Ambient Carbon Monoxide Levels Research Articles

Association between ambient carbon monoxide levels and hospitalization costs of patients with myocardial infarction: Potential effect modification by ABO blood group

Previous researches have reported the association between air pollution and various diseases. However, few researches have investigated whether air pollutants are associated with the economic loss resulting from patients’ hospitalization, especially the economic loss of hospitalization due to acute cardiovascular events. The purpose of our research was to explore the association between the levels of carbon monoxide (CO), taken as an index of pollution, and the hospitalization costs of myocardial infarction (MI), and the potential effect modification by the ABO blood group. A total of 3237 MI inpatients were included in this study. A multiple linear regression model was used to evaluate the association between ambient CO levels and hospitalization costs of MI patients. Moreover, we performed stratified analyses by age, gender, body mass index (BMI), season, hypertension, and ABO blood types. There was a positive association between the levels of CO in the air and the costs of hospitalization caused by MI. Furthermore, such association was stronger in males, BMI ≥25, <65 years, with hypertension, and non-O blood group. Interestingly, we found the association was particularly significant in patients with blood group B. Overall, our study first found that ambient CO levels could have an impact on the hospitalization costs for MI patients, and those with blood group B can be more sensitive.

Assessment of wood burning versus fossil fuel contribution to wintertime black carbon and carbon monoxide concentrations in Athens, Greece

Abstract. The scope of this study was to estimate the contribution of fossil fuel and wood burning combustion to black carbon (BC) and carbon monoxide (CO) during wintertime, in Athens. For that purpose, in situ measurements of equivalent black carbon (eBC) and CO were simultaneously conducted in a suburban and an urban background monitoring site in Athens during the 3 months of winter 2014–2015. For the deconvolution of eBC into eBC emitted from fossil fuel (BCff) and wood burning (BCwb), a method based on the spectral dependency of the absorption of pure black carbon and brown carbon was used. Thereafter, BCwb and BCff estimated fractions were used along with measured CO concentrations in a multiple regression analysis, in order to quantify the contribution of each one of the combustion sources to the ambient CO levels. For a comparative analysis of the results, we additionally estimated the wood burning and fossil fuel contribution to CO, calculated on the basis of their CO ∕ NOx emission ratios. The results indicate that during wintertime BC and CO are mainly emitted by local sources within the Athens Metropolitan Area (AMA). Fossil fuel combustion, mainly from road traffic, is found to be the major contributor to both eBC in PM2.5 and CO ambient concentrations in AMA. However, wintertime wood burning makes a significant contribution to the observed eBC (of about 30 %) and CO concentrations (on average, 11 and 16 % of total CO in the suburban and urban background sites respectively). Both BC and CO from biomass burning (BCwb and COwb, respectively) present a clear diurnal pattern, with the highest concentrations during night-time, supporting the theory of local domestic heating being their main source.

Gambaran Kadar HbCO dalam Darah pada Masyarakat Dusun Gemeling, Gedangan, Sidoarjo

Carbon monoxide (CO) is one of the toxic pollutants which is resulted from the emission of mobile sources and immovable sources. The inhaled CO will go into the lungs then into the bloodstrea. For instance, it will compete with oxygen to bind the hemoglobin. CO-hemoglobin bond forms hemoglobin carboxy (HbCO) which is 200-300 times stronger than the oxygen bond with Hb. As consequence, oxygen is pushed out from its bond with Hb. This study aims to determine the description of blood HbCO levels in the community of Demeling Hamlet due to CO exposure from roads located in Gedangan and cooking oil factory nearby.This research is descriptive research with cross sectional approach. Samples of HbCO in blood were taken from 12 housewives aas respondets who domiciled in Dusun Demeling and samples of CO in the air (5 points). Technique of sampling in this study used technique of Purposive Sampling. Data collected is analyzed using tabulation descriptively in the form of tables.The results showed that HbCO levels in the blood of respondents living nearby Gedangan had an average of 9.98% and respondents living close to the cooking oil factory with an average of 8.68%. Average of ambient CO levels in the air around Gedangan was 11456.04 μg / Nm3 and area near the cooking oil factory was 2063.07 μg / Nm3. Respondents aged &gt; 40 years had an average HbCO in blood of 11.54% and the age of ≤40 years had an average of 6.24%.Respondents living&gt; 5 years had an average HbCO of 9.34%. Respondents whose location near Gedangan roads had average HbCO levels higher than respondents near the cooking oil factory because motor vehicle activity lasts for 24 hours. At last, to reduce CO content in the ambient air, it is hoped that people can create green environment by planting plants around their house. Keywords : HbCO content, Carbon monoxide, Road

Garage carbon monoxide levels from sources commonly used in intentional poisoning.

The incidence of intentional carbon monoxide (CO) poisoning is believed to have declined due to strict federal CO emissions standards for motor vehicles and the uniform application of catalytic converters (CC). We sought to compare ambient CO levels produced by automobiles with and without catalytic converters in a residential garage, as well as from other CO sources commonly used for intentional poisoning. CO levels were measured inside a freestanding 73 m3 one-car garage. CO sources included a 1971 automobile without CC, 2003 automobile with CC, charcoal grill, electrical generator, lawn mower and leaf blower. After 20 minutes of operation, the CO level in the garage was 253 PPM for the car without a catalytic converter and 30 PPM for the car equipped withone. CO levels after operating or burning the other sources were: charcoal 200 PPM; generator >999 PPM; lawn mower 198 PPM; and leaf blower 580 PPM. While emissions controls on automobiles have reduced intentional CO poisonings, alternate sources may produce CO at levels of the same magnitude as vehicles manufactured prior to the use of catalytic converters. Those involved in the care of potentially suicidal individuals should be aware of this.

English

Increasing road congestion and high traffic volume is often times an indicator of atmospheric air pollution. Ibadan, being the largest metropolitan city in southwestern Nigeria, experiences steady influx of vehicular movement on daily bases. The situation is made worse as a greater number of these vehicles are old and poorly maintained. This study therefore investigated the likely impact of high traffic volume along a major roadway (the Ojoo-Mokola road) within the Ibadan metropolis on atmospheric air quality. Eight sampling points along a stretch of the roadway were identified for traffic density and air quality monitoring. Data was collected monthly over a period of four months in the morning peak, off peak and evening peak hours. Air quality parameters, carbon monoxide (CO), nitrogen dioxide (NO2), sulphur dioxide (SO2), hydrogen sulphide (H2S) and ammonia (NH3) were measured using handheld Crowcon Triple Plus+ and Crowcon Tetra-Portable Multi-Gas Detectors. The average concentration of CO range between 3.25 and 50.8 ppm with highest concentration observed during the morning and evening peak hours. There was a strong correlation (p=0.05) between ambient CO levels and traffic density. Relatively low levels of H2S, and NH3 were detected while NO2 levels were relatively constant (&lt;0.1 ppm). Sulphur dioxide was generally not detected within the study locations. Though this study did not cover the whole city of Ibadan, findings from the eight sampling points suggest that this major stretch of road may altogether not be safe from traffic related problems. There is need for constant monitoring of vehicular emissions to forestall possible air pollution. &nbsp; Key words: Air quality, vehicular emissions, traffic density, carbon dioxide.

Impact of carbon monoxide and nitrogen dioxide on cardiovascular biomarkers in the Study of Women's Health Across the Nation

Introduction: Impacts from ambient carbon monoxide (CO) and nitrogen dioxide (NO2) on cardiovascular disease (CVD) has been reported, but the biologic mechanisms connecting them remain uncertain. This study examined whether elevated ambient CO and NO2 levels related to levels of CVD markers in midlife women. Methods: Annual repeated measurements of ten CVD markers, including high-sensitivity C-reactive protein (hs-CRP), fibrinogen, Factor VIIc, tissue-type plasminogen activator antigen (tPA-ag), plasminogen activator inhibitor Type 1 (PAI-1), and lipoprotein markers, were obtained from 2,207 women from five racial/ethnic groups enrolled in 6 US cities for the longitudinal Study of Women’s Health Across the Nation (average 3.8 visits/woman, mean age: 51±3 years). CO and NO2 data were obtained from the USEPA and assigned to each woman based on proximity to her home address. Prior year, 6-month, 30-day, 7-day, and one-day exposures were calculated, and their associations with CVD markers were examined using longitudinal mixed-effects models. Results: Adjusting for site, race/ethnicity, education, menopause status, body mass index, smoking, and recent alcohol use, CO and NO2 exposures were positively associated with fibrinogen, PAI-1, and tPA-ag levels. For an interquartile increase of the 1-year average gas concentration, 0.68 ppm for CO and 13 ppb for NO2, PAI-1 level increased 35% (95% CI: 29%, 42%) and 71% (57%, 86%), respectively. The same increases in the 30-day average CO and NO2 concentration corresponded to 4.5% (2.6%, 6.5%) and 4.5% (2.0%, 7.0%) increases in fibrinogen level. Adjusting for long-term PM2.5 exposure, the impact of 1-year CO exposure on PAI-1 was reduced to 18% (12%, 25%), and the association between CO and tPA-ag was null, indicating that PM2.5 also contributed to variations in these CVD markers. Conclusions: CO and NO2 exposures may increase coagulation and thrombotic potential, and thus may increase risks of CVD in midlife women.

Effects of inhaled CO administration on acute lung injury in baboons with pneumococcal pneumonia.

Inhaled carbon monoxide (CO) gas has therapeutic potential for patients with acute respiratory distress syndrome if a safe, evidence-based dosing strategy and a ventilator-compatible CO delivery system can be developed. In this study, we used a clinically relevant baboon model of Streptococcus pneumoniae pneumonia to 1) test a novel, ventilator-compatible CO delivery system; 2) establish a safe and effective CO dosing regimen; and 3) investigate the local and systemic effects of CO therapy on inflammation and acute lung injury (ALI). Animals were inoculated with S. pneumoniae (10(8)-10(9) CFU) (n = 14) or saline vehicle (n = 5); in a subset with pneumonia (n = 5), we administered low-dose, inhaled CO gas (100-300 ppm × 60-90 min) at 0, 6, 24, and/or 48 h postinoculation and serially measured blood carboxyhemoglobin (COHb) levels. We found that CO inhalation at 200 ppm for 60 min is well tolerated and achieves a COHb of 6-8% with ambient CO levels ≤ 1 ppm. The COHb level measured at 20 min predicted the 60-min COHb level by the Coburn-Forster-Kane equation with high accuracy. Animals given inhaled CO + antibiotics displayed significantly less ALI at 8 days postinoculation compared with antibiotics alone. Inhaled CO was associated with activation of mitochondrial biogenesis in the lung and with augmentation of renal antioxidative programs. These data support the feasibility of safely delivering inhaled CO gas during mechanical ventilation and provide preliminary evidence that CO may accelerate the resolution of ALI in a clinically relevant nonhuman primate pneumonia model.

False Positive Rate of Carbon Monoxide Saturation by Pulse Oximetry of Emergency Department Patients

Symptoms of carbon monoxide (CO) poisoning are non-specific. Diagnosis requires suspicion of exposure, confirmed by measuring ambient CO levels or carboxyhemoglobin (COHb). An FDA-approved pulse oximeter (Rad-57) can measure CO saturation (S(pCO)). The device accuracy has implications for clinical decision-making. From April 1 to August 15, 2008, study personnel measured S(pCO) and documented demographic factors at time of clinical blood draw, in a convenience sample of 1,363 subjects presenting to the emergency department at Intermountain Medical Center, Murray, Utah. The technician then assayed COHb. COHb and S(pCO) values were compared by subject; false positive or negative values were defined as S(pCO) at least 3 percentage points greater or less than COHb level, reported by the manufacturer to be ± 1 SD in performance. In 1,363 subjects, 613 (45%) were male, 1,141 (84%) were light-skinned, 14 in shock, 4 with CO poisoning, and 122 (9%) met the criteria for a false positive value (range 3-19 percentage points), while 247 (18%) met the criteria for a false negative value (-13 to -3 percentage points). Risks for a false positive S(pCO) reading included being female and having a lower perfusion index. Methemoglobin, body temperature, and blood pressure also appear to influence the S(pCO) accuracy. There was variability among monitors, possibly related to technician technique, as rotation of monitors among technicians was not enforced. While the Rad-57 pulse oximeter functioned within the manufacturer's specifications, clinicians using the Rad-57 should expect some S(pCO) readings to be significantly higher or lower than COHb measurements, and should not use S(pCO) to direct triage or patient management. An elevated S(pCO) could broaden the diagnosis of CO poisoning in patients with non-specific symptoms. However, a negative S(pCO) level in patients suspected of having CO poisoning should never rule out CO poisoning, and should always be confirmed by COHb.

An analysis of asthma hospitalizations, air pollution, and weather conditions in Los Angeles County, California

There is now a large body of literature supporting a linkage between exposure to air pollutants and asthma morbidity. However, the extent and significance of this relationship varies considerably between pollutants, location, scale of analysis, and analysis methods. Our primary goal is to evaluate the relationship between asthma hospitalizations, levels of ambient air pollution, and weather conditions in Los Angeles (LA) County, California, an area with a historical record of heavy air pollution. County-wide measures of carbon monoxide (CO), nitrogen dioxide (NO2), ozone (O3), particulate matter<10μm (PM10), particulate matter<2.5μm (PM2.5), maximum temperature, and relative humidity were collected for all months from 2001 to 2008. We then related these variables to monthly asthma hospitalization rates using Bayesian regression models with temporal random effects. We evaluated model performance using a goodness of fit criterion and predictive ability. Asthma hospitalization rates in LA County decreased between 2001 and 2008. Traffic-related pollutants, CO and NO2, were significant and positively correlated with asthma hospitalizations. PM2.5 also had a positive, significant association with asthma hospitalizations. PM10, relative humidity, and maximum temperature produced mixed results, whereas O3 was non-significant in all models. Inclusion of temporal random effects satisfies statistical model assumptions, improves model fit, and yields increased predictive accuracy and precision compared to their non-temporal counterparts. Generally, pollution levels and asthma hospitalizations decreased during the 9year study period. Our findings also indicate that after accounting for seasonality in the data, asthma hospitalization rate has a significant positive relationship with ambient levels of CO, NO2, and PM2.5.

Determinants of In-Vehicle Exposure to Traffic-Induced Emissions

The past two decades have witnessed a growing concern about in-vehicle air quality with an emphasis on passenger cars, with greater levels of exposure to traffic-induced emissions recorded of all transport modes. In this study, in-vehicle exposure to carbon monoxide (CO) is examined under eight ventilation modes on a 2,333-m circuit in the Hamra–Bliss Area of Beirut, Lebanon, and the influence of ventilation mode, outdoor CO concentrations, and wind speed on in-vehicle exposure is assessed. The highest mean CO exposure was experienced for ventilation settings with the windows closed and vents closed and the windows closed and air conditioning on recirculation, with mean CO levels of 37.4 and 30.8 ppm, respectively, exceeding the 1-h air quality guidelines. In-vehicle CO levels revealed moderate to good correlation with out-of-vehicle CO levels for ventilation modes allowing outdoor air intake and no correlation with ambient CO levels and wind speed. A mass balance modeling with measured out-of-vehicle CO levels and a trip-specific movement record as boundary conditions ascertained a contribution to in-vehicle exposure of self-pollution, or the ingression of a vehicle's own engine fumes into the vehicle compartment.

Physiological fitness and health adaptations from purposeful training using off-road vehicles

The purpose of this study was to evaluate fitness and health adaptations from a training program riding all-terrain vehicles (ATV) and off-road motorcycles (ORM) as the exercise stimulus. Participants (n=58) were randomized to a control group (n=12) or one of four experimental groups; 2days/week ATV (n=11), 2days/week ORM (n=12), 4days/week ATV (n=11), or 4days/week ORM (n=12). Aerobic fitness, musculoskeletal fitness, body composition, clinical health, and quality of life (QOL) were compared at baseline and following 6weeks of training. In all riding groups, there were improvements in blood pressure (SBP=9.4±10.1, DBP=5.8±6.2mmHg), fasting glucose (0.5±0.7mmol/l), subcutaneous adiposity (0.9±1.1%), body mass (0.7±2.7kg), waist circumference (1.3±2.5cm), and isometric leg endurance (26±44s). All changes were of moderate to large magnitude (Cohen's d 0.52-0.94) with the exception of a small loss of body mass (Cohen's d=0.27). Although changes occurred in the riding groups for aerobic power (2.9±4.6mlkg(-1)min(-1)), leg power (172±486w), and curl-ups (13.2±22.7), these changes were not significantly different from the control group. No significant alterations occurred in resting heart rate, trunk flexibility, back endurance, hand grip strength, long jump, pull/push strength, or push-up ability as a result of training. Physical domain QOL increased in all 2days/week riders but mental domain QOL increased in all ORM, but not ATV riders regardless of volume. Ambient carbon monoxide levels while riding (<30ppm) were within safe exposure guidelines. Positive adaptations can be gained from a training program using off-road vehicle riding as the exercise stimulus.

Comparison of exhaled carbon monoxide levels among commuters and roadside vendors in an urban and a suburban population in Pakistan

Carbon monoxide (CO) is one of the six criteria air pollutants related to urbanization and has a wide range of health effects. The study measured and compared the exhaled CO levels among commuters and roadside vendors in potentially heavy and low traffic volume areas of Karachi, a megacity in Pakistan. Saddar town [areas of M. A. Jinnah Road (Tibet Center, Denso Hall) and Empress Market] was selected to represent an area of high traffic volume and the suburban town of Gadap (Gadap and Gulshan-e-Maymar) was selected to represent an area of no or low traffic volume. The study compared the CO exposure of commuters and roadside vendors in high and low traffic volume in Karachi. CO exposure was measured in expired air using the breath analyzer module of Bacharach Monoxor-II, USA. A total of 326 individuals (115 commuters and 211 stationary roadside vendors) from Saddar town (n = 193) and Gadap town (n = 133) were selected. In addition, CO levels in ambient air in the same areas, using portable CO analyzer (Bacharach, Monoxor-II, USA), were measured. The mean ambient CO level at Saddar town was 15.6 (SE ± 2.6) ppm compared to 3.3 (SE ± 0.3) ppm at Gadap town. The mean CO level in expired air was significantly higher among nonsmokers at Saddar town (12.8 ± 0.5 ppm) compared to the nonsmokers at Gadap town (7.8 ± 0.4 ppm). The mean CO level in expired air among smokers was twice that of nonsmokers (21.6 vs. 10.6 ppm). CO in expired air was greater among high traffic volume commuters and roadside stationary population in Karachi, Pakistan. The population in Karachi is exposed to high concentration of air pollutants. These pollutants need to be characterized for health effects and interventions needs to be developed.

Factors affecting exhaled carbon monoxide levels in coffeehouses in the Western Black Sea region of Turkey

The aim of this study was to evaluate indoor air quality and factors affecting expired carbon monoxide (CO) levels in a coffeehouse environment. This cross-sectional study was conducted at 16 randomly selected coffeehouses in Duzce, Turkey, during November 2007 to March 2008. A total of 547 people, average age 46.72 ± 17.03 (19-82) years, participated. The selected coffeehouses were divided into four groups: (1) smoking, (2) nonsmoking, (3) old-style and (iv) new-style coffeehouses. Prior to entering the coffeehouse, exhaled CO levels in smokers (mean 21.17 ± 6.73 parts per million [ppm]) were significantly higher than those for nonsmokers (6.51 ± 4.56 ppm; p < 0.001). Measurements taken after 2 hours in the coffeehouse also showed significantly higher CO concentrations for smokers (22.72 ± 5.31 ppm), compared to nonsmokers (6.51 ± 4.56 ppm; p < 0.001). It was determined that CO levels inside coffee shops were above the WHO guidelines. Exhaled CO levels in nonsmokers are influenced by the ambient CO levels as a result of the use of cigarettes in coffeehouses in addition to the structure of coffeehouses.

Personal Exposure of Traffic Police Officers to Particulate Matter, Carbon Monoxide, and Benzene in the City of Milan, Italy

The aim of this work was to quantify the personal exposure of traffic police officers to particulate matter (PM), carbon monoxide (CO), benzene, toluene, ethylbenzene, and xylenes. The contributions of some behavioral, occupational, and meteorological determinants of exposure also were evaluated. Personal exposure to airborne contaminants was measured on 130 selected volunteers in four seasonal sampling sessions. CO was measured with high sampling frequency. A time-activity diary was completed by traffic police officers during their work shift. Mean (median) personal exposure levels of carbon monoxide, respirable particles (PM resp ), and benzene were 3.51 (3.22) mg/m3, 128 (115) μ g/m3 and 11.5 (9.6) μ g/m3, respectively. The highest ambient mean levels of PM resp , CO, and benzene were found during cold seasons. Measurements taken where traffic is directed, schools are guarded, and other outdoor tasks are performed showed the highest median CO concentrations. As expected, wind decreased exposure to CO and benzene. Exposure was not significantly affected by active tobacco smoke. A key finding was that airborne concentrations determined by fixed measurement stations reported in other studies greatly underestimated traffic officers' exposure to airborne contaminants. The proximity to an emission source determined by the occupational activity was the factor that most affected exposure. For this reason, fixed stations are poor predictors of roadside exposures to airborne pollutants.

Ambient Air Pollution and Birth Weight in Full-Term Infants in Atlanta, 1994-2004

ISEE-0430 Background and Objective: An emerging body of evidence suggests ambient levels of air pollution during pregnancy are associated with fetal growth. Methods: We used vital records data to construct a retrospective cohort of 406,627 full-term births occurring between 1994 and 2004 in five central counties of metropolitan Atlanta, USA. We examined the relationship between birth weight and temporal variation in ambient levels of carbon monoxide (CO), nitrogen dioxide (NO2), sulfur dioxide (SO2), ozone (O3), PM10 (particulate matter <10 μm in diameter), PM2.5 (particulate matter <2.5 μm in diameter) and speciated PM2.5 measurements. Daily pollutant levels in five-county Atlanta were characterized using a population-weighted spatial average of air quality monitors in the study area. Daily concentrations were then averaged over the time period corresponding to each infant's third trimester. We also conducted capture-area analyses limited to mothers residing within four miles (6.4 km) of each air quality monitoring station. Linear regression models included control for seasonal and long-term time trends, gestational week, maternal education, maternal marital status, maternal age, maternal tobacco use, race and ethnicity, and parity. Results: In the five-county analysis, ambient levels of NO2, SO2, PM2.5 elemental carbon and PM2.5 water-soluble metals were significantly associated with small reductions in birth weight in full-term infants (−4 to −16 grams per interquartile range [IQR] increase in pollutant concentrations). The capture-area analyses provided little evidence of harmful effects of air pollution, but confidence intervals were wide. Conclusion: Results provide limited support for an effect of ambient air pollution in the third trimester on birth weight in full-term infants.

Ambient air pollution and preterm birth: a time-series analysis.

An emerging body of evidence suggests that ambient levels of air pollution during pregnancy are associated with preterm birth. To further investigate these relationships we used vital record data to construct a retrospective cohort of 476,489 births occurring between 1994 and 2004 in 5 central counties of metropolitan Atlanta. Using a time-series approach, we examined aggregated daily counts of preterm birth in relation to ambient levels of carbon monoxide, nitrogen dioxide, sulfur dioxide, ozone, particulate matter <10 microm in diameter (PM10), particulate matter <2.5 microm in diameter (PM2.5), and speciated PM measurements. Daily pollutant levels in 5-county Atlanta were characterized using a population-weighted spatial average of air quality monitors in the study area. We also examined ambient concentrations at individual monitors in analyses limited to mothers with residential geocodes within 4 miles of each monitor. Relationships between average pollution levels during 3 gestational windows of interest were modeled using Poisson generalized linear models. Results were adjusted for seasonal and long-term time trends. Although most results were null, there were 3 positive associations between ambient pollution levels and preterm birth in the 4-mile capture-area analyses. Daily preterm birth rates were associated with average NO2 concentrations in the preceding 6 weeks and with average PM2.5 sulfate and PM2.5 water-soluble metal concentrations in the preceding week. Results provide limited support for late-pregnancy effects of ambient air pollution on preterm birth.

Emergency Hospital Admissions for Cardiovascular Diseases and Ambient Levels of Carbon Monoxide

Evidence on risk of cardiovascular disease (CVD) hospitalization associated with short-term exposure to outdoor carbon monoxide (CO), an air pollutant primarily generated by traffic, is inconsistent across studies. Uncertainties remain on the degree to which associations are attributable to other traffic pollutants and whether effects persist at low levels. We conducted a multisite time-series study to estimate risk of CVD hospitalization associated with short-term CO exposure in 126 US urban counties during 1999-2005 for >9.3 million Medicare enrollees aged > or =65 years. We considered models with adjustment by other traffic-related pollutants: NO2, fine particulate matter (with aerodynamic diameter < or =2.5 microm), and elemental carbon. We found a positive and statistically significant association between same-day CO and increased risk of hospitalization for multiple CVD outcomes (ischemic heart disease, heart rhythm disturbances, heart failure, cerebrovascular disease, total CVD). The association remained positive and statistically significant but was attenuated with copollutant adjustment, especially NO2. A 1-ppm increase in same-day daily 1-hour maximum CO was associated with a 0.96% (95% posterior interval, 0.79%, 1.12%) increase in risk of CVD admissions. With same-day NO(2) adjustment, this estimate was 0.55% (0.36%, 0.74%). The risk persisted at low CO levels <1 ppm. We found evidence of an association between short-term exposure to ambient CO and risk of CVD hospitalizations, even at levels well below current US health-based regulatory standards. This evidence indicates that exposure to current CO levels may still pose a public health threat, particularly for persons with CVD.

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 intoxication: An updated review

Carbon monoxide (CO), a highly toxic gas produced by incomplete combustion of hydrocarbons, is a relatively common cause of human injury. Human toxicity is often overlooked because CO is tasteless and odorless and its clinical symptoms and signs are non specific. The brain and the heart may be severely affected after CO exposure with carboxyhemoglobin (COHb) levels exceeding 20%. Damage occurs because the affinity of hemoglobin for CO is 210 times higher than for O(2). Hypoxic brain damage predominates in the cerebral cortex, cerebral white matter and basal ganglia, especially in the globus pallidus. Diagnosis requires clinical acumen and a high index of suspicion, combined with epidemiological data, clinical examination, analysis of ambient air CO and patient COHb levels; also required are cardiology evaluation including ECG as well as neurological evaluation including brain imaging (CT and/or MRI, MR spectroscopy), and neuropsychological testing. Although immediate O(2) breathing is sometimes an adequate treatment, hyperbaric oxygen therapy (HBO) is favored. Subsequently, only symptomatic therapy is available for the long-term sequelae of CO poisoning.

The effect of different ventilation modes on in-vehicle carbon monoxide exposure

In-vehicle carbon monoxide (CO) concentration profiles were monitored in a passenger vehicle driven along a heavily traveled route of a commercial/residential area of Beirut, Lebanon, under several ventilation modes. Trips were conducted during morning rush hours in spring and summer time. Concomitant monitoring of car-exterior CO level, ambient CO level and wind speed was also undertaken. The highest mean CO exposure was experienced for the “windows closed, vents closed” and “windows closed, AC on recirculation” ventilation settings, with mean CO levels of 37.4 and 30.8 ppm, respectively, exceeding the 1-h air quality guidelines. The exposure was less significant for other ventilation modes with respective mean values of 10.8 – 19 ppm . Mean car-exterior CO levels were lower than the 1-h air quality guidelines, but exceeded the 8-h CO exposure guidelines. Ambient CO levels were low and non-representative of the personal exposure of individuals neither inside nor in the vicinity of road vehicles. In-vehicle CO levels revealed moderate to good correlations to out-vehicle CO levels for ventilation modes allowing for outdoor air intake, and no correlation to ambient CO levels and wind speed. Infiltration as a result of indoor–outdoor air exchange and intrusion from engine combustion/exhaust infiltration constituted the main sources of observed in-vehicle CO levels.