Elevated Carbon Monoxide Concentrations Research Articles

Investigation of the pollutant load of artisanal-refined gasoline in the Niger Delta region of Nigeria and its implications on air quality

In order to examine the gaseous pollutants generated by artisanal refined gasoline and the contribution to air pollution associated with such combustion in the Niger-Delta region of Nigeria, this study collected a sample of indigenously refined gasoline product each from thirty (30) different randomly selected artisanal camps in the Niger-Delta region and subjected all the collected samples to combustion. Fifty (50) ml of each gasoline sample was combusted at controlled conditions, and the concentrations of gaseous emissions from the process were measured using a combustion emission analyser. Pollutants characterised by the Department of Petroleum Resources which include sulphur dioxide (SO2), carbon monoxide (CO), oxides of nitrogen (NOx), hydrocarbons (HC) and carbon dioxide (CO2) were characterised. The average concentrations of the emissions were 211.50 mg/m3, 7.18 mg/m3, 17.51 mg/m3, 3011.33 mg/m3, and 500.39 mg/m3 for CO, NOx, SO2, CO2, and HC respectively. The concentrations of SO2 and NOx measured were within the Federal Environmental Protection Agency (FEPA) set limits for combustion emissions from stationary sources but breached World Health Organization (WHO), World Bank and Environmental Guidelines and Standard for Petroleum Industry in Nigeria (EGASPIN) set limits. The concentrations of CO and HC exceeded FEPA, WHO, World Bank and EGASPIN set limits and hazardous on Air Quality Index (AQI) classification. Elevated concentrations of CO and HC in the atmosphere pose a major threat to ambient air quality and human health, especially in locations where artisanal-refined fuel is predominantly utilised. Associated risks include poor visibility, occurrence of acid rain, blood poisoning and cancer-related diseases. In addition to these effects are the worsening global warming crises associated with CO2 emission, a major product of fossil fuel combustion.

Endogenous carbon monoxide (CO) as a modulating factor of molecular biological clock in the hypothalamic structures involved in light transmission in pig and wild boar hybrid during long and short day season.

Mature males of a wild boar-pig crossbreed, during the long and short day season, were used for the study which demonstrates that the chemical light carrier CO regulates the expression of biological clock genes in the hypothalamus via humoral pathways. Autologous blood with experimentally elevated concentrations of endogenous CO (using lamps with white light-emitting diodes) was infused into the ophthalmic venous sinus via the right dorsal nasal vein. Molecular biology methods: qPCR and Western Blot were used to determine the expression of genes and biological clock proteins. The results showed that elevated endogenous CO levels, through blood irradiation, induces changes in genes expression involved in the functioning of the main biological clock located in suprachiasmatic nuclei. Changes in the expression of the transcription factors Bmal1, Clock and Npas2 have a similar pattern in both structures, where a very large decrease in gene expression was shown after exposure to elevated endogenous CO levels. The changes in the gene expression of PER 1-2, CRY 1-2, and REV-ERB α-β and ROR β are not the same for both POA and DH hypothalamic structures, indicating that both structures respond differently to the humoral signal received. The results indicate that CO is a chemical light molecule whose production in an organism depends on the amount of light. An adequate amount of light is an essential factor for the proper functioning of the main biological clock.

Ambient air pollution and epileptic seizures: A panel study in Australia.

ObjectiveEmerging evidence has shown that ambient air pollution affects brain health, but little is known about its effect on epileptic seizures. This work aimed to assess the association between daily exposure to ambient air pollution and the risk of epileptic seizures.MethodsThis study used epileptic seizure data from two independent data sources (NeuroVista and Seer App seizure diary). In the NeuroVista data set, 3273 seizures were recorded using intracranial electroencephalography (iEEG) from 15 participants with refractory focal epilepsy in Australia in 2010–2012. In the seizure diary data set, 3419 self‐reported seizures were collected through a mobile application from 34 participants with epilepsy in Australia in 2018–2021. Daily average concentrations of carbon monoxide (CO), nitrogen dioxide (NO2), ozone (O3), particulate matter ≤10 μm in diameter (PM10), and sulfur dioxide (SO2) were retrieved from the Environment Protection Authority (EPA) based on participants’ postcodes. A patient‐time‐stratified case‐crossover design with the conditional Poisson regression model was used to determine the associations between air pollutants and epileptic seizures.ResultsA significant association between CO concentrations and epileptic seizure risks was observed, with an increased seizure risk of 4% (relative risk [RR]: 1.04, 95% confidence interval [CI]: 1.01–1.07) for an interquartile range (IQR) increase of CO concentrations (0.13 parts per million), whereas no significant associations were found for the other four air pollutants in the whole study population. Female participants had a significantly increased risk of seizures when exposed to elevated CO and NO2, with RRs of 1.05 (95% CI: 1.01–1.08) and 1.09 (95% CI: 1.01–1.16), respectively. In addition, a significant association was observed between CO and the risk of subclinical seizures (RR: 1.20, 95% CI: 1.12–1.28).SignificanceDaily exposure to elevated CO concentrations may be associated with an increased risk of epileptic seizures, especially for subclinical seizures.

Spatial Disparity of Meteorological Impacts on Carbon Monoxide Pollution in China during the COVID-19 Lockdown Period.

Lockdown due to the novel coronavirus disease 2019 (COVID-19) pandemic offers a unique opportunity to study the factors governing the variation in air pollution. A number of studies have investigated the cause underlying the occurrence of heavy haze pollution around the world during the lockdown period. However, information about spatiotemporal variations in gaseous pollutants and detailed quantifications of potential meteorological (METRO) impacts are limited. Ground measurements show that carbon monoxide (CO) pollution deteriorated in northern China despite strict control of human and industrial activities during the lockdown period in early 2020. In this study, a four-dimensional decomposition model was used to quantitatively extract the METRO impacts on the CO pollution over China. The results show that weakened winds elevated CO concentrations near Beijing and in northeastern China. Increased temperatures slightly elevated CO concentrations in northern and eastern China but reduced CO concentrations in northwestern China. Remarkable amounts of CO increases in northern China (e.g., by 0.21 mg/m3 within Beijing) were explained by anomalously high humidity, which could be associated with an enhanced interaction between aerosol and the boundary layer. After excluding the METRO impacts, the CO concentrations drastically declined across China (e.g., by 0.22 mg/m3 within Beijing), indicating that the lockdown indeed greatly lessened CO concentrations. However, the adverse METRO conditions counteracted the beneficial outcomes of emission reductions, leading to a deterioration of the CO pollution in northern China. These results indicate that the METRO factors can play a critical role in worsening air pollution despite a strict control of anthropogenic emissions.

Carbon Monoxide Emissions from Corn Silage

Carbon monoxide (CO) emissions from corn silage were observed using Fourier Transform Infrared (FTIR) spectroscopy and laser spectroscopy. In the first experiment, corn silage was produced using laboratory bucket silos. Air samples were collected from the bucket silos during the first week of ensiling and analyzed using a low-resolution Bruker FTIR spectrometer coupled with a long optical path length White Cell. The CO concentration in the bucket silo gas, derived from the FTIR spectra using the LINEFIT program, was as high as 48.0 ppm. In the second experiment, air samples were collected through a flux chamber from an Ag-Bag silage pile on a commercial dairy that was opened several months after ensiling. The Ag-Bag air samples were analyzed using a high-resolution Bruker FTIR spectrometer, and CO concentrations were retrieved to be 6.83 ppm, corresponding to an area emission rate of 33.7 mg/(hour ·m2). An LGR N2O/CO gas analyzer based on infrared laser spectroscopy was also used to measure the CO concentrations from the same flux chamber. Elevated CO concentrations were observed from these silage sources. The present study revealed that CO was emitted by corn silage during different phases of ensiling. Annual CO emissions from the corn silage were estimated to be much lower than those from the well-known emission categories in San Joaquin Valley (SJV) and California, but comparable to those from food and agricultural sources in the SJV. It is also confirmed that FTIR spectroscopy is a viable method for measuring CO concentrations in complex gas mixtures, such as silage gas.

Carbon monoxide (CO) emissions and its tropospheric variability over Pakistan using satellite-sensed data

This study presents major anthropogenic sources of carbon monoxide (CO) in Pakistan and discusses the spatio-temporal variability of tropospheric CO over Pakistan and neighboring regions of Afghanistan, India and Iran for a period from 2003 to 2012 using satellite-sensed (AIRS/AMSU) data. The results show a large spatio-temporal variability of CO over the study region mostly associated with anthropogenic activities such as crop residue burning, vehicular transport, and electricity and energy generation, and local meteorology. The annual mean value of tropospheric CO is observed to be 115±2ppbv that remains almost steady during the study period with decadal increase of only 2%. Due to more anthropogenic emissions of CO and its transport, the eastern zone shows a higher average value of 122±2ppbv with 2.7% decadal increase than the western zone (111±3ppbv with 1.4% decadal increase). Elevated concentrations of CO have been observed over the Indo-Gangetic Basin, Lahore, Karachi, and Delhi. During the study period large fluctuations in CO mean monthly values are found ranging from 99ppbv to 131ppbv. The fact that, in spite of a large increase in the CO emissions from 2003 to 2012, its average concentration remains almost stable indicates that a large scale regional transport contributes substantially to the tropospheric CO. Carbon monoxide concentrations exhibit a strong seasonal pattern with maximum amplitude in spring and minimum in autumn. July is found to have the highest decadal increasing trend of 13% followed by August at 8%, whereas May has the highest decreasing trend of −8% followed by November at −4.4%.

What could have caused pre-industrial biomass burning emissions to exceed current rates?

Abstract. Recent studies based on trace gas mixing ratios in ice cores and charcoal data indicate that biomass burning emissions over the past millennium exceeded contemporary emissions by up to a factor of 4 for certain time periods. This is surprising because various sources of biomass burning are linked with population density, which has increased over the past centuries. We have analysed how emissions from several landscape biomass burning sources could have fluctuated to yield emissions that are in correspondence with recent results based on ice core mixing ratios of carbon monoxide (CO) and its isotopic signature measured at South Pole station (SPO). Based on estimates of contemporary landscape fire emissions and the TM5 chemical transport model driven by present-day atmospheric transport and OH concentrations, we found that CO mixing ratios at SPO are more sensitive to emissions from South America and Australia than from Africa, and are relatively insensitive to emissions from the Northern Hemisphere. We then explored how various landscape biomass burning sources may have varied over the past centuries and what the resulting emissions and corresponding CO mixing ratio at SPO would be, using population density variations to reconstruct sources driven by humans (e.g., fuelwood burning) and a new model to relate savanna emissions to changes in fire return times. We found that to match the observed ice core CO data, all savannas in the Southern Hemisphere had to burn annually, or bi-annually in combination with deforestation and slash and burn agriculture exceeding current levels, despite much lower population densities and lack of machinery to aid the deforestation process. While possible, these scenarios are unlikely and in conflict with current literature. However, we do show the large potential for increased emissions from savannas in a pre-industrial world. This is mainly because in the past, fuel beds were probably less fragmented compared to the current situation; satellite data indicates that the majority of savannas have not burned in the past 10 yr, even in Africa, which is considered "the burning continent". Although we have not considered increased charcoal burning or changes in OH concentrations as potential causes for the elevated CO concentrations found at SPO, it is unlikely they can explain the large increase found in the CO concentrations in ice core data. Confirmation of the CO ice core data would therefore call for radical new thinking about causes of variable global fire rates over recent centuries.

Effect of air pollution on onset of acute coronary syndrome in susceptible subgroups

While long-term exposure to air pollutants is associated with an increase in heart diseases and mortality, little information is available about the short-term effects of air pollution. This case-crossover study assessed the relationship of particulate matter (PM10) and carbon monoxide (CO) levels with hospital admission for acute coronary syndrome in Tehran, Islamic Republic of Iran. We interviewed 250 patients with a first episode of acute coronary syndrome and obtained data from hospital records and Tehran Air Quality Control Company. The risk of acute coronary syndrome was significantly associated with elevated concentrations of CO the day before the event (OR 1.18; 95% CI: 1.03-1.34) but not significantly with PM10 (OR 1.00; 95% CI: 0.99-1.02). Stratification by age, sex, diabetes, hypertension and smoking status did not affect the results, but women were more susceptible than men to CO levels (OR for women/men 1.68; 95% CI: 1.25-2.26).

Comparing changes in air pollutant concentration before and after cook-stove replacement in rural Ghana

Background and Aims: Using novel, low cost, real-time air quality monitors,we performed a pilot study to analyze the impact of transitioning from open flame cooking to efficient, low emission cookstoves (Envirofit) in a region of Northern Ghana where studies of meningitis epidemics and climate are currently underway. These emissions are important since exposure to air pollution may be a contributing factor towards meningitis transmission and susceptibility. Methods: Monitors were equipped with sensors to measure concentration of total volatile organic compounds (VOCs), ozone, carbon monoxide (CO), and carbon dioxide (CO2). Typical cooking takes place in a enclosed room with an open doorway and burns dried millet stalks between three rocks on which a pot sits. The monitors were placed inside the enclosed cooking areas at 6 sites. Results: Cooking resulted in elevated concentrations of CO, CO2, and total VOCs. These three pollutants were positively correlated during cooking with correlation coefficients ranging from 0.34 to 0.88. The cookstoves emit between 1/5 and 1/18 of the combusted carbon as CO. During cooking events, concentrations of those three pollutants, which are products of combustion, were negatively correlated with ozone concentrations, as expected since emissions of nitrogen oxides from the cookstoves consume ambient ozone. After installing the cookstoves, CO2 concentrations decreased, but VOCs and CO increased slightly. Conclusions: Low cost portable monitors are robust and effective at analyzing variations of concentrations over time. We applied these monitors to evaluate the emissions and air quality in kitchens of rural Ghana before and after new cookstoves were put into use. It is yet unclear whether the long-term use of Envirofit stoves will lead to reduced exposure to various air pollutants within kitchens.

Emission of Carbon Monoxide During Composting of Municipal Solid Waste

Elevated concentrations of carbon monoxide (CO) have been observed at the enclosed municipal waste composting facility (ECF) in Edmonton, Canada. Elevated concentrations of CO in an enclosed facility pose a potential health risk to workers. The objectives in this study were to: (1) assess temporal and spatial variability of CO emissions from the composting bays in the ECF using Fourier Transform Infrared (FTIR) spectroscopy; and (2) identify any correlations between the CO emission rate and the physicochemical properties of the compost through bench-scale incubation experiments. Repeated gas measurements were taken above and within the compost bed in the ECF using a probe connected to an FTIR gas analyzer, which continuously collected concentration data. These preliminary field measurements showed maximum CO concentrations of 112 μL−1 within the compost. Autoclaved and non-sterilized compost samples from the ECF were incubated under aerobic and hypoxic conditions, and gas emissions were quantified using gas chromatography (GC). These trials showed a positive correlation between CO emission rate and incubation temperature for all samples, indicating a physico-chemical source of CO generation. Lower concentrations of CO were observed in the non-sterilized compost under both aerobic and anaerobic conditions, presumably due to the microbial metabolism of CO.

Occupational Health and Safety Assessment of Exposure to Jet Fuel Combustion Products in Air Medical Transport

Introduction. Transport medicine personnel are potentially exposed to jet fuel combustion products. Setting-specific data are required to determine whether this poses a risk. Objective. This study assessed exposure to jet fuel combustion products, compared various engine ignition scenarios, and determined methods to minimize exposure. Methods. The Beechcraft King Air B200 turboprop aircraft equipped with twin turbine engines, using a kerosene-based jet fuel (Jet A-1), was used to measure products of combustion during boarding, engine startup, and flight in three separate engine start scenarios (“shielded”: internal engine start, door closed; “exposed”: ground power unit start, door open; and “minimized”: ground power unit right engine start, door open). Real-time continuous monitoring equipment was used for oxygen, carbon dioxide, carbon monoxide, nitrogen dioxide, hydrogen sulfide, sulfur dioxide, volatile organic compounds, and particulate matter. Integrated methods were used for aldehydes, polycyclic aromatic hydrocarbons, volatile organic compounds, and aliphatic hydrocarbons. Samples were taken in the paramedic breathing zone for approximately 60 minutes, starting just before the paramedics boarded the aircraft. Data were compared against regulated time-weighted exposure thresholds to determine the presence of potentially harmful products of combustion. Results. Polycyclic aromatic hydrocarbons, aldehydes, volatile organic compounds, and aliphatic hydrocarbons were found at very low concentrations or beneath the limits of detection. There were significant differences in exposures to particulates, carbon monoxide, and total volatile organic compound between the “exposed” and “minimized” scenarios. Elevated concentrations of carbon monoxide and total volatile organic compounds were present during the ground power unit–assisted dual-engine start. There were no appreciable exposures during the “minimized” or “shielded” scenarios. Conclusion. Air medical personnel exposures to jet fuel combustion products were generally low and did not exceed established U.S. or Canadian health and safety exposure limits. Avoidance of ground power unit–assisted dual-engine starts and closing the hangar door prior to start minimize or eliminate the occupational exposure.

Air Quality and Cardiovascular Health

Ambient particulate matter has been associated consistently with an increased risk for mortality largely due to cardiovascular diseases.1 Although the relative risk estimates from epidemiological studies are small, they apply to almost the entire population of the United States. Consequently, exposure to ambient particles produces considerable burden of disease, and its mitigation offers the benefit of improving life expectancy.2 Articles see pp 941 and 949 Over the past decade, research has substantiated the understanding of the pathophysiological mechanisms linking ambient particles to the cardiovascular system3,4 once it was noted that ambient air pollution elicits systemic inflammatory responses in the general population.5 An update of the American Heart Association statement on air pollution and cardiovascular disease3 is under way. Mechanisms considered for active and secondhand smoke as well as ambient air pollution are strikingly similar.4,6,7 They include progression of atherosclerotic plaques to vulnerable forms, prothrombotic states, endothelial dysfunction, and altered autonomic nervous system control (Figure). Increased systemic oxidative stress is considered the key mechanism responsible for most of these pathophysiological changes. Increased risks for cardiovascular disease in general and coronary artery disease in particular have been documented for active and secondhand smoke as well as ambient particulate matter. Deep venous thrombosis has been added to this list recently.8 Figure. Overview on pathomechanism linking ambient air pollution,4 secondhand smoke,7 and active smoking to acute coronary syndromes. Nevertheless, the public health relevance of particulate matter in the light of the smoking literature remains hotly debated. Smokers are exposed to considerably higher cumulative doses of particulate matter than the general nonsmoking population. Mortality due to low doses of ambient particles may be considered counterintuitive compared with doses of particles tolerated by smoking individuals. A systematic assessment of the exposure-response function ranging from low doses of inhaled particles …

Carbon monoxide concentration in donated blood: relation to cigarette smoking and other sources

Carbon monoxide (CO) is normally present in the human body due to endogenous production of CO. CO can also be inhaled by exposure to external sources such as cigarette smoke, car exhaust, and fire. The purpose of this study was to investigate CO concentrations in blood from 410 blood donors at the blood center in Umeå, Sweden. To further evaluate the effects of cigarette smoking on CO concentrations, the elimination time for CO was examined in six volunteer smokers after a smoked cigarette. Blood samples from whole blood donors were obtained during the blood center's routine operation. In connection with blood donations, demographic and behavioral data were collected from the donors. The CO concentration was determined using gas chromatography. The majority of blood donors had approximately the same CO concentration (mean, 84.5 micromol/L). In 6 percent of the samples, the concentrations were higher than 130 micromol per L. The highest CO concentration was 561 micromol per L. The main source for these high CO concentrations appeared to be cigarette smoking. In the volunteer smokers, the elimination time after a smoked cigarette varied significantly, with elimination half-lives from 4.7 to 8.4 hours. These results show that blood bank red blood cell bags may have CO concentrations above the physiologic level. The time interval between cigarette smoking and blood donation seems to be a particularly important factor for elevated CO concentrations.

Carbon monoxide–releasing molecule tricarbonyldichlororuthenium (II) dimer induces concentration-dependent alterations in the electrophysiological properties of axons in mammalian spinal cord

Traumatic spinal cord injury (SCI) typically involves intraparenchymal hemorrhage and a cascade of inflammatory and cytotoxic processes leading to tissue necrosis and apoptosis. A consequence of the hemorrhage is the accumulation of deoxygenated heme proximal and distal to the epicenter of the lesion. The heme oxygenase (HO) system is an endogenous heme degradation system and is upregulated following neurotrauma. The breakdown of heme via HO activity yields the byproducts carbon monoxide (CO), biliverdin, and iron. CO has documented neuromodulatory properties; however, the effects of elevated concentrations of CO on axonal conduction in the spinal cord have not previously been studied. The present study tested the hypothesis that CO causes alterations in the electrophysiological properties of axons within the isolated guinea-pig spinal cord. Ex vivo spinal cord preparations were exposed to 100, 500, and 1000 μM concentrations of the carbon monoxide–releasing molecule (CORM) 2 for 30 min in a double sucrose gap electrophysiological recording system and the compound action potential (CAP) and membrane potential (CMP) were recorded continuously during pretreatment, CORM-2 treatment, and washout (30 min) with Krebs’ solution. CAP amplitude and area were significantly ( P<0.05) reduced following treatment with 500 and 1000 μM CORM-2 and did not recover during washout. No effect on CMP was observed, however, stimulus-peak latency did increase significantly ( P<0.05) following CORM-2 treatment at these concentrations, and a decrease in the amplitude of the second CAP elicited by paired-pulse stimulation was also evident at interpulse intervals of 2 and 4 ms. These results are consistent with a CO-induced alteration in axonal conduction, possibly attributable to modified Na + channel conductance. They also identify a new mechanism by which post-traumatic hemorrhage contributes to the neurological deficits observed following SCI.

Carbon Monoxide Inhibits Hypoxia/Reoxygenation-Induced Apoptosis and Secondary Necrosis in Syncytiotrophoblast

Pre-eclampsia, a hypertensive disorder of pregnancy, affects 5 to 7% of pregnancies. Oxidative stress-induced placental injury and subsequent release of placental debris into the maternal circulation are key pathogenic events in the progression of pre-eclampsia. Women who smoke cigarettes throughout pregnancy are 33% less likely to develop this disorder than nonsmoking women. We postulated that elevated carbon monoxide concentrations in serum of smoking women inhibits apoptosis and debris shedding of trophoblast cells exposed to ischemia-reperfusion injury because carbon monoxide has cytoprotective effects on endothelial and smooth muscle cells in culture. This may be responsible for the reduced risk of pre-eclampsia in smoking women. To assess the cytoprotective properties of carbon monoxide within placental tissue, carbon monoxide treatments were administered to in vitro hypoxia/reoxygenation-insulted villous explants cultured from term human placenta. Induction of apoptosis was assessed using molecular and morphological approaches. Placental villous explants treated with carbon monoxide demonstrated 60% less hypoxia/reoxygenation-induced apoptosis in the differentiated syncytiotrophoblast layer compared with untreated explants undergoing a similar insult. In addition, retention of intact syncytial membranes was observed in carbon monoxide-treated explants. These observations indicate that carbon monoxide has potent antiapoptotic properties within human placenta and may hold therapeutic potential in the treatment of pre-eclampsia.

Observations of Asian air pollution in the free troposphere at Mount Bachelor Observatory during the spring of 2004

This paper describes the chemical, aerosol, and meteorological measurements taken at Mount Bachelor Observatory (MBO), a new mountaintop site in central Oregon, USA (44.0°N, 121.7°W, 2763 m above mean sea level). During the initial campaign (28 March to 19 May 2004) we evaluated the utility of this location as a site to observe the global atmosphere, especially the free troposphere (FT). We observed some boundary layer (BL)/upslope flow during the daytime, which produced a 37–62% higher average water vapor mixing ratio (WV) compared to radiosonde data taken from similar altitudes in western Oregon. However, recently subsided air masses with low WV contained significantly elevated concentrations of carbon monoxide (CO), total gaseous mercury (TGM), and ozone (O3), (25 ppbv, 0.16 ng/m3, and 13.9 ppbv, respectively), compared to periods with high‐WV measurements. These enhancements represent a significant influence from Asian long‐range transport (ALRT). One specific time period (“event”) on 25 April produced some of the largest CO, TGM, O3, and particulate scattering (σsp) measurements ever seen along the West Coast due to ALRT. Enhancement ratios between these species are consistent with the major source being Asian industrial emissions. In particular, the ΔTGM/ΔCO enhancement ratio was 0.0045–0.0048 ng/m3/ppbv for all ALRT events, similar to the value previously obtained from pollution plumes directly downwind of east Asia. A smaller pollution event of North American origin produced a ΔTGM/ΔCO value of only 0.0013 ng/m3/ppbv, suggesting that the ΔTGM/ΔCO value is an effective tracer of ALRT. Finally, thousands of kinematic back trajectories were calculated for each event to evaluate sources and transport processes.

Carbon monoxide, methane and carbon dioxide columns retrieved from SCIAMACHY by WFM-DOAS: year 2003 initial data set

Abstract. The near-infrared nadir spectra measured by SCIAMACHY on-board ENVISAT contain information on the vertical columns of important atmospheric trace gases such as carbon monoxide (CO), methane (CH4), and carbon dioxide (CO2). The scientific algorithm WFM-DOAS has been used to retrieve this information. For CH4 and CO2 also column averaged mixing ratios (XCH4 and XCO2) have been determined by simultaneous measurements of the dry air mass. All available spectra of the year 2003 have been processed. We describe the algorithm versions used to generate the data (v0.4; for methane also v0.41) and show comparisons of monthly averaged data over land with global measurements (CO from MOPITT) and models (for CH4 and CO2). We show that elevated concentrations of CO resulting from biomass burning have been detected in reasonable agreement with MOPITT. The measured XCH4 is enhanced over India, south-east Asia, and central Africa in September/October 2003 in line with model simulations, where they result from surface sources of methane such as rice fields and wetlands. The CO2 measurements over the Northern Hemisphere show the lowest mixing ratios around July in qualitative agreement with model simulations indicating that the large scale pattern of CO2 uptake by the growing vegetation can be detected with SCIAMACHY. We also identified potential problems such as a too low inter-hemispheric gradient for CO, a time dependent bias of the methane columns on the order of a few percent, and a few percent too high CO2 over parts of the Sahara.

Determination of carbon monoxide (CO) in rodent tissue: Effect of heme administration and environmental CO exposure

Carbon monoxide (CO), produced endogenously during heme degradation, is considered a messenger molecule in vascular and neurologic tissues. To study this role, it is important to determine CO concentration in target tissues pre- and post-perturbations. Here, we describe a sensitive and reproducible method, which is linear and accurate, and provide some examples of its application for quantitation of CO concentrations in tissues pre- and post-perturbations. Tissues from adult rats and mice were sonicated (20% w/w), and volumes representing 0.04–8 mg fresh weight (FW) were incubated at 0 °C for ⩾30 min with sulfosalicylic acid. CO liberated into the headspace was quantitated by gas chromatography. Tissue CO concentrations (mean ± SD, pmol CO/mg FW) were as follows: blood (47 ± 10, 45 ± 5), muscle (4 ± 4, 10 ± 1), kidney (5 ± 2, 7 ± 2), heart (6 ± 3, 6 ± 1), spleen (11 ± 3, 6 ± 1), liver (4 ± 1, 5 ± 1), intestine (2 ± 1, 4 ± 2), lung (2 ± 1, 3 ± 1), testes (1 ± 1, 2 ± 1), and brain (2 ± 1, 2 ± 0) in untreated rat ( n = 3) and mouse ( n = 5), respectively. Between the rat and the mouse, only CO concentrations in the muscle and spleen were significantly different ( p ⩽ 0.05). Endogenous CO generation, after administration of heme arginate to mice ( n = 3), increased CO concentrations by 0–43 pmol/mg FW. Exposure of mice ( n = 3) to 500 ppm CO for 30 min yielded significantly elevated CO concentrations by 4–2603 pmol/mg FW in all tissues over the native state. While blood had the highest CO concentration for all conditions, muscle, kidney, heart, spleen, and liver, all rich in hemoglobin and/or other CO-binding hemoproteins, also contained substantial CO concentrations. Intestine, lung, testes, and brain contained the lowest CO concentrations.

Tracing the origin and ages of interlaced atmospheric pollution events over the tropical Atlantic Ocean with in situ measurements, satellites, trajectories, emission inventories, and global models

During a west to east crossing of the tropical Atlantic Ocean in October–November 2002 on R/V Meteor (M55), carbon monoxide (CO) and ozone were continuously monitored, and pressurized air samples were collected and later analyzed in the laboratory for various volatile organic compounds. A sequence of alternating CO and propane rich events were observed over the east Atlantic, the events of enhanced carbon monoxide being out of phase with those observed for propane. A combined study of air mass origin (back trajectories and backward emission sensitivity calculations) and source region distribution comparison (CO satellite data from MOPITT and propane emission data from the EDGAR database) showed that the CO events were due to African biomass burning emissions, whereas the propane events were due to industrial emissions from areas of northern Africa. Both events were associated with elevated ozone. A comparison of the measured concentrations of CO and propane with those simulated by the global Model of Atmospheric Transport and Chemistry‐Max Planck Institute for Chemistry (MATCH‐MPIC) shows that the model reproduces the general longitudinal gradient observed for both compounds and simulates elevated CO concentrations during the pollution events. However, it systematically overestimates the CO mixing ratios. It is suggested that the northern African biomass burning emissions used in the model are not distributed correctly (incorrect timing) and, in particular, that too high emissions from the region “northern Sudan‐Sahel” are used for this period. The model does not capture the influence from industrial emissions from northern Africa, which may be caused by too strong diffusion of the plume.

A survey of carbon monoxide in student rented flats in London, UK

Carbon monoxide (CO) is a potentially lethal gas which cannot be detected by the senses. Each year in the UK, at least 50 people die from acute CO poisoning caused by emissions from gas heaters. Many hundreds more suffer symptoms of chronic poisoning, including headaches, sickness and chest pains, which are easily misdiagnosed. CO concentrations were measured in 20 student rented flats with gas heating appliances, in London. In 16 flats, peak concentrations did not exceed 10ppm and 11 of these did not exceed 2ppm during the eight hour monitoring period. Only one flat exceeded WHO guideline concentrations, having a one hour mean concentration of 36ppm and the highest peak concentration of 86ppm. One other flat had one hour and eight hour means approaching WHO guideline concentrations. Further research and monitoring of CO levels in UK homes is recommended to determine the extent of this problem and to evaluate contributions from different sources. Action, including further monitoring, is needed to reduce the levels of CO in homes with elevated CO concentrations and to increase awareness of the dangers and symptoms of CO poisoning.