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1.
A South Australian preschool study carried out in 1993 showed that the prevalence of respiratory symptoms was significantly associated with use of unflued gas appliances for cooking and heating. The authors sought to determine an association between domestic exposure to nitrogen dioxide and the excretion of total urinary nitrate and nitrite and their association with asthma prevalence. The results indicated that the geometric mean concentrations of nitrogen dioxide were much higher in homes that had natural gas appliance(s) and other types of appliances (i.e., electric and solid fuel). Higher levels of nitrogen dioxide were found in homes of suburban areas with higher prevalence of asthma and respiratory symptoms. Nitrogen dioxide levels were lower in the summer and there was a higher level in kitchens than in bedrooms. Urinary nitrate excretion was evaluated in 1,335 preschool children from the same sampling areas. No association existed between nitrogen dioxide levels and urinary nitrates, nor was there a relationship between urinary nitrates and asthma prevalence. These findings confirm that there is a positive association between nitrogen dioxide exposure from gas appliances and the prevalence of respiratory symptoms, but urinary nitrate is not a useful biomarker of exposure at these levels.  相似文献   

2.
A South Australian preschool study carried out in 1993 showed that the prevalence of respiratory symptoms was significantly associated with use of unflued gas appliances for cooking and heating. The authors sought to determine an association between domestic exposure to nitrogen dioxide and the excretion of total urinary nitrate and nitrite, and their association with asthma prevalence. The results indicated that the geometric mean concentrations of nitrogen dioxide were much higher in homes that had natural gas appliance(s) and other types of appliances (i.e., electric and solid fuel). Higher levels of nitrogen dioxide were found in homes of suburban areas with higher prevalence of asthma and respiratory symptoms. Nitrogen dioxide levels were lower in the summer, and there was a higher level in kitchens than in bedrooms. Urinary nitrate excretion was evaluated in 1,335 preschool children from the same sampling areas. No association existed between nitrogen dioxide levels and urinary nitrates, nor was there a relationship between urinary nitrates and asthma prevalence. These findings confirm that there is a positive association between nitrogen dioxide exposure from gas appliances and the prevalence of respiratory symptoms, but urinary nitrate is not a useful biomarker of exposure at these levels.  相似文献   

3.
BACKGROUND: Effects of nitrogen dioxide (NO2) on respiratory health have been the subject of extensive research. The outcomes of these studies were not consistent. Exposure to nitrous acid, which is a primary product of combustion, and is also formed when NO2 reacts with water, may play an important role in respiratory health. We estimate the independent effects of exposure to nitrogen dioxide and nitrous acid on respiratory symptoms during the first year of life. METHODS: Nitrogen dioxide and nitrous acid concentrations were measured once (1996-1998) in the homes of 768 infants who were at risk for developing asthma. Infants were living in southern New England. The frequency of respiratory symptoms in these children was recorded during the first year of life. RESULTS: Infants living in homes with an NO2 concentration exceeding 17.4 ppb (highest quartile) had a higher frequency of days with wheeze (rate ratio = 2.2; 95% confidence interval = 1.4-3.4), persistent cough (1.8; 1.2-2.7), and shortness of breath (3.1; 1.8-5.6) when compared with infants in homes that had NO2 concentrations lower than 5.1 ppb (lowest quartile), controlling for nitrous acid concentration. Nitrous acid exposure was not independently associated with respiratory symptoms. CONCLUSIONS: Among infants at risk for developing asthma, the frequency of reported respiratory symptoms in the first year of life was associated with levels of NO2 not currently considered to be harmful.  相似文献   

4.
To identify acute respiratory health effects associated with air pollution due to coal combustion, a subgroup of elementary school-aged children was selected from a large cross-sectional study and followed daily for eight months. Children were selected to obtain three equal-sized groups: one without respiratory symptoms, one with symptoms of persistent wheeze, and one with cough or phlegm production but without persistent wheeze. Parents completed a daily diary of symptoms from which illness constellations of upper respiratory illness (URI) and lower respiratory illness (LRI) and the symptom of wheeze were derived. Peak expiratory flow rate (PEFR) was measured daily for nine consecutive weeks during the eight-month study period. Maximum hourly concentrations of sulfur dioxide, nitrogen dioxide, ozone, and coefficient of haze for each 24-hour period, as well as minimum hourly temperature, were correlated with daily URI, LRI, wheeze, and PEFR using multiple regression models adjusting for illness occurrence or level of PEFR on the immediately preceding day. Respiratory illness on the preceding day was the most important predictor of current illness. A drop in temperature was associated with increased URI and LRI but not with increased wheeze or with a decrease in level of PEFR. No air pollutant was strongly associated with respiratory illness or with level of PEFR, either in the group of children as a whole, or in either of the symptomatic subgroups; the pollutant concentrations observed, however, were uniformly lower than current ambient air quality standards. Moreover, since exposure estimation based on monitoring of ambient air likely results in misclassification of the true exposure, the negative findings of this study must be interpreted cautiously.  相似文献   

5.
The weekly changes in ambient sulfur dioxide, nitrogen dioxide, and temperature were compared with the figures for respiratory infection in children and adults and for absenteeism from day-care centers (DCC), schools, and workplaces during a 1-year period in Helsinki. The annual average level of sulfur dioxide was 21 micrograms/m3 and of nitrogen dioxide 47 micrograms/m3; the average temperature was +3.1 degrees C. The levels of these pollutants and the temperature were significantly correlated with the number of upper respiratory infections reported from health centers. Low temperature also correlated with increased frequency of acute tonsillitis, of lower respiratory tract infection among DCC children, and of absenteeism from day-care centers, schools and workplaces. Furthermore, a significant association was found between levels of sulfur dioxide and absenteeism. After statistical standardization for temperature, no other correlations were observed apart from that between high levels of sulfur dioxide and numbers of upper respiratory tract infections diagnosed at health centers (P = 0.04). When the concentrations of sulfur dioxide were above the mean, the frequency of the upper respiratory tract infections was 15% higher than that during the periods of low concentration. The relative importance of the effects of low-level air pollution and low temperature on health is difficult to assess.  相似文献   

6.
Air pollution and health in urban areas   总被引:10,自引:0,他引:10  
In this paper, recent reviews of the World Health Organization, other review papers, and more recent literature on the human health effects of current air pollution trends in urban areas are reviewed and summarized as follows: Sulphur dioxide. Some studies, but not others, found associations between sulphur dioxide (SO2) exposure and daily mortality and morbidity. Single-pollutant correlations sometimes disappeared when other pollutants, especially suspended particulate matter (SPM), were included. Cross-sectional studies with asthmatics revealed significant, non-threshold relations between SO2 and decrements of the forced expiratory volume in 1 second (FEV1). Nitrogen dioxide. Weak associations between short-term nitrogen dioxide (NO2) exposure from gas cooking and respiratory symptoms and a decrement in lung function parameters were found in children, but not consistently in exposed women. With long-term exposure, children, but not adults, exhibit increased respiratory symptoms, decreased lung function, and increased incidences of chronic cough, bronchitis, and conjunctivitis. A causal relationship between NO2 exposure and adverse health effects has not yet been established. Carbon monoxide. Binding of CO in the lungs with hemoglobin in the blood forms carboxyhemoglobin (COHb), which impairs the transport of oxygen. The health effects of CO include hypoxia, neurological deficits and neurobehavioral changes, and increases in daily mortality and hospital admissions for cardiovascular diseases. The latter persists even at very low CO levels, indicating no threshold for the onset of these effects. Whether the relation between daily mortality and exposure to CO are causal or whether CO might act as a proxy for SPM is still an open question. Ambient CO may have even more serious health consequences than does COHb formation and at lower levels than that mediated through elevated COHb levels. Ozone. Short-term acute effects of O3 include pulmonary function decrements, increased airway responsiveness and airway inflammation, aggravation of pre-existing respiratory diseases like asthma, increases in daily hospital admissions and emergency department visits for respiratory causes, and excess mortality. Exposure-response relations are non-linear for the respective associations between O3 and FEV1, inflammatory changes, and changes in hospital admissions, whereas the relation between percent change in symptom exacerbation among adults and asthmatics is linear. Single-pollutant associations between O3 exposure and daily mortality and hospital admissions for respiratory diseases is statistically significant, even in multi-pollutant models. Suspended particulate matter. Associations between SPM concentrations and mortality and morbidity rates are significant. The acute health effects of SPM, even at short-term low levels of exposure, include increased daily mortality and hospital admission rates for exacerbation of respiratory disease, fluctuations in the prevalence of bronchodilator use, and cough and peak flow reductions, as well as long-term effects with respect to mortality and respiratory morbidity. Such effects depend on particle size and concentration and can fluctuate with daily fluctuations in PM10 or PM2.5 levels. The relation between PM10 or PM2.5 exposure and acute health effects is linear at concentrations below 100 micrograms/m3. Currently no threshold has been reported below which no effects occur. The influence of co-polluting gaseous pollutants could explain part of the observed variance in short-term health effects and reduce the contribution of SPM. Lead. The biological effects of lead can be related to blood lead levels, the best indicator of internal exposure. The potential effects of lead in adults and children include encephalopathic signs and symptoms, central nervous system symptoms, cognitive effects, increased blood pressure, and reduced measures of child intelligence. (ABSTRACT TRUNCATED)  相似文献   

7.
BACKGROUND: Previous research on air pollution effects has found associations with chronic adverse health effects even at the relatively low levels of ambient particulates currently measured in most urban areas. METHODS: We assessed the impact of declines of total suspended particulates and sulfur dioxide in eastern Germany after reunification on the prevalence of nonallergic respiratory disorders in children. In the 1990s, particle mass (total suspended particulates) and sulfur dioxide declined, whereas number concentrations of nucleation-mode particles (10-30 nm) increased. In three study areas, questionnaires for 7,632 children between 5 and 14 years of age were collected in three phases: 1992-1993, 1995-1996, and 1998-1999. RESULTS: Adjusted odds ratios (ORs) and 95% confidence intervals (CIs) for a 50-microg/m3 increment in total suspended particulates were 3.0 (CI = 1.7-5.3) for bronchitis, 2.6 (CI = 1.0-6.6) for sinusitis, and 1.9 (CI = 1.2-3.1) for frequent colds. The effect sizes for a 100-microg/m3 increment in sulfur dioxide were similar. The effect estimates for ambient total suspended particulates and sulfur dioxide were stronger among children not exposed to gas stove emissions, visible molds or dampness, cats, or environmental tobacco smoke. CONCLUSIONS: The decreasing prevalence of nonallergic respiratory symptoms, along with improvements in ambient particle mass and sulfur dioxide (but not in nucleation-mode particles), indicates the reversibility of adverse health effects in children. This adds further evidence of a causal association between combustion-related air pollutants and childhood respiratory symptoms.  相似文献   

8.
We examined the associations between gaseous pollutants and hospitalization for chronic obstructive pulmonary diseases (COPD) among elderly people living in Vancouver, British Columbia, Canada, a city in which ambient air pollution levels are relatively low. We regressed the logarithm of daily counts of acute COPD hospitalization during the 5-year period from 1994 to 1998 on the daily mean levels of each pollutant, after accounting for seasonal and subseasonal fluctuations, non-Poisson dispersion, and weather variables. Nitrogen dioxide and carbon monoxide were significantly associated with hospitalization for COPD, and the magnitude of effects was increased slightly with increasing days of exposure averaging, with the relative risk for a 7-day average being 1.11 (95%CI: 1.04, 1.20) and 1.08 (1.02, 1.13) for nitrogen dioxide and carbon monoxide, respectively. There was no significant association between either sulfur dioxide or ozone and COPD hospitalization. The combined relative risk for all four gaseous pollutants on COPD hospitalization was 1.21. The effects of gaseous pollutants on COPD hospitalization were not significant after adjustment for PM(10), although its inclusion did not have a marked effect on the point estimates for relative risks. Nitrogen dioxide has a significant impact on COPD hospitalization. Further studies are needed to separate the effects of single pollutants from the combined effects of the complex mixture of air pollutants in urban atmospheres.  相似文献   

9.
The association of air pollution with the prevalence of chronic lower respiratory tract symptoms among children with a history of asthma or related symptoms was examined in a cross-sectional study. Parents of a total of 3,676 fourth, seventh, and tenth graders from classrooms in 12 communities in Southern California completed questionnaires that characterized the children's histories of respiratory illness and associated risk factors. The prevalences of bronchitis, chronic phlegm, and chronic cough were investigated among children with a history of asthma, wheeze without diagnosed asthma, and neither wheeze nor asthma. Average ambient annual exposure to ozone, particulate matter (PM(10) and PM(2.5); [less than/equal to] 10 microm and < 2.5 microm in aerodynamic diameter, respectively), acid vapor, and nitrogen dioxide (NO(2)) was estimated from monitoring stations in each community. Positive associations between air pollution and bronchitis and phlegm were observed only among children with asthma. As PM(10) increased across communities, there was a corresponding increase in the risk per interquartile range of bronchitis [odds ratio (OR) 1.4/19 microg/m(3); 95% confidence interval (CI), 1.1-1.8). Increased prevalence of phlegm was significantly associated with increasing exposure to all ambient pollutants except ozone. The strongest association was for NO(2), based on relative risk per interquartile range in the 12 communities (OR 2.7/24 ppb; CI, 1.4-5.3). The results suggest that children with a prior diagnosis of asthma are more likely to develop persistent lower respiratory tract symptoms when exposed to air pollution in Southern California.  相似文献   

10.
This study determined the health effects of ambient air pollutants in two grade school populations in Akron, Ohio. One school is adjacent to industry and has elevated levels of sulfur dioxide (SO2) and moderate levels of nitrogen dioxide (NO2), while the other school is 4 km east and unpolluted. This study was designed in this manner for two purposes: (1) to identify and monitor ambient levels of air pollutants in an area proximal to the grade school so that the levels could be accurately assessed, and (2) to determine baseline pulmonary function values and questionnaire responses from the parents indicating any acute and/or chronic respiratory problem in the child. Ninety-five percent of the children enrolled in this study lived within 2 km of the schools and aerometric stations, thus providing for careful control in the study design.

The results of this study indicate that SO2 and NO2 levels are significantly higher in the school adjacent to industry. Although pulmonary function data were not significantly different between schools, the frequency of questionnaire responses to acute and chronic pulmonary problems was greater in the children at the school adjacent to industry. The data tend to indicate early pulmonary effects of air pollution in children living adjacent to industry and exposed to elevated levels of SO2 and NO2. We suggest that additional longitudinal work that carefully monitors total suspended particulates, NO2, SO2, and health data should be conducted to confirm these results.  相似文献   

11.
BACKGROUND: Living near traffic has been associated with asthma and other respiratory symptoms. Most studies, however, have been conducted in areas with high background levels of ambient air pollution, making it challenging to isolate an independent effect of traffic. Additionally, most investigations have used surrogates of exposure, and few have measured traffic pollutants directly as part of the study. OBJECTIVE: We conducted a cross-sectional study of current asthma and other respiratory symptoms in children (n = 1,080) living at varying distances from high-traffic roads in the San Francisco Bay Area, California, a highly urbanized region characterized by good regional air quality due to coastal breezes. METHODS: We obtained health information and home environmental factors by parental questionnaire. We assessed exposure with several measures of residential proximity to traffic calculated using geographic information systems, including traffic within a given radius and distance to major roads. We also measured traffic-related pollutants (nitrogen oxides and nitrogen dioxide) for a subset of households to determine how well traffic metrics correlated with measured traffic pollutants. RESULTS: Using multivariate logistic regression analyses, we found associations between current asthma and residential proximity to traffic. For several traffic metrics, children whose residences were in the highest quintile of exposure had approximately twice the adjusted odds of current asthma (i.e., asthma episode in the preceeding 12 months) compared with children whose residences were within the lowest quintile. The highest risks were among those living within 75 m of a freeway/highway. Most traffic metrics correlated moderately well with actual pollutant measurements. CONCLUSION: Our findings provide evidence that even in an area with good regional air quality, proximity to traffic is associated with adverse respiratory health effects in children.  相似文献   

12.
工业区大气污染对儿童肺功能影响研究   总被引:14,自引:3,他引:11  
本文研究工业区大气污染对儿童肺功能影响,分别对大气污染区与对照区儿童进行肺功能测定、问卷调查及大气中SO2NOx监测。  相似文献   

13.
14.
We enrolled a cohort of primary school children with a history of wheeze (n=148) in an 11-month longitudinal study to examine the relationship between ambient air pollution and respiratory morbidity. We obtained daily air pollution (ozone, particulate matter less than 10 microm, and nitrogen dioxide), meteorological, and pollen data. One hundred twenty-five children remained in the final analysis. We used logistic regression models to determine associations between air pollution and respiratory symptoms, asthma medication use, and doctor visits for asthma. There were no associations between ambient ozone concentrations and respiratory symptoms, asthma medication use, and doctor visits for asthma. There was, however, an association between PM(10) concentrations and doctor visits for asthma (RR=1.11, 95% CI=1.04-1.19) and between NO(2) concentration and wet cough (RR=1.05, 95% CI=1.003-1.10) in single-pollutant models. The associations remained significant in multipollutant models. There was no consistent evidence that children with wheeze, positive histamine challenge, and doctor diagnosis of asthma reacted differently to air pollution from children with wheeze and doctor diagnosis of asthma and children with wheeze only. There were significant associations between PM(10) levels and doctor visits for asthma and an association between NO(2) levels and the prevalence of wet cough. We were, however, unable to demonstrate that current levels of ambient air pollution in western Sydney have a coherent range of adverse health effects on children with a history of wheezing.  相似文献   

15.
Adverse health consequences associated with human exposure to nitrogen dioxide are well documented. In order for policymakers to assess health risks and implement appropriate control strategies, accurate information is required concerning (1) the number of people exposed, (2) the severity and patterns of exposure, and (3) the health-related effects of exposure. In the past, data from central monitoring sites have been used to establish air pollution exposures. However, it is now recognized that people spend much of their time indoors or in areas away from fixed monitors where pollutant concentrations may be drastically different. An attempt to provide a more realistic estimate of nitrogen dioxide exposures is made. A simple deterministic model is developed, relating exposure to background ambient levels, indoor values, and human activities. Ambient and indoor parameters are derived from monitoring programs in six U.S. cities. Results suggest indoor nitrogen dioxide concentrations in private dwellings vary primarily with outdoor levels and type of cooking fuel, but are also affected by factors such as air-exchange rates and strength of indoor sources. Estimates of population exposures are obtained by combining observed distributions of nitrogen dioxide concentrations from outdoor and indoor settings with information about number of people and time spent in each microenvironment.  相似文献   

16.
Evidence that indoor dampness and mold growth are associated with respiratory health has been accumulating, but few studies have been able to examine health risks in relation to measured levels of indoor mold exposure. In particular, little is known about the contribution of indoor molds to the development of allergic sensitization. As a part of an ongoing study examining the effects of ambient air pollutants on respiratory health and atopic diseases in German school children, we examined the relation between viable mold levels indoors and allergic sensitization in 272 children. We examined whether allergic sensitization in children is associated with higher fungal spore count in settled house dust sampled from living room floors. Adjusting for age, sex, parental education, region of residency, and parental history of atopy, we found that mold spore counts for Cladosporium and Aspergillus were associated with an increased risk of allergic sensitization. Sensitized children exposed to high levels of mold spores (> 90th percentile) were more likely to suffer from symptoms of rhinoconjunctivitis. We conclude that elevated indoor concentrations of molds in wintertime might play a role in increasing the risk of developing atopic symptoms and allergic sensitization not only to molds but also to other common, inhaled allergens. These effects were strongest in the group of children who had lived in the same home since birth.  相似文献   

17.
The authors investigated the effects of ambient air pollution on hospital admissions in Brisbane, Australia. The authors used the Air Pollution on Health: European Approach protocol to examine the effects of particles, ozone, sulfur dioxide, and nitrogen dioxide on daily hospital admissions for asthma and respiratory, cardiovascular, and digestive disorders (control diagnosis) that occurred during the period 1987-1994. Ozone was consistently associated with admissions for asthma and respiratory disease-with little evidence of a threshold. In two-pollutant models, the ozone effect was relatively unaffected by the control for high levels of other pollutants. Particulate pollution (measured by nephelometry) was associated positively with admissions for respiratory disease and admissions for asthma in summer, whereas a negative association was observed for cardiovascular admissions. Although sulfur dioxide was associated significantly with admissions for respiratory and cardiovascular disese, a significant association was also found for the control diagnosis of digestive disorders. No significant associations were found for nitrogen dioxide over the study period, although significantly positive seasonal interactions were found for asthma and respiratory disease in autumn, winter, and spring. It was concluded that current levels of ambient air pollution in Brisbane make a significant contribution to the variation in daily hospital admissions for asthma and respiratory disease.  相似文献   

18.
The relation between respiratory illness and atmospheric smoke and sulphur dioxide (SO2) was investigated from 1973 to 1977 in children aged 6 to 11 from a random sample of 28 areas in England and Scotland. Cross-sectional results are presented for 1975, and results from other years briefly summarised. In 1975 there were 19 areas with data on pollution and in these areas the sample included 5787 children of white ethnic origin of whom 4116 (71%) had complete information of respiratory illness and other variables considered in the analysis. After allowing for the effects of age, social class, population density, type of fuel used for cooking in the home, and season of examination, the prevalence of respiratory illness in both sexes was in the home, and season of examination, the prevalence of respiratory illness in both sexes was positively associated with the levels of smoke over the range of annual means 8 to 51 microgram/m3 )P less than or equal to 0.05). No relation was found between illness and annual means of SO2 ranging from 12 to 114 microgram/m3. Similar results were found in other years, and in 1977, when information of tobacco smoking at home was collected, the association between illness and atmospheric smoke appeared to be independent of smoking within the home. The levels of smoke were much lower than those at which effects on health hve previously been reported so the association is unlikely to be causative. We postulate that higher levels of atmospheric pollution at an earlier period in some areas may have predisposed children living there to respiratory illness during their primary school years. Alternatively, some other characteristics of the polluted areas may explain the findings.  相似文献   

19.
The authors investigated the effects of ambient air pollution on hospital admissions in Brisbane, Australia. The authors used the Air Pollution on Health: European Approach protocol to examine the effects of particles, ozone, sulfur dioxide, and nitrogen dioxide on daily hospital admissions for asthma and respiratory, cardiovascular, and digestive disorders (control diagnosis) that occurred during the period 1987-1994. Ozone was consistently associated with admissions for asthma and respiratory disease—with little evidence of a threshold. In two-pollutant models, the ozone effect was relatively unaffected by the control for high levels of other pollutants. Particulate pollution (measured by nephelometry) was associated positively with admissions for respiratory disease and admissions for asthma in summer, whereas a negative association was observed for cardiovascular admissions. Although sulfur dioxide was associated significantly with admissions for respiratory and cardiovascular disease, a significant association was also found for the control diagnosis of digestive disorders. No significant associations were found for nitrogen dioxide over the study period, although significantly positive seasonal interactions were found for asthma and respiratory disease in autumn, winter, and spring. It was concluded that current levels of ambient air pollution in Brisbane make a significant contribution to the variation in daily hospital admissions for asthma and respiratory disease.  相似文献   

20.
Effect of nitrogen dioxide on antibacterial activity in vivo was investigated by simultaneously determining physical removal and bactericidal activity rates of murine lung. Mice were exposed to various concentrations of nitrogen dioxide for 17 hours prior to or 4 hours after infection with aerosols of Staphylococcus aureus labeled with radioactive phosphorus (32P). Animals infected and then exposed to levels of nitrogen dioxide above 7.0 ppm showed a progressive decrease in percent pulmonary bactericidal activity which could not be accounted for by physical removal of bacteria. Exposure to levels of nitrogen dioxide of 2.3 ppm or greater for 17 hours prior to staphylococcal infection caused decreases in bactericidal activity. The finding that murine resistance to infection is diminished at exposure levels only slightly above ambient (2.3 ppm) suggests that human populations may incur a similar risk.  相似文献   

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