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PubMed1992

Atmospheric pollution.

Air pollution has been directly responsible for increases in mortality and morbidity in the general population during periods known as episodes, when pollutant levels were elevated well above those that occur on a regular basis. The major concern today regarding pollution and health is, however, more subtle--namely, whether the lower levels of pollution to which we are exposed daily are harmful to health. It is extremely difficult to relate specific health problems to specific pollutants, because other environmental and lifestyle factors may contribute to decrements in health. Furthermore, people are generally exposed to mixtures of pollutants, making it difficult to extract the effects caused by individual components, or to determine which combinations are the most hazardous. Community air pollution results from various sources: mobile sources, such as vehicles; stationary sources, such as power plants and factories; and indoor sources, such as building material. Complicating the picture is the fact that many chemicals released into the air may react, producing additional secondary pollutants. This article provides an overview of the major air pollutants that may be of concern in terms of public health.

Air Pollutants↗

PubMed2003

Strategies for emission reduction of air pollutants produced from a chemical plant.

Various air pollution control (APC) techniques were employed in order to reduce emissions of air pollutants produced from chemical plants, which have many different chemical production facilities. For an emission reduction of acid gases, this study employed a method to improve solubility of pollutants by decreasing the operating temperature of the scrubbers, increasing the surface area for effective contact of gas and liquid, and modifying processes in the acid scrubbers. To reduce emission of both amines and acid gases, pollutant gas components were first separated, then condensation and/or acid scrubbing, depending on the chemical and physical properties of pollutant components, were used. To reduce emission of solvents, condensation and activated carbon adsorption were employed. To reduce emission of a mixture gases containing acid gases and solvents, the mixed gases were passed into the first condenser, the acid scrubber, the second condenser, and the activated carbon adsorption tower in sequence. As a strategy to reduce emission of pollutants at the source, this study also employed the simple pollution prevention concept of modification of the previously operating APC control device. Finally, air emissions of pollutants produced from the chemical plants were much more reduced by applying proper APC methods, depending upon the types (physical or chemical properties) and the specific emission situations of pollutants.

Adsorption↗

PubMed2005

A spatial temporal assessment of pollution from PCBs in China.

This research represents an assessment of the current state of pollution from polychlorinated biphenyls (PCBs) in China. Various environmental media including sediment, water, organism and soil were analyzed and the spatial character of PCB pollution in each environmental medium was determined. On a national basis, PCB levels in all environmental media were relatively low, with little evidence of major contamination in China's main regions and rivers. However, there were some locations with high PCB concentrations. Sediments in Pearl River (83.1 ng/g) and its estuary (58.9 ng/g), Dalian Bay (58.1 ng/g) and Songhua River (36.8 ng/g) had relatively high level of PCBs. There were also some areas, which were mainly the industrial pollution sites or PCB equipment storage locations, remained seriously polluted with the highest PCB residue level of 150,000 ng/g. In addition, Minjiang Estuary (985.2 ng/g) and Taihu Lake (631 ng/g) had high levels of water pollution, while Pearl Estuary (635.7 ng/g) and Jiaozhou Bay (273.3 ng/g) had relatively high PCB levels in organisms. PCB pollution in soil was limited to a few special pollution areas with the highest PCB level of 4.5448 x 10(6) ng/g. Point source pollution was the common pattern of contamination, influenced primarily by local geographic, economic and historical factors. Analysis of PCB concentrations from the 1980s to 1990s shows an increasing trend, possibly due to the improper disposal of and leakage from PCB containers, chemical transfers, and the general rise of industrial pollution.

Animals↗

PubMed2005

Seasonal variation of air pollution index: Hong Kong case study.

Air pollution is an important and popular topic in Hong Kong as concerns have been raised about the health impacts caused by vehicle exhausts in recent years. In Hong Kong, sulphur dioxide SO2, nitrogen dioxide (NO2), nitric oxide (NO), carbon monoxide (CO), and respirable suspended particulates (RSP) are major air pollutants caused by the dominant usage of diesel fuel by goods vehicles and buses. These major pollutants and the related secondary pollutant, e.g., ozone (O3), become and impose harmful impact on human health in Hong Kong area after the northern shifting of major industries to Mainland China. The air pollution index (API), a referential parameter describing air pollution levels, provides information to enhance the public awareness of air pollutions in time series since 1995. In this study, the varying trends of API and the levels of related air pollutants are analyzed based on the database monitored at a selected roadside air quality monitoring station, i.e., Causeway Bay, during 1999-2003. Firstly, the original measured pollutant data and the resultant APIs are analyzed statistically in different time series including daily, monthly, seasonal patterns. It is found that the daily mean APIs in seasonal period can be regarded as stationary time series. Secondly, the auto-regressive moving average (ARMA) method, implemented by Box-Jenkins model, is used to forecast the API time series in different seasonal specifications. The performance evaluations of the adopted models are also carried out and discussed according to Bayesian information criteria (BIC) and root mean square error (RMSE). The results indicate that the ARMA model can provide reliable, satisfactory predictions for the problem interested and is expecting to be an alternative tool for practical assessment and justification.

Air Pollutants↗

PubMed2005

Influence of set-up conditions of exposure indicators on the estimate of short-term associations between urban pollution and mortality.

In the past few years many studies on air pollution and health based on time series have been carried out. Yet, this approach does not assess exposure to air pollution at an individual level but it is based on ambient concentrations measured by air quality monitoring networks. Questions on the estimates of exposure to pollutants have been raised, in particular the fact that background measuring stations only have been considered in the set up of pollution indicators. To assess the impact of exposure indicator characteristics on the results of time series analysis, two series (black smoke and sulfur dioxide, respectively) of exposure indicators to urban air pollution were set up taking into account a growing part of proximity measures (industrial sources) available in the studied urban area (Le Havre, France). For each pollutant, indicators distributions were almost similar, especially for black smoke. Whatever the pollutant, the most obvious heterogeneity could be observed between the 100% background indicator and the indicator including the arithmetic mean for all the stations (50% background stations and 50% proximity stations). Then the sensitivity of the associations between mortality and air pollution to these indicators was studied. These indicators did not show statistically significant differences in the estimated excess risk. Yet, confidence intervals were more statistically significant as the contribution of proximity stations was more substantial, in particular for SO2. To conclude, the use of proximity measurements did not influence dramatically on the mean estimates of the association between air pollution and mortality indicators in Le Havre. Therefore it does not seem relevant to include the data provided by the proximity stations in the urban exposure indicators within the context of the epidemiology monitoring system.

Air Pollutants↗

PubMed2003

Review of air pollution and health impacts in Malaysia.

In the early days of abundant resources and minimal development pressures, little attention was paid to growing environmental concerns in Malaysia. The haze episodes in Southeast Asia in 1983, 1984, 1991, 1994, and 1997 imposed threats to the environmental management of Malaysia and increased awareness of the environment. As a consequence, the government established Malaysian Air Quality Guidelines, the Air Pollution Index, and the Haze Action Plan to improve air quality. Air quality monitoring is part of the initial strategy in the pollution prevention program in Malaysia. Review of air pollution in Malaysia is based on the reports of the air quality monitoring in several large cities in Malaysia, which cover air pollutants such as Carbon monoxide (CO), Sulphur Dioxide (SO2), Nitrogen Dioxide (NO2), Ozone (O3), and Suspended Particulate Matter (SPM). The results of the monitoring indicate that Suspended Particulate Matter (SPM) and Nitrogen Dioxide (NO2) are the predominant pollutants. Other pollutants such as CO, O(x), SO2, and Pb are also observed in several big cities in Malaysia. The air pollution comes mainly from land transportation, industrial emissions, and open burning sources. Among them, land transportation contributes the most to air pollution. This paper reviews the results of the ambient air quality monitoring and studies related to air pollution and health impacts.

Air Pollutants↗

PubMed1997

Increased plasma viscosity during an air pollution episode: a link to mortality?

BACKGROUND: Air pollution episodes have been consistently associated with increased mortality, and most strikingly with mortality due to cardiovascular disease. One hypothesis to explain this association is that inflammation of the peripheral airways caused by pollution might increase blood coagulability. We have tested this hypothesis in a cross-sectional study by comparing measurements of plasma viscosity during a severe episode of air pollution during 1985 with those made on less polluted days. METHODS: Plasma viscosity was measured as part of the MONICA Augsburg survey during the winter of 1984-85 in 3256 randomly selected men and women aged 25-64 years. Daily mean concentrations of air pollutants and meteorological variables were measured in Augsburg as part of the automated Bavarian air-quality network. We compared measurements of plasma viscosity made in 324 people who attended for screening during the pollution episode and in 2932 people screened during the remainder of the survey period. FINDINGS: In January, 1985, high concentrations of sulphur dioxide (mean 200 micrograms/m3) and total suspended particles (mean 98 micrograms/m3) were recorded during a 13-day period in Augsburg. In men, the odds ratio for plasma viscosity above the 95th percentile of the distribution (1.38 mPa s) was 3.6 (95% CI 1.6-8.1) comparing measurements during the air pollution episode with non-episode measurements after adjustment for cardiovascular risk factors and meteorological variables. The corresponding odds ratio for women (95th percentile of plasma viscosity 1.37 mPa s) was 2.3 (1.0-5.3). High concentrations of carbon monoxide were also associated with increased plasma viscosity in women. INTERPRETATION: During the 1985 air pollution episode, an increased risk of extreme values of plasma viscosity was observed in both men and women. Altered blood rheology due to inflammatory processes in the lung that induce an acute-phase reaction might therefore be part of the pathological mechanisms linking air pollution to mortality.

Adult↗

PubMed2006

[Air pollution and cardiovascular and cerebrovascular disease: Epidemiologic data].

Recent convergent data suggest that air pollution affects the risk of acute atherothrombotic events including both myocardial infarction and ischemic stroke. The principal epidemiologic studies begun in the 1990s first examined the respiratory effects of atmospheric pollution and then focused on how pollution peaks affected cardiovascular risk. These studies used data from large metropolitan areas in North America and Asia as well as several large European cities to demonstrate the clear existence of a relation between air pollution and cardio- and cerebrovascular mortality. They also observed an increase in hospital admissions for myocardial infarctions and cerebrovascular accidents on days with high air pollution levels. The pollutants involved have not yet been clearly designated, but it appears that fine suspended particulate matter (PM2.5) and gaseous pollutants such as ozone appear to contribute strongly to these harmful effects. A complete analysis of these data shows the need for a thorough evaluation of the cardio- and cerebrovascular risks associated with air pollution, especially in French metropolitan areas. Precise identification of those at high risk from specific pollutants is essential to improve targeting of prevention strategies.

Air Pollutants↗

PubMed2005

Patterns of household concentrations of multiple indoor air pollutants in China.

Most previous studies on indoor air pollution from household use of solid fuels have used either indirect proxies for human exposure or measurements of individual pollutants at a single point, as indicators of (exposure to) the mixture of pollutants in solid fuel smoke. A heterogeneous relationship among pollutant-location pairs should be expected because specific fuel-stove technology and combustion and dispersion conditions such as temperature, moisture, and air flow are likely to affect the emissions and dispersion of the various pollutants differently. We report on a study for monitoring multiple pollutants--including respirable particles (RPM), carbon monoxide, sulfur dioxide, fluoride, and arsenic--at four points inside homes that used coal and/or biomass fuels in Guizhou and Shaanxi provinces of China. All pollutants exhibited large variability in emissions and spatial dispersion within and between provinces and were generally poorly correlated. RPM, followed by SO2, was generally higher than common health-based guidelines/standards and provided sufficient resolution for assessing variations within and between households in both provinces. Indoor heating played an important role in the level and spatial patterns of pollution inside homes, possibly to an extent more important than cooking. The findings indicate the need for monitoring of RPM and selected other pollutants in longer-term health studies, with focus on both cooking and living/sleeping areas.

Air Pollutants↗

PubMed2005

Air pollution in Australia: review of costs, sources and potential solutions.

ISSUE ADDRESSED: Estimated health costs and principal sources of air pollution are reviewed, together with estimated costs of reducing pollution from major sources in Australia. METHOD: Emissions data from the Australian National Pollutant Inventory were compared with published estimates of pollution costs and converted to the cost per kilogram of emissions. Costs per kg of emissions (and, for the two main sources of pollution, diesel vehicles and wood heaters, costs per heater and per vehicle) are relatively easy to understand, making it easier to compare health costs with costs of pollution-control strategies. RESULTS: Estimated annual costs of morbidity/mortality exceed $1,100 per diesel vehicle and $2,000 per wood heater. Costs of avoiding emissions (about $2.1/kg PM2.5 for phasing out wood heaters and upwards of $70/kg for reducing diesel emissions) are considerably less than the estimated health costs ($166/kg) of those emissions. CONCLUSIONS: In other countries, smokeless zones (for domestic heating), heavy vehicle low-emission zones, and lower registration charges for low-emission vehicles reduce pollution and improve health. Similar 'polluter-pays' taxes in Australia to encourage retrofitting of existing diesels and incentives to choose new ones with lowest emissions would provide substantial benefits. Adopting Christchurch's policy of phasing out wood heaters and 'polluter-pays' levies to discourage their use would be extremely cost-effective.

Air Pollutants↗

PubMed2004

Air pollution and cardiac arrhythmias in patients with implantable cardioverter defibrillators.

Epidemiological studies have demonstrated associations between short-term increases in outdoor air pollution concentrations and adverse cardiovascular effects, including cardiac mortality and hospitalizations. One possible mechanism behind this association is that air pollution exposure increases the risk of developing a cardiac arrhythmia. To investigate this hypothesis, dates of implantable cardioverter defibrillator (ICD) discharges were abstracted from patient records in patients attending the two ICD clinics in Vancouver, BC, for the years 1997-2000. Daily outdoor air pollutant concentrations and daily meteorological data from the Vancouver region were obtained for the same 4-yr period. Generalized estimating equations were used to assess the association between short-term increases in air pollutant concentrations and ICD discharges while controlling for temporal trends, meteorology, and serial correlation in the data. Air pollution concentrations in the Vancouver region were relatively low from 1997 to 2000, as expected. In the 50 patients who resided within the Vancouver region and who experienced at least 1 ICD discharge during the period of follow-up, no significant associations between increased air pollution concentrations and increased ICD discharges were present. When the patient sample was restricted to the 16 patients who had at least 6 months of follow-up and experienced a rate of at least 2 days with ICD discharges per year, there was a statistically significant association between increased sulfur dioxide (SO(2)) concentration and ICD discharge 2 days after the SO(2) increase. When stratified by season, no associations between increased air pollutant concentrations and increased risk of ICD discharge were observed in the summer, although for several pollutants, concentration increases were associated with a decrease in ICD discharges. In the winter, increased SO(2) concentrations again were seen to be associated with increased risk of ICD discharge, at both 2 and 3 days following increases in SO(2) concentrations. These findings provide no compelling evidence that short-term increases in relatively low concentrations of outdoor air pollutants have an adverse effect on individuals at risk of cardiac arrhythmias. The findings regarding SO(2) are difficult to interpret. They may be chance findings. Alternatively, given the very low concentrations of SO(2) that were present in Vancouver, SO(2) may have been serving as a surrogate measure of other environmental or meteorological factors.

Adolescent↗

PubMed2006

Outdoor air pollution and female lung cancer in Taiwan.

To investigate the relationship between air pollution and female lung cancer, the authors conducted a matched case-control study using female deaths that occurred in Taiwan from 1994 through 2003. Data on all eligible female lung cancer deaths were obtained from the Bureau of Vital Statistics of the Taiwan Provincial Department of Health. The control group consisted of women who died from causes other than cancer or diseases associated with respiratory problems. The controls were pair matched to the cases by sex, year of birth, and year of death. Each matched control was selected randomly from the set of possible controls for each case. A municipality-based aggregate index of long-term exposure to air pollution was created by dividing the annual average of the measured values for each pollutant by the National Ambient Air Quality Standard for that pollutant. The ratios for each pollutant were scaled to a 100-point scale and then averaged together to generate an index value representing the net burden of these pollutants, with each weighted equally. The subjects were divided into tertiles according to the levels of the index just described. Women who lived in the group of municipalities with highest levels of air pollution exposure index were at a statistically significant increased lung cancer risk compared to the group living in municipalities with the lowest air pollution exposure index after controlling for possible confounders (OR = 1.28, 95% CI = 1.02-1.61). The findings of this study warrant further investigation of the role of air pollutants in the etiology of lung cancer.

Aged↗

PubMed1996

Air pollution and mortality in East Berlin during the winters of 1981-1989.

BACKGROUND: The relationship between air pollution and mortality in East Berlin was examined for the winters of 1981-1989. METHODS: Regression analysis included daily mean levels of sulphur dioxide (SO2) and suspended particulates (SP), and was controlled for temperature, humidity, week-day, month, and year. Moving averages of previous pollution were also used. RESULTS: Each pollutant was a significant contributor to excess mortality. The strongest association was found for mortality lagged for 2 days, which depended significantly on the level of SP (beta for in SP = 0.876; P = 0.008) and SO2 (beta for in SO2 = 0.635; P = 0.012), when regressed separately. When omitting days with pollutant concentrations above 150 micrograms m-3, the pollutant-mortality relationship was linear, and a 100 micrograms m-3 increase was associated with a 6.1% (SP) and 4.5% (SO2) mortality increase 2 days later, when pollutants were considered separately; this was reduced to 4.6% (SP) and 2.8% (SO2) increase, when both were considered simultaneously. CONCLUSIONS: The results show that short-term associations between air pollutants and mortality in East Berlin did exist during the winters 1981-1989. Since the coefficients for SP and SO2 dropped when controlling for the other pollutant species, a similar strength of association with mortality for both pollutants was found.

Air Pollutants↗

PubMed1998

Inappropriate use of daily mortality analyses to estimate longer-term mortality effects of air pollution.

BACKGROUND: To avoid the usual problems of multi-population correlation studies of air pollution and mortality, and for reasons of convenience, daily time-series mortality studies within single populations have recently become popular in air pollution epidemiology. Such studies describe how the short-term distribution of deaths relates to short-term fluctuations in air pollution levels. The regression-based risk coefficients from these acute-effects studies have been widely used to estimate the excess annual mortality within a population with a specified average level of air pollution. Such calculations are inappropriate. Since daily time-series data provide no simple direct information about the degree of life-shortening associated with the excess daily deaths (many of which are thought to be due to exacerbation of well-advanced disease, especially cardiovascular disease), such data cannot contribute to the estimation of the effects of air pollution upon chronic disease incidence and long-term death rates. Yet it is that category of effect that is of most public health importance. CONCLUSION: Such effects are best estimated from long-term cohort studies that incorporate good knowledge of local (or personal) exposure to air pollutants and of potential confounders. Time-series studies, properly evaluated, can identify the existence of acute toxic effects of transient peak levels of air pollution; they are thus useful for monitoring acute toxicity and for identifying the most noxious pollutants. However, to quantify the long-term health impacts of air pollution we cannot use acute-effects data.

Air Pollution↗

PubMed1999

Effects of ambient air pollution and environmental tobacco smoke on respiratory health of non-smoking women in Hong Kong.

BACKGROUND: Two-thirds of complaints received by the Hong Kong Environmental Protection Department in 1988 were related to poor air quality. In July 1990 legislation was implemented to reduce fuel sulphur levels. The intervention led to a reduction in respiratory symptoms and bronchial hyperresponsiveness of primary school children. The objectives of this study were to investigate the differences in respiratory health between non-smoking women living in the more polluted district (Kwai Tsing) and those living in the less polluted district (Southern); to assess the impact of the government air quality intervention; and to study the effect of environmental tobacco smoke on respiratory health in non-smoking women in both districts. METHOD: A total of 3405 non-smoking women, aged 36.5 years (standard deviation = 3.0), from two districts with good and poor air quality respectively before the intervention were followed yearly from 1989 to 1991. Binary latent variable modelling was used to summarize the six respiratory symptoms and to estimate the effects of risk factors. RESULTS: In 1989, living in the polluted district was associated with poor respiratory health (odds ratio [OR] = 1.55, 95% confidence interval [CI]: 1.11-2.17, P < 0.01). After the intervention, in the polluted district only, sulphur dioxide levels fell by up to 80% and sulphate concentrations in respirable particulates by 38%. Between 1989 and 1990-1991, there was no significantly greater decline (P > 0.241) in the more polluted compared with the less polluted district for poor respiratory health. In 1989, the effects on poor respiratory health for exposure to two or more categories of smokers relative to none in the home (OR = 1.80, 95% CI: 1.15-2.83, P < 0.01) were higher but not significantly than those for living in polluted relative to less polluted district (95% CI of the two effects overlapping each other). CONCLUSIONS: Environmental tobacco smoke (ETS) and outdoor air pollution had independent adverse effects on respiratory health of non-smoking women and improvement in air quality had produced some but non-significant benefits.

Adolescent↗

PubMedDate not supplied

Evaluating the health significance of hazardous air pollutants using monitoring data.

OBJECTIVE: Though many contaminants are released into the atmosphere, in the US only six air pollutants-ozone, particulate matter, sulfur dioxide, carbon monoxide, nitrogen dioxide, and lead-are closely monitored and carefully assessed for health significance. Other pollutants, even if highly toxic, are neither widely monitored nor routinely assessed at the national level. The goal of this study was to analyze the availability of information needed to characterize the health significance of hazardous air pollutants, focusing on urban areas in California. METHODS: The authors compared different approaches to identifying which contaminants should be considered hazardous air pollutants of potential health concern; reviewed the availability of toxicity values for these pollutants; and analyzed the usefulness of air monitoring data from California agencies for determining populations risks, by comparing method detection limits with health benchmarks. RESULTS: Approaches to identifying air contaminants of possible health concern differ. Toxicity values are not available for many hazardous air pollutants, including those identified in the Clean Air Act. In California, monitoring data are available for many, though not all, pollutants of concern. Monitoring methods for several pollutants do not have adequate sensitivity to detect all relevant concentrations. CONCLUSION: The information necessary to fully assess the health significance of hazardous air pollutants is not currently available.

Air Pollutants↗

PubMed1996

A critical review of the evidence on particulate air pollution and mortality.

We review epidemiologic studies of particulate air pollution and mortality in U.S. cities with respect to important methodologic issues. Many of these studies suffer from serious deficiencies in their control of the confounding effects of other pollutants. As a consequence, the small risks reported to be associated with the particulate component of air pollution could easily be attributed to residual confounding by co-pollutants. Most studies, moreover, have not considered modification of air pollution effects by seasonal factors, making the interpretation of the estimated risks difficult. We use a new analysis of mortality in Philadelphia that considers four pollutants simultaneously as well as seasonal effects to illustrate the methodologic issues raised in this paper. Air pollution, which is a complex mixture, appears to be associated with mortality even at the generally low levels of pollution in U.S. cities, but currently neither the statistical tools nor the biological understanding of mechanisms exists to tease out the contribution made by each component of this mixture. We conclude that it is not possible with the present evidence to show a convincing correlation between particulate air pollution and mortality.

Air Pollutants↗

PubMed1996

Health effects of outdoor air pollution. Committee of the Environmental and Occupational Health Assembly of the American Thoracic Society.

Particles, SOx, and acid aerosols are a complex group of distinct pollutants that have common sources and usually covary in concentration. During the past two decades, the chemical characteristics and the geographic distribution of sulfur oxide and particulate pollution have been altered by control strategies, specifically taller stacks for power plants, put in place in response to air pollution regulations adopted in the early 1970s. While the increasing stack heights have lowered local ambient levels, the residence time of SOx and particles in the air have been increased, thereby promoting transformation to various particulate sulfate compounds, including acidic sulfates. These sulfate particles constitute a large fraction of the total mass of smaller particles (< 3 microns in aerodynamic diameter). Epidemiologic studies have consistently provided evidence of adverse health effects of these air pollutants. Particulate and SO2 pollution were strongly implicated in the acute morbidity and mortality associated with the severe pollution episodes in Donora (Pennsylvania), London, and New York in the 1940s, 1950s, and 1960s. There is new evidence that even current ambient levels of PM10 (30 to 150 micrograms/m3) are associated with increases in daily cardiorespiratory mortality and in total mortality, excluding accidental and suicide deaths. These associations have been shown in many different communities, as widely different in particle composition and climate as Philadelphia, St. Louis, Utah Valley, and Santa Clara County, California. It has recently been shown in a long-term prospective study of adults in the United States that chronic levels of higher PM10 pollution are associated with increased mortality after adjusting for several individual risk factors. Daily fluctuations in PM10 levels have also been shown to be related to acute respiratory hospital admissions in children, to school and kindergarten absences, to decrements in peak flow rates in normal children, and to increased medication use in children and adults with asthma. Although some epidemiologic studies suggest that acid aerosols are an important toxic component of PM10, other studies do not support this hypothesis. Dockery and Pope (408) recently reviewed the epidemiologic literature for adverse effects, assuming that reported associations can be attributed to acute particle mass exposures. Combined effects were estimated as percent increase in comparable measures of mortality and morbidity, associated with each 10 micrograms/m3 increase in daily mean PM10 exposure (Table 7). While total mortality increased by 1% for each 10 micrograms/m3 increase in PM10, respiratory mortality increased by 3.4% and cardiovascular mortality increased by 1.4%. Hospital admissions and emergency department visits increased approximately 1% for all respiratory complaints, and 2% to 3% for asthma. Exacerbation of asthma increased by about 3%, as did lower respiratory symptoms. Small decreases in lung function, approximately 0.1%, have also been observed. This review suggests that the epidemiologic studies of adverse morbidity measures are coherent with the mortality studies showing quantitatively similar adverse effects of acute exposures to particulate pollution. Despite these epidemiologic findings for acute and chronic adverse health effects from air pollution associated with relatively low levels of inhalable particles, there are no complementary data from toxicologic studies or from acute human exposures to similar levels of respirable particles. Thus, controlled human exposures to various particles, including H2SO4, at relevant levels (< 150 micrograms/m3) have not identified significant alterations in respiratory function in healthy individuals.(ABSTRACT TRUNCATED)

Adult↗