Confounding or aggravating factors in noise-induced health effects: air pollutants and other stressors.

Different scientific groups have studied and continue to study the health impacts of physical and chemical agents in the environment. In most cases, every study group has considered the health effect as being solely due to the air pollutant(s) under investigation, for example air pollution without due regard for the simultaneous presence of noise pollution whereas both have an impact on the cardiovascular system. Or in the case of noise studies the contribution of solvent, asphyxiant or metal exposures has not been considered, which can have an impact on hearing impairment. One can, therefore, question the stringency of the available evidence of epidemiological studies in both fields to warrant the consideration of air pollutants as confounding or aggravating factors in studies of specific effects due to noise (and vice versa). In this paper we weigh the existing evidence on the association of noise and air pollutant exposure and associated health impacts. In forthcoming publications, the authors will consider the influence of other factors, which can confound noise studies but are currently not included in the analysis.

Exposure to environmental chemicals relevant for respiratory hypersensitivity: global aspects.

Trends of air pollutant concentrations that influence the incidence of respiratory diseases and might be influential for respiratory hypersensitivity are presented and discussed. Data for these trends are collected in UNEP/WHO's Global Environmental Monitoring System GEMS/Air which recently has been revitalized and redirected to become a tool for providing the information necessary for rational air quality management. Data are interpreted with respect to WHO's most recent air quality guidelines, which are an update of the air quality guidelines for Europe published in 1987. A WHO study on the global disease burden and the contribution of air pollution to it is discussed and global estimates of mortality resulting from air pollution through sulphur dioxide and suspended particulate matter, by different economic regions, are given. Starting from the air quality guidelines still valid at the time of publication of the update, about 460,000 excess deaths globally are due to suspended particulate matter and about 370,000 to sulphur dioxide.

Air pollution and health in urban areas.

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)

Chernoff-Flury faces: a statistical means for representing multivariate response parameters of air pollution induced injury on plants.

To evaluate the effects of dry and wet deposition on forest trees (Picea abies [L.] Karst.), the LIS-Essen is operating an Open-Top Chamber Field Station within an area where novel forest decline has been prevalent since 1982. Chambers are ventilated with either ambient or charcoal-filtered air and receive either natural or artificial rain, the latter being prepared by natural rain and distilled water in ratio 1:10. Besides deposition data, acquired above and below the tree crowns as well as via lysimeters of soil percolates, various parameters describing vitality of trees are measured. To obtain a persuading representation of total parameters and their interdependencies, a multivariate graphical cluster analysis has been performed by use of Chernoff-Flury faces. Interdependencies of vitality parameters are more easily recognizable in this multivariate picture than in usually applied binary correlation diagrams.

Cooking smoke: a silent killer.

PIP: This article discusses the impact of cooking stoves in developing countries on indoor air quality and human health. About 50% of the world's households rely on wood, stubble, dung, and grass for cooking fuel. These products are burned in open fires and inefficient stoves in poorly ventilated rooms. Biomass smoke contains many harmful pollutants, such as particles and carbon monoxide. Coal smoke contains sulphur and nitrogen oxides and hydrocarbons that can cause cancer. Biomass smoke can cause acute respiratory infections. Women and children receive the highest exposure to biomass smoke. About 2500 million people are exposed to excessive levels of indoor air pollution, of which most is due to burning biomass and coal indoors with poor ventilation. About 1.9 million deaths annually are attributed to rural indoor air pollution from suspended particulate matter. About 450,000 deaths annually are attributed to urban indoor air pollution. An additional 500,000 deaths are attributed to other suspended particulate matter and sulphur dioxide in the atmosphere. Particulate suspensions in the air are especially problematic in rural African countries and rural India. Particulates are acutely problematic in urban Latin America, India, and China. One study in The Gambia found that girls younger than 5 who were around mothers who were cooking had a 6-times higher risk of acute respiratory infections (ARI) than those around parents who smoked cigarettes. It is the products of incomplete combustion that pose the greatest risk to health. A 1993 study in Kenya found that the use of the jiko stove lowered ARI and conjunctivitis. The Indoor Air 99 Conference in Edinburgh is planned for August 1999 and will emphasize the health hazards of indoor air pollution. Behavioral change is not easy. The first step is persuading people that biomass smoke exposure is harmful and a serious health hazard.^ieng

Public health and the Air Management Information System (AMIS).

This paper discusses the importance of public health studies with respect to risk assessment and risk management in the framework of air quality management. This is performed with respect to the Air Management Information System (AMIS), which was set up recently by the World Health Organization. The Air Management Information System is an information-exchange system in the scheme of the Global Air Quality Partnership providing information on all issues of air quality management between its participants: municipalities, countries' environmental protection agencies, international organizations, World Bank and international development banks, and nongovernmental organizations. Public health studies of air pollution-induced health effects are an important ingredient for decisions with respect to the management of air quality. First, they are to be used to derive air quality standards from air quality guidelines. Secondly, they serve to assess the causal link between observed health effects in the population and the causative agents in the air. Thirdly, they can be used to estimate ideal (in the sense of not being expressed in monetary terms) or economic damage functions that are necessary to assess the magnitude of the ideal or economic damages to human health. The latter are necessary for a sensible cost-benefit analysis in which the costs of control measures to reduce air pollution are compared with the costs of health effects.