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PubMedDate not supplied

An air pollution model for use in epidemiological studies: evaluation with measured levels of nitrogen dioxide and benzene.

The aim of the study was to evaluate the predictions derived from the Danish Operational Street Pollution Model (OSPM) when the input data are obtained by simple methods that could be used in large-scale epidemiological studies. The model calculations were thus compared with passive sampler measurements of nitrogen dioxide and benzene at 103 street locations in Copenhagen, Denmark, and at 101 locations in rural areas. Data on traffic and street configuration were collected by means of a simple registration scheme in which forms were filled out by local municipal authorities. Meteorological data were derived from routine measurements at Copenhagen airport, and data on background air pollution were based on a simple empirical model. Differences in air pollution levels between rural areas and Copenhagen and differences in nitrogen dioxide concentrations at various locations in Copenhagen were well reproduced by the OSPM. The correlation coefficients (r) between the measured and the predicted half-year average concentrations of nitrogen dioxide in Copenhagen were between 0.75 and 0.80 for various degrees of precision of the input data for the model. The results indicate that the OSPM used with the presented methods for generation of input data might be useful in assessing long-term exposure to air pollutants in epidemiological studies.

Air Pollution↗
PubMed2006

Association between maternal exposure to ambient air pollutants during pregnancy and fetal growth restriction.

Previous research demonstrated consistent associations between ambient air pollution and emergency room visits, hospitalizations, and mortality. Effect of air pollution on perinatal outcomes has recently drawn more attention. We examined the association between intrauterine growth restriction (IUGR) among singleton term live births and sulfur dioxide (SO2), nitrogen dioxide (NO2), carbon monoxide (CO), ozone (O3), and fine particles (PM2.5) present in ambient air in the Canadian cities of Calgary, Edmonton, and Montreal for the period 1985-2000. Multiple logistic regression was used to estimate odds ratios (ORs) and 95% confidence intervals (CIs) for IUGR, based on average daily levels of individual pollutants over each month and trimester of pregnancy after adjustment for maternal age, parity, infant gender, season, and city of residence. A 1 ppm increase in CO was associated with an increased risk of IUGR in the first (OR=1.18; 95% CI 1.14-1.23), second (OR=1.15; 95% CI 1.10-1.19) and third (OR=1.19; 95% CI 1.14-1.24) trimesters of pregnancy, respectively. A 20 ppb increase in NO2 (OR=1.16; 95% CI 1.09-1.24; OR=1.14; 95% CI 1.06--1.21; and OR=1.16; 95% CI 1.09-1.24 in the first, second, and third trimesters) and a 10 mug/m3 increase in PM2.5 (OR=1.07; 95% CI 1.03-1.10; OR=1.06; 95% CI 1.03-1.10; and OR=1.06; 95% CI 1.03-1.10) were also associated with an increased risk of IUGR. Consistent results were found when ORs were calculated by month rather than trimester of pregnancy. Our findings add to the emerging body of evidence that exposure to relatively low levels of ambient air pollutants in urban areas during pregnancy is associated with adverse effects on fetal growth.

Air Pollutants↗
PubMed1999

Gaseous air pollution and atopy.

BACKGROUND: Photochemical air pollutants are commonly thought to be implicated in the gradual increase in the prevalence of atopy. However, no epidemiological data are available. METHODS: To clarify this issue, we performed a cross-sectional epidemiological survey in 2604 primary school children, 10 and 11 years old, living in seven communities among which some have the highest photochemical exposure in France. The mean levels of the main gaseous air pollutants (SO2, NO2 and O3) were measured during a 2-month period in 1993. The protocol included a standardized questionnaire, skin prick tests to common aeroallergens and in the atopic children, collection of a sample of mattress dust to measure group 1 mite allergens. Atopy was only defined on the basis of the skin prick tests. RESULTS: Percentage of positive skin tests and the number of positive skin tests were similar in the different communities looked at. The distribution of dust samples with a group 1 allergen level greater than 2 microg/g dust, was also similar. Logistic regression analysis including potential confounding factors, as well as the mean level of air pollutants, did not demonstrate any association between atopy and mean SO2, NO2 and O3 levels. CONCLUSION: The increase in photochemical air pollutants is unlikely to be a major determinant for the recent increase in the prevalence of atopy.

Air Pollutants↗
PubMed2004

The effect of air pollution on lung development from 10 to 18 years of age.

BACKGROUND: Whether exposure to air pollution adversely affects the growth of lung function during the period of rapid lung development that occurs between the ages of 10 and 18 years is unknown. METHODS: In this prospective study, we recruited 1759 children (average age, 10 years) from schools in 12 southern California communities and measured lung function annually for eight years. The rate of attrition was approximately 10 percent per year. The communities represented a wide range of ambient exposures to ozone, acid vapor, nitrogen dioxide, and particulate matter. Linear regression was used to examine the relationship of air pollution to the forced expiratory volume in one second (FEV(1)) and other spirometric measures. RESULTS: Over the eight-year period, deficits in the growth of FEV(1) were associated with exposure to nitrogen dioxide (P=0.005), acid vapor (P=0.004), particulate matter with an aerodynamic diameter of less than 2.5 microm (PM(2.5)) (P=0.04), and elemental carbon (P=0.007), even after adjustment for several potential confounders and effect modifiers. Associations were also observed for other spirometric measures. Exposure to pollutants was associated with clinically and statistically significant deficits in the FEV(1) attained at the age of 18 years. For example, the estimated proportion of 18-year-old subjects with a low FEV(1) (defined as a ratio of observed to expected FEV(1) of less than 80 percent) was 4.9 times as great at the highest level of exposure to PM(2.5) as at the lowest level of exposure (7.9 percent vs. 1.6 percent, P=0.002). CONCLUSIONS: The results of this study indicate that current levels of air pollution have chronic, adverse effects on lung development in children from the age of 10 to 18 years, leading to clinically significant deficits in attained FEV(1) as children reach adulthood.

Adolescent↗
PubMed2003

The burden of disease from indoor air pollution in developing countries: comparison of estimates.

Four different methods have been applied to estimate the burden of disease due to indoor air pollution from household solid fuel use in developing countries (LDCs). The largest number of estimates involves applying exposure-response information from urban ambient air pollution studies to estimate indoor exposure concentrations of particulate air pollution. Another approach is to construct child survival curves using the results of large-scale household surveys, as has been done for India. A third approach involves cross-national analyses of child survival and household fuel use. The fourth method, referred to as the 'fuel-based' approach, which is explored in more depth here, involves applying relative risk estimates from epidemiological studies that use exposure surrogates, such as fuel type, to estimates of household solid fuel use to determine population attributable fractions by disease and age group. With this method and conservative assumptions about relative risks, 4-5 percent of the global LDC totals for both deaths and DALYs (disability adjusted life years) from acute respiratory infections, chronic obstructive pulmonary disease, tuberculosis, asthma, lung cancer, ischaemic heart disease, and blindness can be attributed to solid fuel use in developing countries. Acute respiratory infections in children under five years of age are the largest single category of deaths (64%) and DALYs (81%) from indoor air pollution, apparently being responsible globally for about 1.2 million premature deaths annually in the early 1990s.

Air Pollutants↗
PubMedDate not supplied

The role of intercellular adhesion molecule-1 (ICAM-1), vascular cell adhesion molecule-1 (VCAM-1), and regulated on activation, normal T-cell expressed and secreted (RANTES) in the relationship between air pollution and asthma among children.

To evaluate the role of adhesion molecules and chemokines in the relationship between air pollution and asthma, the authors determined the following in 230 children who lived in 4 communities in Japan that had different levels of air pollution: serum concentrations of soluble intercellular adhesion molecule-1 (sICAM-1); soluble vascular cell adhesion molecule-1 (sVCAM-1); regulated on activation, normal T-cell expressed and secreted (RANTES); and total immunoglobulin E (IgE). Children with asthma or who exhibited wheezing (n = 115) and nonasthmatic children (n = 115) were studied. Serum concentrations of sICAM-1, sVCAM-1, and RANTES were increased significantly in asthmatic children, compared with nonasthmatic children. Nonasthmatic children with serum IgE levels that were greater than or equal to 250 IU/ml had significantly lower concentrations of sICAM-1 and sVCAM-1 than the other children. The geometric means of sICAM-1 increased as air pollution increased. The results of this study suggest that adhesion molecules or chemokines are associated with asthma and that ICAM-1 may play an important role in the relationship between air pollution and the occurrence of asthma.

Air Pollutants↗
PubMedDate not supplied

Acute asthma exacerbations and air pollutants in children living in Belfast, Northern Ireland.

The incidence of childhood asthma, a common condition, is on the rise worldwide. Despite reductions in the emission of urban smoke, traffic pollution is now a major worldwide problem. Belfast, Northern Ireland, is an old industrial city with major pollution problems. In this study, the authors investigated the rates of acute asthma admissions to Belfast's major children's emergency department. The admissions were studied, relative to day-to-day fluctuations in thoracic particulate matter, sulfur dioxide, nitrogen dioxide, nitric oxide, oxides of nitrogen, ozone, carbon monoxide, benzene, temperature, and rainfall. Daily admissions for acute asthma at the emergency department of the Royal Belfast Hospital and average daily pollution were recorded for the 3-yr period between January 1, 1993, and December 31, 1995. The authors used Poisson regression to assess independent association(s). Individually, small associations were seen for thoracic particulate matter (relative risk = 1.10), sulfur dioxide (relative risk = 1.09), nitrogen dioxide (relative risk = 1.11), nitric oxide (relative risk = 1.07), oxides of nitrogen (relative risk = 1.10), carbon monoxide (relative risk = 1.07), and benzene (1.14); no associations were noted between meteorological factors (temperature and rainfall) or ozone and asthma emergency-department admissions. The authors adjusted for the aforementioned parameters, and benzene level was the only variable associated independently with asthma emergency-department admissions in children. Benzene may be a more reliable method of measuring exposure to vehicle exhaust emissions than measurements of other pollutants.

Acute Disease↗
PubMedDate not supplied

Assessment of physical education time and after-school outdoor time in elementary and middle school students in south Mexico City: the dilemma between physical fitness and the adverse health effects of outdoor pollutant exposure.

Strategies to promote lifelong physical activity among children are needed to stem the adverse health consequences of inactivity. However, the health effects in growing children of long-term exposure to a polluted atmosphere are of deep concern. The atmosphere of south Mexico City (SMC) is characterized by a complex mixture of air pollutants, including ozone, particulate matter, and aldehydes. Radiological evidence suggests that small-airway disease could be present in clinically healthy, tobacco unexposed SMC children. The aim of this study was to assess, by means of a self-reported questionnaire, the physical education class times, daily outdoor after-school exposure time, and tobacco exposure in students attending public elementary and middle schools in SMC. Additionally, the time each student spent viewing television was assessed, and the authors measured each student's weight and height to determine body mass index (BMI, weight in kg divided by height in m2). The survey included 1,159 students in grades 7-9. The authors identified 2 critical periods of outdoor exposure in SMC children that coincided with significant concentrations of both ozone and particulate matter with diameters less than 10 micrometers (PM10): during school time after 11:00 A.M. and in the after-school outdoor activity period, usually extending from 1:00 P.M. to 6:00 P.M. Thirty-two percent of elementary and 61% of middle school students have physical education classes after 11:00 A.M. Students in SMC spend an average of 19.6 hr/wk outdoors in the after-school period, during which time they are engaged in light to moderate physical activities. Half of the students are exposed to tobacco smoke at home, and 7% of middle school students smoke. On the basis of BMI, 60% of students were classified as undernourished, overweight, or obese. No correlations were found between BMI and time spent viewing TV, time outdoors (on weekdays and weekends), or exposure to environmental tobacco smoke. Children and adolescents in SMC are participating in physical activities that enhance multiple components of health-related fitness. However, their activities occur outdoors, where they are exposed to high concentrations of air pollutants throughout the year. The authors believe that SMC children and adolescents must be educated, through both the school and health systems, regarding ways to obtain the necessary exercise while protecting themselves from the high concentrations of pollutants. Individuals should instruct and encourage young people to be involved in lifetime fitness activities and to eat balanced diets, if the goal is to control health-care costs, reduce disease incidence, and improve the overall quality of life of the Mexico City population.

Adolescent↗
PubMedDate not supplied

Mortality from asthma and chronic bronchitis associated with changes in sulfur oxides air pollution.

Death certificates issued in Yokkaichi, Japan, during the 21 yr from 1963 until 1983 were surveyed to determine the relationship between changes in air pollution and mortality due to bronchial asthma and chronic bronchitis. The following results were obtained. In response to worsening air pollution, mortality for bronchial asthma and chronic bronchitis began to increase. Mortality due to bronchial asthma decreased immediately in response to improvement of pollution, whereas mortality due to chronic bronchitis decreased to the level in the control area 4 to 5 yr after the concentration of sulfur dioxide (SO2) began to satisfy the ambient air quality standard. In the polluted area, mortality due to bronchial asthma in subjects who were 20 yr of age was higher during the period in which higher concentrations of sulfur oxides were prevalent.

Adolescent↗
PubMedDate not supplied

The association of air pollution and mortality: examining the case for inference.

An association between air pollution measured as particulate matter, and mortality has been reported in several different locations. These studies have been conducted over a wide range of climates and populations. The time-series studies, which examine the joint occurrence of daily fluctuations in air pollution and mortality, provide the strongest evidence of a true association. However, several criteria, including the consistency of the results, need to be explored before causality is inferred from these studies. A striking consistency in the results was observed, after the different studies were converted into a common metric. The mean effect of an 10 micrograms/m3 change in PM10 implied by these studies varies between 0.64 and 1.49%. The fulfillment of other criteria, including specificity, presence of a dose-response relationship, and coherence of results, lend strong support to the existence of an actual association between particulate matter and mortality. However, the biologic mechanism is not well understood at this time. In addition, the precise measure of the pollutant responsible for the health effect--total suspended particles, PM10, fine particles, sulfates, acidic aerosols, sulfur dioxide, or some as yet unmeasured pollutant--is unclear, based on current available evidence.

Air Pollutants↗
PubMedDate not supplied

Why do estimates of the acute and chronic effects of air pollution on mortality differ?

Several investigators have discussed various reasons for the large and consistent difference in the relative risk estimates per unit exposure to air pollution derived from time-series and cohort study designs. This article considers whether the two study designs are estimating fundamentally different parameters even though both are commonly expressed in terms of relative risk coefficients. A frailty model for air pollution mortality is proposed to illustrate some of the theoretical behaviors of heterogeneous populations exposed to time-varying pollution patterns and their implications for the kinds of summary measures widely used in air pollution risk assessment.

Air Pollutants↗
PubMed1978

A chemical adsorption system for the sampling of gaseous organic pollutants in operating theatre atmospheres.

The development of an air sampler and its use in measuring organic pollutants in operating theatre atmospheres are described. Air was sampled continuously during an operating session and the results obtained represent the average pollution at the sample site during that session. The technique involved the chemical adsorption of organic vapours to polymer beads and pollutants thus trapped could be stored for several days before thermal desorption and analysis by gas chromatography. The three most abundant organic pollutants were ethanol, propan-2-ol (isopropanol) and halothane.

Adsorption↗
PubMed1980

Comparison of personal pollution monitoring techniques for use in the operating room.

Three personal pollution monitors (adsorption tubes, diffusion dosimeters and evacuated bottles) have been tested, in routinely used operating rooms and under controlled laboratory conditions, for their accuracy and reproducibility relative to one another and to measurements by infra-red spectroscopy. All the techniques provide time-weighted average measurements of pollutant concentrations. Tubes and dosimeters measure halothane with greater accuracy than that required by N.I.O.S.H. regulations, but neither technique can measure inorganic pollutants such as nitrous oxide. The prototype evacuated bottles tested are unsatisfactory at their present stage of development for the measurement of both halothane and nitrous oxide concentrations. We believe that, at the present time, surveys of operating room pollution can best be carried out using adsorption tubes of diffusion dosimeters for personal halothane concentrations and a portable infra-red spectrometer for measurement of background nitrous oxide concentrations.

Adsorption↗
PubMed1998

Indoor biofuel air pollution and respiratory health: the role of confounding factors among women in highland Guatemala.

BACKGROUND: A number of studies have reported associations between indoor biofuel air pollution in developing countries and chronic obstructive lung disease (COLD) in adults and acute lower respiratory infection (ALRI) in children. Most of these studies have used indirect measures of exposure and generally dealt inadequately with confounding. More reliable, quantified information about this presumed effect is an important pre-requisite for prevention, not least because of the technical, economic and cultural barriers to achieving substantial exposure reductions in the world's poorest households, where ambient pollution levels are typically between ten and a hundred times higher than recommended standards. This study was carried out as part of a programme of research designed to inform the development of intervention studies capable of providing quantified estimates of health benefits. METHODS: The association between respiratory symptoms and the use of open fires and chimney woodstoves ('planchas'), and the distribution of confounding factors, were examined in a cross-sectional study of 340 women aged 15-45 years, living in a poor rural area in the western highlands of Guatemala. RESULTS: The prevalence of reported cough and phlegm was significantly higher for three of six symptom measures among women using open fires. Although this finding is consistent with a number of other studies, none has systematically examined the extent to which strong associations with confounding variables in these settings limit the ability of observational studies to define the effect of indoor air pollution adequately. Very strong associations (P < 0.0001) were found between the type of fire and a number of household and socioeconomic factors including the arrangement of rooms, floor type, and possession of a radio and television. The spouse's economic activity type was also significantly associated (P < 0.05). Thus, while 82% of open fire users had dirt floors and only 18% cement or tile floors, the situation was reversed for plancha users, only 16% of whom had dirt floors. CONCLUSIONS: Confounding presents a substantial problem for observational studies of indoor air pollution and health, although there is a reasonable case for believing that the observed association is causal. Intervention studies are required for stronger evidence of this association, and more importantly, to determine the size of health benefit achievable through feasible exposure reductions.

Adolescent↗
PubMed2000

Patients with chronic obstructive pulmonary disease are at increased risk of death associated with urban particle air pollution: a case-crossover analysis.

The authors assessed the acute association between particulate air pollution and mortality among subjects suffering from chronic obstructive pulmonary disease by using a case-crossover analysis. This design avoided the common concerns about the methods used to assess the acute effects of air pollution. The 1,845 men and the 460 women included were residents of Barcelona, Spain, who were over age 35 years, had died during the period 1990-1995, and had visited emergency rooms because of a chronic obstructive pulmonary disease exacerbation during the period 1985-1989. Particle levels (measured as black smoke at the city monitoring stations) were associated with mortality for all causes (odds ratio (OR) for an increase of 20 microg/m3, the interquartile change, adjusted for temperature, humidity, and influenza = 1.112, 95 percent confidence interval (CI): 1.017, 1.215). The association was stronger for respiratory causes (OR = 1.182, 95 percent CI: 1.025, 1.365), but was not significant for cardiovascular causes (OR = 1.077, 95 percent CI: 0.917, 1.264). Older women, patients admitted to intensive care units, and patients with a higher rate of emergency room visits were at greater risk of dying associated with black smoke. The results reinforced the deleterious role of urban pollution and provided information on factors possibly conferring susceptibility to the acute role of air pollution.

Adult↗
PubMed1995

The association of ambient air pollution with twice daily peak expiratory flow rate measurements in children.

A stratified sample of 83 children living in Uniontown, Pennsylvania, reported twice daily peak expiratory flow rate (PEFR) measurements on 3,582 child-days during the summer of 1990. Upon arising and before retiring, each child recorded the time, three PEFR measurements, and the presence of cold, cough, or wheeze symptoms. Ambient air pollution, including particle-strong acidity, was measured separately during the day (8 a.m. to 8 p.m.) and at night. Each child's maximum PEFR for each session was expressed as the deviation from his or her mean PEFR over the study and adjusted to a standard of 300 liters/minute. The session-specific average deviation was then calculated across all of the children. A second-order autoregressive model for PEFR was developed, which included a separate intercept for evening measurements, trend, temperature, and 12-hour average air pollutant concentration weighted by the number of hours each child spent outdoors during the previous 12-hour period. The results are expressed in terms of the interquartile range for each pollutant. A 12-hour exposure to a 125-nmol/m3 increment in particle-strong acidity was associated with a -2.5 liters/minute deviation in the group mean PEFR (95% confidence interval (CI) -4.2 to -0.8) and with increased cough incidence (odds ratio (OR) = 1.6, 95% CI 1.1 to 2.4). A 30-ppb increment in ozone for 12 hours was associated with a similar deviation in PEFR levels (-2.8, 95% CI -67 to 1.1). The association between PEFR and particle-strong acidity was observed among the 60 children who were reported as symptomatic on the prior symptom questionnaire (-2.5, 95% CI -4.5 to -0.5). The authors conclude that summer occurrences of excessive acid aerosol and particulate pollution are associated with declines in peak expiratory flow rates in children.

Aerosols↗
PubMed1995

Air pollution and daily mortality in Philadelphia.

Many recent analyses have reported associations between air pollution and mortality in U.S. cities. In this paper, we present the results of regression analyses of daily mortality in Philadelphia during the period 1973-1988. Pollution variables included in the analyses were total suspended particulates (TSP), sulfur dioxide, and ozone. We controlled for the effects of weather on mortality by analyzing mortality separately for each season and explicityly including quintiles of temperature in the regression models. In regression models that consider weather and pollution variables simultaneously, daily mortality is associated with hot days in summer [relative risk (RR) for highest quintile of temperature = 1.07; 95% confidence interval (CI) = 1.04-1.10], and with cold days in spring (RR for lowest quintile of temperature = 1.07; 95% CI = 1.04-1.10), fall (RR for lowest quintile of temperature = 1.05; 95% CI = 1.02-1.08), and winter (RR for lowest quintile of temperature = 1.04; 95% CI = 1.01-1.07). When all three pollution covariates and weather are considered simultaneously in the regression model, ozone is associated with mortality in summer (RR = 1.15; 95% CI = 1.07-1.24) and sulfur dioxide is associated with mortality in spring (RR = 1.19; 95% CI = 1.06-1.33), fall (RR = 1.14; 95% CI = 1.00-1.29), and winter (RR = 1.21; 95% CI = 1.09-1.35), where the relative risks are for incremental changes of 100 parts per billion in ozone and sulfur dioxide on the previous day.(ABSTRACT TRUNCATED AT 250 WORDS)

Air Pollutants↗
PubMed2000

Air pollution and incidence of cardiac arrhythmia.

Air pollution episodes have been associated with increased cardiovascular hospital admissions and mortality in time-series studies. We tested the hypothesis that patients with implanted cardioverter defibrillators experience potentially life-threatening arrhythmias after such air pollution episodes. We compared defibrillator discharge interventions among 100 patients with such devices in eastern Massachusetts, according to variations in concentrations of particulate matter, black carbon, and gaseous air pollutants that were measured daily for the years 1995 through 1997. A 26-ppb increase in nitrogen dioxide was associated with increased defibrillator interventions 2 days later (odds ratio = 1.8; 95% confidence interval = 1.1-2.9). Patients with ten or more interventions experienced increased arrhythmias in association with nitrogen dioxide, carbon monoxide, black carbon, and fine particle mass. These results suggest that elevated levels air pollutants are associated with potentially life-threatening arrhythmia leading to therapeutic interventions by an implanted cardioverter defibrillator.

Adult↗