scholarly journals Feasibility of Using Oscillatory Catalytic Oxidation Phenomenon for Selective Carbon Monoxide Sensing

1987 ◽  
Vol 12 (4) ◽  
pp. 291-301 ◽  
Author(s):  
Heikki Torvela
Keyword(s):  
Carbon Monoxide ◽  
Tin Dioxide ◽  
Ambient Air ◽  
Major Influence ◽  
Processing Conditions ◽  
Response Characteristics ◽  
Co Concentration ◽  
Different Temperatures ◽  
Oscillatory Response ◽  
Co Concentrations

Tin dioxide based sensors with different additives were constructed and tested in air environment containing carbon monoxide. Conductance oscillations were observed in samples containing palladium but not in those without. Oscillations occurred at temperatures ranging from 150℃ to 320℃. Within this temperature region the range of CO concentrations at which oscillations appeared became higher as the test temperature increased. The lowest CO concentration at which oscillations were observed was 200 ppm and the highest 10000 ppm.By comparing sensor responses obtained in synthetic and ambient air it was concluded that water vapour has a major influence on oscillations and increases the frequency. The ranges of CO concentrations in which oscillations occurred at different temperatures, however, remained roughly the same in both environments. It was also noticed that processing conditions had an influence on the oscillatory response characteristics of the sensors.

Competitive inhibition of carbon monoxide transport: evidence against a carrier

1981 ◽  
Vol 50 (5) ◽  
pp. 1061-1064 ◽  
Author(s):  
D. Z. Rubin ◽  
D. Fujino ◽  
C. Mittman ◽  
S. M. Lewis
Keyword(s):  
Carbon Monoxide ◽  
Competitive Inhibition ◽  
Normal Adult ◽  
Gas Mixture ◽  
Diffusing Capacity ◽  
Constant Amount ◽  
Pulmonary Diffusing Capacity ◽  
Co Concentration ◽  
Carrier Molecule ◽  
Co Concentrations

The existence of a saturable carbon monoxide (CO) carrier in the lung remains controversial. The carrier hypothesis was invoked to explain data that indicated that pulmonary diffusing capacity for CO (DLCO) decreases with increasing CO concentration. To test this hypothesis, we measured DLCO in 14 normal adult subjects at three alveolar CO concentrations (60, 660, and 2,060 ppm). Each mixture contained a constant amount of labeled C18O (60 ppm) and a balance of unlabeled C16O. If a saturable carrier exists at increasing CO concentrations, the unlabeled CO would compete for most of the sites on the carrier molecule, effectively inhibiting the uptake of the labeled C18O. C18O diffusing capacities (mean +/- SD) for the three levels of CO were 34.9 +/- 5.6, 33.0 +/- 6.0, and 34.7 +/- 7.8. There were no significant differences (P greater than 0.2) among the three levels. In another group of subjects we repeated the study using a gas mixture containing 130 ppm C18O. No significant differences were found. As a result, we find no evidence to support a CO carrier hypothesis.

scholarly journals Increased heme catabolism in critically ill patients: correlation among exhaled carbon monoxide, arterial carboxyhemoglobin, and serum bilirubin IXα concentrations

2006 ◽  
Vol 290 (1) ◽  
pp. L114-L119 ◽  
Author(s):  
Hiroshi Morimatsu ◽  
Toru Takahashi ◽  
Kyoichiro Maeshima ◽  
Kazuyoshi Inoue ◽  
Tomoko Kawakami ◽  
...  
Keyword(s):  
Carbon Monoxide ◽  
Critically Ill ◽  
Critically Ill Patients ◽  
Linear Regression Analysis ◽  
Multivariate Linear Regression Analysis ◽  
Arterial Blood ◽  
Exhaled Air ◽  
Co Concentration ◽  
Exhaled Carbon Monoxide ◽  
Co Concentrations

It has been reported that exhaled carbon monoxide (CO) concentrations and arterial carboxyhemoglobin (CO-Hb) concentration in blood may be increased in critically ill patients. However, there was no study that examined correlation among amount of CO in exhaled air, CO-Hb concentrations in erythrocytes, and bilirubin IXα (BR) in serum, i.e., the three major indexes of heme catabolism, within the same subject. Here, we examined CO concentrations in exhaled air, CO-Hb concentrations in arterial blood, and BR levels in serum in 29 critically ill patients. Measurements of exhaled CO, arterial CO-Hb, and serum total BR have been done in the intensive care unit. As control, exhaled CO concentration was also measured in eight healthy volunteers. A median exhaled CO concentration was significantly higher in critically ill patients compared with control. There was significant correlation between CO and CO-Hb and CO and total BR level. We also found CO concentrations correlated with indirect BR but not direct BR. Multivariate linear regression analysis for amount of exhaled CO concentrations also showed significant correlation with CO-Hb and total BR, despite the fact that respiratory variables of study subjects were markedly heterogeneous. We found no correlation among exhaled CO, patients’ severity, and degree of inflammation, but we found a strong trend of a higher exhaled CO concentration in survivors than in nonsurvivors. These findings suggest there is an increased heme breakdown in critically ill patients and that exhaled CO concentration, arterial CO-Hb, and serum total BR concentrations may be useful markers in critically ill conditions.

scholarly journals Exposure to Carbon Monoxide while Commuting in Popular Modes of Transport in Karachi, Pakistan

2020 ◽  
Vol 63 (2) ◽  
pp. 123-129
Author(s):  
Zafar Iqbal Shams ◽  
Muhammad Saqib Khan ◽  
Syed Taha Ahmed ◽  
Rumaisa Ilyas ◽  
Zeeshan Akhtar
Keyword(s):  
Carbon Monoxide ◽  
Human Exposure ◽  
Motor Vehicle ◽  
Motor Vehicles ◽  
Co Concentration ◽  
Baseline Information ◽  
Control Devices ◽  
Low Sulfur ◽  
The City ◽  
Co Concentrations

Motor vehicles are the single largest source of toxic carbon monoxide in Karachi because advance emission control devices are not fitted in them mainly due to non-availability of low sulfur or sulfur-free fuel. On the contrary, commuters' exposure to carbon monoxide has not yet been investigated, while commuting in any motor vehicle of the city. Therefore, the present study investigated commuter's exposure to carbon monoxide, while travelling in nine different popular modes of transport. The exposure to CO concentrations was recorded inside the buses of seven standard routes of the city. Similarly, exposure to ambient carbon monoxide was also explored, while riding a motorbike on two different routes of the city. On an average, he came in contact with 6.82 ± 2.66 ppm CO during 7576 minutes travelling on nine routes of the metropolis. He was exposed to the highest CO concentration (15.20 ± 9.59 ppm), while riding a motorbike through Route 1 that passed through heavily populated neighborhood. Rider's exposure to carbon monoxide was found significantly (p < 0.05) correlated with wind velocity. As a whole, commuter's exposures to carbon monoxide during evening was significantly (p < 0.01) higher than those of the morning sessions. The present study will provide baseline information for reducing human exposure to the deadly carbon monoxide.    

Carbon monoxide exchanges between the human fetus and mother: a mathematical model

1977 ◽  
Vol 232 (3) ◽  
pp. H311-H323 ◽  
Author(s):  
E. P. Hill ◽  
J. R. Hill ◽  
G. G. Power ◽  
L. D. Longo
Keyword(s):  
Mathematical Model ◽  
Air Pollution ◽  
Carbon Monoxide ◽  
Cardiac Output ◽  
Human Fetus ◽  
Alveolar Ventilation ◽  
Co Concentration ◽  
Fetal Oxygenation ◽  
Ventilation Rates ◽  
Co Concentrations

A mathematical model was developed to calculate maternal and fetal carboxyhemoglobin concentrations, [HbCO], as functions of time during and after exposure of the mother to various inspired CO concentrations. Effects of variation in alveolar ventilation rates, pulmonary and placental fiffusing capacities, cardiac output, endogenous carbon monoxide production and other factors were studied. Following a change in the inspired CO concentration, fetal HbCO lags behind maternal HbCO by several hours. During CO uptake, fetal HbCO eventually overtakes maternal, and approaches an equilibrium value as much as 10% higher than the mother's. During CO washout the fetal levels again lag behind the mothers. Results indicate that treatment of pregnant women who have elevated HbCO levels with 100% oxygen reduces the time necessary to reduce the maternal HbCO level as expected, but that the rate of fetal CO elimination is not increased as much as that of the mother. Changes in maternal and fetal HbCO were also calculated for a representative exposure to changing inspired CO levels produced by fluctuating levels of air pollution. Finally, the effects of carboxyhemoglobin on fetal oxygenation were studied, including the effects of high altitude and exercise.

Carbon Monoxide Production from Desflurane, Enflurane, Halothane, Isoflurane, and Sevoflurane with Dry Soda Lime

2001 ◽  
Vol 95 (5) ◽  
pp. 1205-1212 ◽  
Author(s):  
Heimo Wissing ◽  
Iris Kuhn ◽  
Uwe Warnken ◽  
Rafael Dudziak
Keyword(s):  
Carbon Monoxide ◽  
Soda Lime ◽  
Ambient Air ◽  
Volatile Anesthetics ◽  
Laboratory Work ◽  
Clinical Report ◽  
Ambient Temperatures ◽  
Bottom To Top ◽  
Co Concentrations

Background Previous studies in which volatile anesthetics were exposed to small amounts of dry soda lime, generally controlled at or close to ambient temperatures, have demonstrated a large carbon monoxide (CO) production from desflurane and enflurane, less from isoflurane, and none from halothane and sevoflurane. However, there is a report of increased CO hemoglobin in children who had been induced with sevoflurane that had passed through dry soda lime. Because this clinical report appears to be inconsistent with existing laboratory work, the authors investigated CO production from volatile anesthetics more realistically simulating conditions in clinical absorbers. Methods Each agent, 2.5 or 5% in 2 l/min oxygen, were passed for 2 h through a Dräger absorber canister (bottom to top) filled with dried soda lime (Drägersorb 800). CO concentrations were continuously measured at the absorber outlet. CO production was calculated. Experiments were performed in ambient air (19-20 degrees C). The absorbent temperature was not controlled. Results Carbon monoxide production peaked initially and was highest with desflurane (507 +/- 70, 656 +/- 59 ml CO), followed by enflurane (460 +/- 41, 475 +/- 99 ml CO), isoflurane (176 +/- 2.8, 227 +/- 21 ml CO), sevoflurane (34 +/- 1, 104 +/- 4 ml CO), and halothane (22 +/- 3, 20 +/- 1 ml CO) (mean +/- SD at 2.5 and 5%, respectively). Conclusions The absorbent temperature increased with all anesthetics but was highest for sevoflurane. The reported magnitude of CO formation from desflurane, enflurane, and isoflurane was confirmed. In contrast, a smaller but significant CO formation from sevoflurane was found, which may account for the CO hemoglobin concentrations reported in infants. With all agents, CO formation appears to be self-limited.

scholarly journals Modeling of CO Accumulation in the Headspace of the Bioreactor during Organic Waste Composting

Energies ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1367
Author(s):  
Karolina Sobieraj ◽  
Sylwia Stegenta-Dąbrowska ◽  
Jacek A. Koziel ◽  
Andrzej Białowiec
Keyword(s):  
Carbon Monoxide ◽  
Organic Waste ◽  
Short Term ◽  
Surrounding Environment ◽  
Advanced Technologies ◽  
Maximum Value ◽  
Initial Stage ◽  
Co Concentration ◽  
The Impact ◽  
Co Concentrations

Advanced technologies call for composting indoors for minimized impact on the surrounding environment. However, enclosing compost piles inside halls may cause the accumulation of toxic pollutants, including carbon monoxide (CO). Thus, there is a need to assess the occupational risk to workers that can be exposed to CO concentrations > 300 ppm at the initial stage of the process. The objectives were to (1) develop a model of CO accumulation in the headspace of the bioreactor during organic waste composting and (2) assess the impact of headspace ventilation of enclosed compost. The maximum allowable CO level inside the bioreactor headspace for potential short-term occupational exposure up to 10 min was 100 ppm. The composting was modeled in the horizontal static reactor over 14 days in seven scenarios, differing in the ratio of headspace-to-waste volumes (H:W) (4:1, 3:1, 2:1, 1:1, 1:2, 1:3, 1:4). Headspace CO concentration exceeded 100 ppm in each variant with the maximum value of 36.1% without ventilation and 3.2% with the daily release of accumulated CO. The airflow necessary to maintain CO < 100 ppmv should be at least 7.15 m3·(h·Mg w.m.)−1. The H:W > 4:1 and the height of compost pile < 1 m were less susceptible to CO accumulation.

Carbon monoxide fixation by plants

1974 ◽  
Vol 52 (8) ◽  
pp. 1841-1847 ◽  
Author(s):  
R. G. S. Bidwell ◽  
Gail P. Bebee
Keyword(s):  
Carbon Monoxide ◽  
Uptake Rate ◽  
Average Rate ◽  
Fresh Weight ◽  
Tropical Plants ◽  
Gas System ◽  
Co Concentration ◽  
Co Concentrations ◽  
Bean Leaves

Leaves of 35 species of temperate and tropical plants absorbed CO in light from air containing 6 ppm CO at an average rate of 0.19 μl/h g fresh weight. CO absorption was measured by the uptake of 14CO from a closed flowing gas system. CO uptake by bean leaves varied considerably with age. Uptake by nine species having widely different rates of absorption was exactly proportional to CO concentration in the range 0 to 100 ppm CO. Absorbed CO was metabolized either by oxidation to CO2 and fixation as such or by reduction and incorporation into serine. Corn, a C4 plant, emphasized the former pathway and bean, a C3 plant, emphasized the latter pathway. CO had various effects on the photosynthesis of leaves of different species; ranging from being inhibitory at concentrations as low as 65 ppm to exerting no influence, or even permitting an increase in net CO2 fixation at 99% CO because of the absence of O2.Plants do not contribute significantly to the global CO balance because their uptake rate is low at the CO concentration normally encountered in interurban areas. However, their contribution may become very important in or near urban and polluted areas, where elevated CO concentrations are frequently found.

scholarly journals Global soil consumption of atmospheric carbon monoxide: an analysis using a process-based biogeochemistry model

2018 ◽  
Vol 18 (11) ◽  
pp. 7913-7931 ◽  
Author(s):  
Licheng Liu ◽  
Qianlai Zhuang ◽  
Qing Zhu ◽  
Shaoqing Liu ◽  
Hella van Asperen ◽  
...  
Keyword(s):  
Carbon Monoxide ◽  
Soil Moisture ◽  
Soil Temperature ◽  
Air Temperature ◽  
Deposition Velocity ◽  
Oh Radicals ◽  
Co Concentration ◽  
Global Soil ◽  
Net Flux ◽  
Co Concentrations

Abstract. Carbon monoxide (CO) plays an important role in controlling the oxidizing capacity of the atmosphere by reacting with OH radicals that affect atmospheric methane (CH4) dynamics. We develop a process-based biogeochemistry model to quantify the CO exchange between soils and the atmosphere with a 5 min internal time step at the global scale. The model is parameterized using the CO flux data from the field and laboratory experiments for 11 representative ecosystem types. The model is then extrapolated to global terrestrial ecosystems using monthly climate forcing data. Global soil gross consumption, gross production, and net flux of the atmospheric CO are estimated to be from −197 to −180, 34 to 36, and −163 to −145 Tg CO yr−1 (1 Tg = 1012 g), respectively, when the model is driven with satellite-based atmospheric CO concentration data during 2000–2013. Tropical evergreen forest, savanna and deciduous forest areas are the largest sinks at 123 Tg CO yr−1. The soil CO gross consumption is sensitive to air temperature and atmospheric CO concentration, while the gross production is sensitive to soil organic carbon (SOC) stock and air temperature. By assuming that the spatially distributed atmospheric CO concentrations (∼ 128 ppbv) are not changing over time, the global mean CO net deposition velocity is estimated to be 0.16–0.19 mm s−1 during the 20th century. Under the future climate scenarios, the CO deposition velocity will increase at a rate of 0.0002–0.0013 mm s−1 yr−1 during 2014–2100, reaching 0.20–0.30 mm s−1 by the end of the 21st century, primarily due to the increasing temperature. Areas near the Equator, the eastern US, Europe and eastern Asia will be the largest sinks due to optimum soil moisture and high temperature. The annual global soil net flux of atmospheric CO is primarily controlled by air temperature, soil temperature, SOC and atmospheric CO concentrations, while its monthly variation is mainly determined by air temperature, precipitation, soil temperature and soil moisture.

scholarly journals Determining Effective Parameters on CO Concentration in Tehran Air by Sensitivity Analysis based on Neural Network Prediction

2019 ◽  
Vol 11 (2) ◽  
pp. 77-85
Author(s):  
F. Qaderi ◽  
E. Babanezhad ◽  
M. Ebrahimi Ghadi
Keyword(s):  
Neural Network ◽  
Sensitivity Analysis ◽  
Carbon Monoxide ◽  
Wind Speed ◽  
Ambient Air ◽  
Urban Traffic ◽  
Air Pressure ◽  
Effective Parameters ◽  
Urban Density ◽  
Co Concentration

One of the most toxic pollutant gases produced by fossil fuels is carbon monoxide. Hence, the accurate and regular estimation and control of CO in the cities such as Tehran is inevitable. In this research, for the first time, CO concentration in ambient air was predicted based on 12 important urban and meteorological parameters by neural network. Also, the sensitivity analysis of the factors that effect on the concentration of carbon monoxide in Tehran was investigated based on the pollutant concentration predictive model. In this research, the daily statistical data of Tehran metropolis over the course of five consecutive years from 12 factors affecting the amount of carbon monoxide in Tehran, such as population, density, precipitation, temperature, urban traffic, wind speed, gasoil consumption, moisture, air flow, effective vision and air pressure was used. Based on this database, the artificial neural network with the best possible algorithm had been trained to predict this contaminant and root mean square error of model was equal to 2.54. Then, sensitivity analysis was done to find the most effective factor on the concentration of carbon monoxide, urban density and air pressure. In order to control this hazardous contaminant in urban management, these parameters should be taken into account. Based on the result, by preventing the construction of high towers in Tehran, wind speed average will increase and increasing in wind speed (25%) caused to reducing in carbon monoxide concentration (about 12%). Also, prevention of urban density (25%) will cause to prevention of increasing CO concentration (about 10%).

scholarly journals ANALISIS ISOPHLET KONSENTRASI DAN ESTIMASI POTENSI PENURUNAN KARBON MONOKSIDA DI KOTA MEDAN

Jurnal Dampak ◽  
2016 ◽  
Vol 13 (2) ◽  
pp. 51
Author(s):  
Isra' Suryati ◽  
Hafizhul Khair
Keyword(s):  
Carbon Monoxide ◽  
Government Regulation ◽  
Ambient Air ◽  
Mass Transit ◽  
Quality Standard ◽  
Mass Transportation ◽  
Ambient Air Quality ◽  
Grab Sampling ◽  
Co Concentration ◽  
Ambient Air Quality Standard

This study aims to map the concentration of carbon monoxide (CO) in Medan city and to estimate the potential reduction in carbon monoxide in some streets of Medan by applying mass transit based on simulation. This research was conducted by sampling CO in the 12 (twelve) points in Medan by grab sampling. CO concentration was analyzed using NDIR methods by CO Monitor tools. The results showed the concentration of CO in Medan between 1145.2 mg/m3 - 27484,7 mg/m3. This condition is still below the national ambient air quality standard of Government Regulation No. 41, 1999 (30,000 mg/m3). Based on the concentration isophlet map that points that have the highest concentration located in the surrounding roadside such as at Jl. SM Raja. To reduction the CO concentration in the ambient air around the roadside is necessary to plan programs and policies related to transportation. If the scenarios or simulation with application of the concept of mass transportation such as BRT CNG and BRT Diesel in some streets of Medan then will be able to reduce CO emissions of about 25.02% to 29.44%.Keywords: vehicle emissions, carbon monoxide, map isophlet, mass transitABSTRAKPenelitian ini bertujuan untuk memetakan konsentrasi gas karbon monoksida (CO) di Kota Medan dan melakukan estimasi potensi penurunan karbon monoksida di beberapa ruas jalan Kota Medan dengan menerapkan transportasi massal berbasis simulasi. Penelitian ini dilakukan dengan pengambilan sampel CO di 12 (dua belas) titik di Kota Medan secara grab sampling. Konsentrasi CO dianalisis menggunakan metode NDIR dengan alat sampling yaitu CO Monitor. Hasil penelitian menunjukkan konsentrasi CO di Kota Medan antara 1145,2 mg/m3 27484,7mg/m3. Kondisi ini masih dibawah baku mutu udara ambien nasional Peraturan Pemerintah No. 41 tahun 1999 (30.000 mg/m3). Berdasarkan peta isophlet konsentrasi tersebut bahwa titik-titik yang mempunyai konsentrasi tertinggi berlokasi di sekitar jalan salah satunya seperti di Jl. SM Raja. Untuk menurunkan konsentrasi CO di udara ambien di sekitar jalan perlu dilakukan perencanaan program dan kebijakan terkait transportasi. Apabila dilakukan skenario atau simulasi penerapan konsep transportasi massal berupa BRT CNG dan BRT Diesel di beberapa ruas jalan Kota Medan akan mampu mengurangi beban emisi CO sekitar 25,02% sampai dengan 29,44%.Kata kunci : emisi kendaraan, karbon monoksida, peta isophlet, transportasi massal

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