Carbon Monoxide (CO) pollutants in MAN 2 Model Makassar at 05:00 pm, namely the b receptor is beside the school at as much as 9 ppm. In SMAN 11 Makassar, the biggest carbon monoxide (CO) pollutant was at 07:00 pm the two receptors in front of the school as much as 2.2 ppm. And in SMPN 4 Makassar, the biggest carbon monoxide (CO) pollutant was at 06:00 am the receptor in front of the school as much as 3.1 ppm. The pattern of distribution of CO concentration is influenced by the wind speed and wind direction affecting the pattern of the distribution of these pollutants. The faster the wind blows, the spread of pollutants is faster with a wide range.

Estimating ground-level CO concentrations across China based on the national monitoring network and MOPITT: potentially overlooked CO hotspots in the Tibetan Plateau

Abstract. Given its relatively long lifetime in the troposphere, carbon monoxide (CO) is commonly employed as a tracer for characterizing airborne pollutant distributions. The present study aims to estimate the spatiotemporal distributions of ground-level CO concentrations across China during 2013–2016. We refined the random-forest–spatiotemporal kriging (RF–STK) model to simulate the daily CO concentrations on a 0.1∘ grid based on the extensive CO monitoring data and the Measurements of Pollution in the Troposphere CO retrievals (MOPITT CO). The RF–STK model alleviated the negative effects of sampling bias and variance heterogeneity on the model training, with cross-validation R2 of 0.51 and 0.71 for predicting the daily and multiyear average CO concentrations, respectively. The national population-weighted average CO concentrations were predicted to be 0.99±0.30 mg m−3 (μ±σ) and showed decreasing trends over all regions of China at a rate of -0.021±0.004 mg m−3 yr−1. The CO pollution was more severe in North China (1.19±0.30 mg m−3), and the predicted patterns were generally consistent with MOPITT CO. The hotspots in the central Tibetan Plateau where the CO concentrations were underestimated by MOPITT CO were apparent in the RF–STK predictions. This comprehensive dataset of ground-level CO concentrations is valuable for air quality management in China.

Modeling and simulation of coal spontaneous combustion in a gob of shallow buried coal seams

The pore and fracture are the path of energy, mass and momentum transfer and conduction in the gob, determine its reasonable distribution is the basis for studying the coal spontaneous combustion hazardous area and migration law of gas products. A discrete fracture-pore model of gob in shallow buried coal seams is being proposed, which is based on the periodic pressure of the overburden, the key strata theory and the compression deformation of the broken rock mass. The model consists of a porous medium media and a discrete fracture network, and calculation equation for the porous medium and the crack width is granted. Taking the Bulianta mine as the background, the model was introduced into FLUENT to simulate the oxygen concentration field, the carbon monoxide concentration field and wind velocity field in the gob. The simulation results agreed well with the measured oxygen concentrations in the field. The spontaneous combustion danger zone and the law of carbon monoxide accumulation in gob are obtained by simulation. In the lower coal seam gob, the maximum width of the spontaneous combustion hazard zone is 108.67m, and the maximum width is 104.94m from the return air side of the gob, and its area is calculated to be 14,645 m2. In the upper coal seam gob, there is basically no spontaneous combustion danger zone that simultaneously meets wind speed and oxygen concentration. However, the oxygen concentration in most areas of the upper gob is between 8% and 18%. In order to prevent the formation of spontaneous combustion danger zone, it is necessary to take corresponding measures for the location with large surface cracks. The concentration of carbon monoxide in the lower gob is greater than the concentration of carbon monoxide in the upper gob. For upper gob, the distribution of carbon monoxide concentration is mainly affected by ground air leakage; for the lower gob, the distribution of carbon monoxide concentration is mainly affected by air leakage of working face.

Design and Numerical Simulation of a Gas Mixer

A high precision gas mixer used to mix gases of small flow rapidly and uniformly was proposed in this paper. Nine simulation schemes were proposed based on orthogonal test. There were four factors including dilute gas flow rate, the length of mixing tube, the diameter of the mixing chamber and the width of the mixing chamber in orthogonal test and each factor had three levels. The numerical simulation was carried out to explore the relationship of the flow field and the four factors and to calculate the concentration of carbon monoxide at the mixer’s outlet. The primary factor that affected the mixing effectiveness was found out by means of range analysis. The heterogeneous degree of the distribution of carbon monoxide concentration at the mixer’s outlet was smaller than 0.002 under different conditions. The results reached uniform micromixing in engineering and met the requirement of measurement and detection.

Experimental and theoretical investigation of mass transfer in a circulating fluidized bed

Catalytic oxidation of carbon monoxide over a Pt catalyst was employed as a model reaction to investigate the effect of meso-scale structure on gas-solid mass transfer in a circulating fluidized bed (CFB). Both experimental and theoretical analyses were performed to determine the conditions under which the reaction process was dominated by mass transfer. The experimental works involved the measurements of the axial distribution of carbon monoxide concentration, whereas the theoretical analyses were on the use of an Multi-Scale Mass Transfer (MSMT) model with considering effects of clusters on gas-solid transport phenomena in the CFB. The results of MSMT model show a good agreement with experimental data, suggesting that the particle clusters play an important role in the gas-solid momentum transfer and mass transfer in CFBs.

Pedestrian Exposure to Air Pollution in Cities: Modeling the Effect of Roadside Trees

The exposure of students to traffic-emitted carbon monoxide (CO) in their daily walk to school is evaluated, with a particular emphasis on the effect of trees and route choice. The study is focused on the city centre of Aveiro, in central Portugal. Time evolution of the georeferenced location of an individual is tracked with a GPS for different alternative walking routes to a school. Spatial distribution of CO concentration is simulated with a computational fluid dynamics (CFD) model. An exposure model is developed that associates the georeferenced location of the student with the computed air quality levels (at an average breathing height) for that specific grid cell. For each individual, the model calculates the instantaneous exposure at each time frame and the mean value for a given period. Results show a general benefit induced by the trees over the mean exposure of the student in each route. However, in the case of instantaneous exposure values, this is not consistent along the entire period. Also, the variability of the estimated exposure values indicates the potential error that can be committed when using a single value of air quality as a surrogate of air pollution exposure.

Distribution of CO Concentration in Two Tunnel Models Using CFD

Carbon monoxide (CO) is a primary air pollutant as an indicator of air quality released from motor vehicle combustion. A comparative study of the distributions of CO concentration with no heat source in two tunnel models open and closed at both end sides is simulated with a commercial CFD code. The tunnel models are used to investigate the CO concentration distributions at three Reynolds numbers, which are computed by the inlet velocities of 0.3, 0.6 and 1.0 ㎧. For a better tunnel design, the CFD predictive approaches are available in qualitatively studying the distributions of CO concentration. In the case of the tunnel open at both end sides in sixty seconds, the total CO concentrations are approximately twenty eight percent higher than those in the closed case.

Comparison of the distribution of carbon monoxide concentration and temperature rise in channel fires: Reduced-scale experiments

Abstract In a channel fire, the transports of the two primary hazards, heat and CO species, are dominated by different mechanisms. Experiments were conducted in a horizontal channel with dimensions of 66.0 m long × 1.5 m wide × 1.3 m high to investigate the spatial distributions of CO volume concentration and those of temperature rise. The effects of longitudinal ventilation were also considered. Both in the longitudinal direction and in the vertical direction, profiles of CO volume concentration differ with those of temperature rise. In the downstream direction, the temperature rise of smoke flow decays rapidly with increase in the distance from the fire origin, while CO volume concentration remains constant in the longitudinal direction. A larger longitudinal ventilation velocity leads to a slower decay in temperature rise along the longitudinal direction. However, longitudinal ventilation has a small influence on the longitudinal profiles of normalized CO volume concentration. As compared with temperature rise, the CO volume concentration decays more slowly with the decrease in height under the conditions without longitudinal ventilation. However, a relatively large longitudinal ventilation velocity leads to a high similarity between the vertical profile of CO volume concentration and that of temperature rise.

Two-dimensional characterization of atmospheric profile retrievals from limb sounding observations

Limb sounders measure atmospheric radiation that is dependent on atmospheric temperature and constituents that have a radial and angular distribution in Earth-centered coordinates. In order to evaluate the sensitivity of a limb retrieval to radial and angular distributions of trace gas concentrations, we perform and characterize one-dimensional (vertical) and two-dimensional (radial and angular) atmospheric profile retrievals. Our simulated atmosphere for these retrievals is a distribution of carbon monoxide (CO), which represents a plume off the coast of south-east Asia. Both the one-dimensional (1D) and two-dimensional (2D) limb retrievals are characterized by evaluating their averaging kernels and error covariances on a radial and angular grid that spans the plume. We apply this 2D characterization of a limb retrieval to a comparison of the 2D retrieval with the 1D (vertical) retrieval. By characterizing a limb retrieval in two dimensions the location of the air mass where the retrievals are most sensitive can be determined. For this test case the retrievals are most sensitive to the CO concentrations about 2° latitude in front of the tangent point locations. We find the information content for the 2D retrieval is an order of magnitude larger and the degrees of freedom is about a factor of two larger than that of the 1D retrieval primarily because the 2D retrieval can estimate angular distributions of CO concentrations. This 2D characterization allows the radial and angular resolution as well as the degrees of freedom and information content to be computed for these limb retrievals. We also use the 2D averaging kernel to develop a strategy for validation of a limb retrieval with an in situ measurement.

A Survey Technique for Determining The Representativeness of Urban Air Monitoring Stations With Respect to Carbon Monoxide

An air quality survey technique for measuring the horizontal spatial variation of carbon monoxide concentrations in urban areas is described; it was used to determine how representative an urban air monitoring station is of concentrations throughout the city. The survey technique was applied in San Jose, Calif., where 1128 samples were collected over a six-month period and were compared with the values recorded simultaneously at the urban air monitoring station. All samples were collected at “breathing height” within a 13-square-mile grid which included the downtown area as well as surrounding residential and industrial locations. Three basic sampling strategies were employed to answer specific questions about the distribution of carbon monoxide concentration: (7) walking sampling, in which samples were obtained while walking along the sidewalks of congested downtown streets, (2) random spatial sampling, in which samples were collected at randomly selected points in the urban grid, and (3) specialized sampling in the immediate vicinity of the air monitoring station. The results indicate that pedestrians on downtown streets in San Jose can be exposed to concentrations above the federal air quality standards without these values being observed at the air monitoring station. There also is evidence that, at any instant of time, similar values of carbon monoxide exist throughout this city (within a 13-square mile area), provided that measurements are not made in close proximity to streets. Furthermore, the higher concentrations observed in the immediate vicinity of streets decrease quite rapidly with increasing horizontal distance from these streets. These findings, in the view of the authors, raise serious doubts as to whether it is possible to determine if air quality standards as currently defined are actually being met in urban areas using data from present-day air monitoring stations.