Employing dynamical and chemical processes for contaminant mixtures outdoors to the indoor environment: the implications for total human exposure analysis and prevention

There are many physical and chemical processes that affect the accumulation of outdoor pollutants. In recent years some of the information and concepts previously ascribed to outdoor pollution has been found to be useful in examining indoor dynamic and chemical processes. Further, becau se of the confining nature of the indoor environment, processes such as the "grasshopper effect" can lead to sustained higher levels of semivolatile chemicals indoors and affect multiroute (inhalation, dermal, incidental dietary, and nondietary ingestion) exposures. Such processes can also lead to a complex mixture of both semivolatile and volatile compounds in indoor air and on surfaces or within objects. This article specifically examines the above in combination with another indoor issue, indoor chemistry, and places the results into a context that can be used to evaluate (1) multipollutant cumulative or aggregate exposures and risks indoors, (2) exposure reduction strategies that can create healthy indoor environments. It is not a review of the entire field of the indoor environment or indoor air or the indoor environment, which has been covered in numerous volumes and reports. The complexities of the scientific issues are discussed by also placing them into our traditional approaches outdoor and indoor to pollution management, to indicate the difficulty in establishing the exposures that require mitigation or prevention. Further, some emerging issues are discussed as well as how to specifically address long-term single or multiroute exposures to semivolatile compounds within the "Total Indoor Environment."     

Air pollution studies

The aim of this paper is to give an overview of the research in the area of air pollution, carried out exclusively at the Institute for Medical Research and Occupational Health and performed by the scientists of the Institute. For the past fifty years, air quality has been studied at work, in the ambient air of urban and industrial areas, and in various indoor environments without occupational exposure. Methods for sampling and measuring air pollutants have been introduced or developed and verified. The behaviour and the fate of air pollutants in the environment have also been investigated. Since the primary goal of the studies was to assess the extent of human exposure to air pollutants, the data were used to calculate the risk for various population groups. A dynamic model of exposure for various population groups relied on calculations of collected data, taking into account time spent in various microenvironments. This text describes the cooperation of the Institute with other institutions and agencies on the national and international level and outlines the current and prospective activities.     

Air pollution in internal environments and sick building syndrome

Indoor Air Quality (IAQ) emerged as a science from the 1970s onwards with the energy crisis and the subsequent construction of sealed buildings (without natural ventilation). This mainly occurred in developed countries and it soon came to public attention that lower levels of air exchange in these environments was the main culprit for the increase in concentration of indoor air pollutants. It is common knowledge that ventilation is one of the principal factors that interfere with air quality in indoor environments and that the occupants contribute to the pollution of these environments with their activities. Furthermore, poor indoor air quality is associated with some diseases (cough, rhinitis, allergy, etc.) and with Sick Building Syndrome (SBS). For sampling of the indoor contaminants there are several methodologies, available including passive monitoring systems, active and automatic systems. To ensure a healthy indoor environment, the application of specific legislation needs to be reconciled with research and fostering awareness among the occupants of such buildings. This survey seeks to identify the different contaminants found in internal environments, their effects on human health and the methodologies available for sampling them.     

Understanding urban exposure environments: new research directions for informing implementation of U.S. air quality standards

This article explores the role that scientific information can play in improving implementation of National Ambient Air Quality Standards and discusses some of the key policy-relevant questions related to implementation that could be informed by advances in the scientific research. This article expands on the concept of urban exposure environments as useful constructs in helping to improve research into the roles of air pollution mixtures and population exposure patterns in air pollution health effects. Recommendations for potential research areas related to urban exposure environments are discussed, including (1) improving the understanding of the role that individual pollutants play within the overall mixture of pollutants that determine air quality and health outcomes in an urban area, (2) understanding the causes of heterogeneity (or similarity) across urban areas in the relative risks associated with air pollution, and (3) improving air quality characterization within urban exposure environments, recognizing the complex air pollution mixtures in many environments which may result from emissions from multiple sources, including regional and local contributors. Informed implementation policies focused on multipollutant risk-based management objectives guided by an improved understanding of multipollutant exposures are likely to lead to greater improvements in public health through more effective and efficient emissions controls.     

Ambient air quality programmes for health impact assessment in the WHO European region

An important aim of air quality assessment is to provide information about population exposure and health impact assessment. Numerous epidemiological studies have already shown that exposure to excessive levels of ambient air pollutants are associated with either acute or chronic health effects. Until recently, the adequacy of monitoring population exposure in relation to quantitative assessment of health effects of air pollution was rarely considered in ambient air monitoring strategies. This made the formulation of health-related recommendations to risk management difficult and weakens preventive and other measures to reduce adverse health effects of air pollution. To improve local and national capacities for health impact assessment, the European Centre for Environment and Health of the World Health Organization has prepared methodology guidelines concerning selected aspects of air monitoring. The WHO Collaborating Centre for Air Quality Management and Air Pollution Control support efforts in line with international programmes on quality assurance and control for Europe.     

Polluted air--outdoors and indoors

Many air pollutants which are considered important in ambient (outdoor) air are also found, sometimes at higher levels, in indoor air. With demanding standards having been set for many of these pollutants, both in the workplace and ambient air, consideration of the problems posed by indoor pollution is gaining pace. Studies on exposure to pollutants found in the indoor domestic environment are increasing and are contributing to an already significant compilation of datasets. Improvement in monitoring techniques has helped this process. Documented reports of fatalities from carbon monoxide poisonings are still worrying. However, studies on health effects of non-fatal, long term, low dose, indoor exposure to carbon monoxide and other pollutants, are still inconclusive and too infrequently documented. Of particular concern are the levels of air pollutants found in the domestic indoor environment in developing countries, despite simple interventions such as vented stoves having shown their value. Exposure to biomass smoke is still a level that would be considered unacceptable on health grounds in developed countries. As in the occupational environment, steps need to be taken to control the risks from exposure to the harmful constituents of indoor air in the home. However, the difficulty regarding regulation of the domestic indoor environment is its inherent privacy. Monitoring levels of pollutants in the home and ensuring regulations are adhered to, would likely prove difficult, especially when individual behaviour patterns and activities have the greatest influence on pollutant levels in indoor air. To this end, the Department of Health is developing guidance on indoor air pollution to encourage the reduction of pollutant levels in indoor domestic air. The importance of the effects of domestic indoor air on health and its contribution to the health of the worker are increasingly appreciated. Occupational physicians, by training and interest, are well placed to extend their interests into the environmental field and to focus on this important area.     

Reducing burden of disease from residential indoor air exposures in Europe (HEALTHVENT project)

Background

The annual burden of disease caused indoor air pollution, including polluted outdoor air used to ventilate indoor spaces, is estimated to correspond to a loss of over 2 million healthy life years in the European Union (EU). Based on measurements of the European Environment Agency (EEA), approximately 90 % of EU citizens live in areas where the World Health Organization (WHO) guidelines for air quality of particulate matter sized?<?2.5 mm (PM_2.5) are not met. Since sources of pollution reside in both indoor and outdoor air, selecting the most appropriate ventilation strategy is not a simple and straightforward task.

Methods

A framework for developing European health-based ventilation guidelines was created in 2010–2013 in the EU-funded HEALTHVENT project. As a part of the project, the potential efficiency of control policies to health effects caused by residential indoor exposures of fine particulate matter (PM_2.5), outdoor bioaerosols, volatile organic compounds (VOC), carbon oxide (CO) radon and dampness was estimated. The analysis was based on scenario comparison, using an outdoor-indoor mass-balance model and varying the ventilation rates. Health effects were estimated with burden of diseases (BoD) calculations taking into account asthma, cardiovascular (CV) diseases, acute toxication, respiratory infections, lung cancer and chronic obstructive pulmonary disease (COPD).

Results

The quantitative comparison of three main policy approaches, (i) optimising ventilation rates only; (ii) filtration of outdoor air; and (iii) indoor source control, showed that all three approaches are able to provide substantial reductions in the health risks, varying from approximately 20 % to 44 %, corresponding to 400 000 and 900 000 saved healthy life years in EU-26. PM_2.5 caused majority of the health effects in all included countries, but the importance of the other pollutants varied by country.

Conclusions

The present modelling shows, that combination of controlling the indoor air sources and selecting appropriate ventilation rate was the most effective to reduce health risks. If indoor sources cannot be removed or their emissions cannot be limited to an accepted level, ventilation needs to be increased to remove remaining pollutants. In these cases filtration of outdoor air may be needed to prevent increase of health risks.

     

室内空气污染物及其健康效应研究

随着人们生活质量的提高，室内空气污染越来越受到关注。由于室内空气污染导致的不良建筑物综合症(sick building syndrome，SBS)已经成为现代人生活中不可忽视的一个问题，室内空气污染已经被列为对公众健康危害最大的5种环境因素之一。笔者对影响室内空气质量的几种重要气态污染物(甲醛、氡气、氨气、氮氧化物以及挥发性有机物等)，就其健康效应及其近几年的研究进展进行综述，并指出了今后的研究重点和方向。     

Comments on studies of industrial and non-industrial environments in Brazil: a comparative approach

Air quality in industrial environments has been studied since the second half of the 20th century. Well-documented results show that exposure to chemical pollutants through their consumption, production, and storage can damage workers' health. New research focusing on non-industrial environments has shown unexpected correlations between air quality and health effects. Artificial ventilation systems have been related to health-related complaints and a high rate of absenteeism. Symptoms related to air quality in non-industrial environments are recognized by the World Health Organization and encompassed under the so-called sick building syndrome (SBS). In Brazil there are few studies comparing indoor air quality and health. The present study is intended to map the studies already conducted in Brazil in order to encourage further research in this area, due to its importance for public health.     

南宁市新装修居室空气污染状况及其对人群健康的影响

目的了解南宁市新装修居室空气污染状况及其对人体健康的影响。方法按照GB/T18883—2002《室内空气质量标准》对南宁市2002—2006年130户新装修居室内空气中甲醛、苯、甲苯、二甲苯和放射性水平进行检测;对25户室内空气中甲醛浓度超标的居室进行跟踪检测,并对居民健康状况进行问卷调查。结果130户新装修居室空气样本甲醛浓度合格率为25.6%,氨浓度合格率为27.1%,平均浓度超标倍数分别为3.88倍和1.35倍;而放射性水平及苯、甲苯、二甲苯浓度合格率分别为99.6%,97.6%,89.5%,91.9%。25户室内空气甲醛浓度超标居室入住6～12个月后空气甲醛浓度低于人住时(P<0.01)。健康状况问卷调查结果显示,居民入住时均有不同程度的不良反应出现,其中以咽喉疼痛的发生率最高,达92%。结论甲醛和氨是南宁市新装修居室环境中最主要的污染物,新装修居室空气污染已对人体健康产生一定程度的影响。     

Could portable powered respirators help us avoid the exposure to air pollution?

Atmospheric pollution has become a persistent threat to human health. Consequently, the effects of breathing polluted air in large cities are being assessed for given risk groups and different indoor and outdoor activities. This work delves into the study of the possibility to develop individual portable air-purifying respirators to avoid the exposure to atmospheric pollution when carrying out common daily activities at home or outdoors. Samples of known concentrations of the criteria pollutants (except for lead) have been monitored before and after passing through a powered occupational respirator which has been also tested carrying out physical activities mainly under outdoor conditions. The results show that the system is not effective against carbon monoxide but it does provide protection against particulate matter, SO₂, NO_x, O₃, and volatile organic compounds, that is, most of the main pollutants found in outdoor air. Thus, individual powered respirators are technologically viable based on the current occupational devices and by providing them with additional suggested improvements. Being affordable, this kind of systems may become very helpful not only for assistive applications but also for healthy people willing to reduce exposure to air pollution.     

Health effects from indoor air pollution: Case studies

In recent years there has been a growing awareness of the health effects associated with the presence of contaminants in indoor air. Numerous agents can accumulate in public buildings, homes and automobiles as a result of ongoing activities that normally occur in these closed spaces. Ventilation is a major factor in the control of indoor air pollutants since proper movement of air can prevent or minimize the build up of compounds in buildings. The recent emphasis on energy conservation has lead to measures which economize on energy for heating and air conditioning, but which also trap pollutants within a building. Three cases of indoor air pollution were investigated. A typical investigation of indoor air pollutant problems includes the following: 1) interviews with building occupants; 2) history of the building with regard to maintenance, pesticide treatment, etc.; 3) a survey of the building and ventilation; and when warranted, 4) sampling and analysis of air. Each case presented is unique in that atypical situations caused agents to accumulate in a building or section of a building. The indoor air problems in these cases were solved by identifying and removing the source of the offending agent and/or improving the ventilation in the building.LuAnn E. White, Ph.D., DABT is Associate Professor Department of Environmental Health Sciences Tulane University School of Public Health and Tropical Medicine 1501 Canal Street New Orleans, Louisiana, 70112. Jacqueline R. Clarkson, MSPH is with the Louisiana Department of Health and Human Resources P.O. Box 60630 New Orleans, Louisiana, 70160. Shau-Nong Chang, Ph.D., CIH is Assistant Professor, Department of Environmental Health Sciences Tulane University School of Public Health and Tropical Medicine 1501 Canal Street New Orleans, Louisiana, 70112.     

Indoor and outdoor air pollution: tobacco smoke, moulds and diseases in infants and children

Although outdoor air pollution first brought the issue of air pollution health effects to public attention, it is now indoor air pollution that likely has the greatest impact on children's health. The World Health Organization estimates that the global burden of disease from indoor air pollution is far greater than the burden from outdoor air pollution. This review focuses on two indoor pollutants, one that has been well studied, and another that deserves additional study. There is very strong evidence about the harmful effects of tobacco. Policy to decrease children's tobacco exposure and use should be implemented without delay. The emerging findings linking household inhalation of mould spores and infant pulmonary hemorrhage merit follow-up in other countries, because they may provide clues to some deaths from the sudden infant death syndrome.     

“Air pollution in Delhi: Its Magnitude and Effects on Health”

Air pollution is responsible for many health problems in the urban areas. Of late, the air pollution status in Delhi has undergone many changes in terms of the levels of pollutants and the control measures taken to reduce them. This paper provides an evidence-based insight into the status of air pollution in Delhi and its effects on health and control measures instituted. The urban air database released by the World Health Organization in September 2011 reported that Delhi has exceeded the maximum PM10 limit by almost 10-times at 198 μg/m3. Vehicular emissions and industrial activities were found to be associated with indoor as well as outdoor air pollution in Delhi. Studies on air pollution and mortality from Delhi found that all-natural-cause mortality and morbidity increased with increased air pollution. Delhi has taken several steps to reduce the level of air pollution in the city during the last 10 years. However, more still needs to be done to further reduce the levels of air pollution.     

Indoor environments and health: moving into the 21st century

The quality of our indoor environments affects well-being and productivity, and risks for diverse diseases are increased by indoor air pollutants, surface contamination with toxins and microbes, and contact among people at home, at work, in transportation, and in many other public and private places. We offer an overview of nearly a century of research directed at understanding indoor environments and health, consider current research needs, and set out policy matters that need to be addressed if we are to have the healthiest possible built environments. The policy context for built environments extends beyond health considerations to include energy use for air-conditioning, selection of materials for sustainability, and design for safety, security, and productivity.     

Pollution of room air

In the last decade the significance of indoor air pollution to human health has increased because of improved thermal insulation of buildings to save energy: air turnover is reduced and air quality is impaired. The most frequent air pollutants are tobacco smoke, radioactive radon gas emanating from the soil, formaldehyde from furniture and insulation material, nitrogen oxides from gas stoves, as well as solvents from cleaning agents. The most important pollutants leading to health hazards are tobacco smoke and air pollutants which are emitted continuously from building materials and furniture. Such pollutants have to be eliminated by reducing the emission rate. A fresh air supply is necessary to reduce the pollutants resulting from the inhabitants and their activities, the amount depending on the number of inhabitants and the usage of the room. The carbon dioxide level should not exceed 1500 ppm.     

Sampling strategy and analytical problems in work environments

The paper reviews the problems involved in sampling and analysis of pollutants in working environments. Special attention is given to the practical consequences of the particular working conditions of to-day, which are characterized by low levels of environmental pollution but are at the same time subject to the presence of mixtures of chemical substances. There is no doubt that the time has come to attempt to reach the greatest possible consensus on these problems (e.g., analytical procedures for complex mixtures). Guidelines and procedures are indicated for the control of indoor pollution and indoor air quality limits are proposed both for long-term (ALTER) and short-term (ASTER) exposures.     

Feasibility of assessing public health impacts of air pollution reduction programs on a local scale: New Haven case study

Background

New approaches to link health surveillance data with environmental and population exposure information are needed to examine the health benefits of risk management decisions.

Objective

We examined the feasibility of conducting a local assessment of the public health impacts of cumulative air pollution reduction activities from federal, state, local, and voluntary actions in the City of New Haven, Connecticut (USA).

Methods

Using a hybrid modeling approach that combines regional and local-scale air quality data, we estimated ambient concentrations for multiple air pollutants [e.g., PM_2.5 (particulate matter ≤ 2.5 μm in aerodynamic diameter), NO_x (nitrogen oxides)] for baseline year 2001 and projected emissions for 2010, 2020, and 2030. We assessed the feasibility of detecting health improvements in relation to reductions in air pollution for 26 different pollutant–health outcome linkages using both sample size and exploratory epidemiological simulations to further inform decision-making needs.

Results

Model projections suggested decreases (~ 10–60%) in pollutant concentrations, mainly attributable to decreases in pollutants from local sources between 2001 and 2010. Models indicated considerable spatial variability in the concentrations of most pollutants. Sample size analyses supported the feasibility of identifying linkages between reductions in NO_x and improvements in all-cause mortality, prevalence of asthma in children and adults, and cardiovascular and respiratory hospitalizations.

Conclusion

Substantial reductions in air pollution (e.g., ~ 60% for NO_x) are needed to detect health impacts of environmental actions using traditional epidemiological study designs in small communities like New Haven. In contrast, exploratory epidemiological simulations suggest that it may be possible to demonstrate the health impacts of PM reductions by predicting intraurban pollution gradients within New Haven using coupled models.     

Reducing Health Risks from Indoor Exposures in Rapidly Developing Urban China

Background: Over the past two decades there has been a large migration of China’s population from rural to urban regions. At the same time, residences in cities have changed in character from single-story or low-rise buildings to high-rise structures constructed and furnished with many synthetic materials. As a consequence, indoor exposures (to pollutants with outdoor and indoor sources) have changed significantly.Objectives: We briefly discuss the inferred impact that urbanization and modernization have had on indoor exposures and public health in China. We argue that growing adverse health costs associated with these changes are not inevitable, and we present steps that could be taken to reduce indoor exposures to harmful pollutants.Discussion: As documented by China’s Ministry of Health, there have been significant increases in morbidity and mortality among urban residents over the past 20 years. Evidence suggests that the population’s exposure to air pollutants has contributed to increases in lung cancer, cardiovascular disease, pulmonary disease, and birth defects. Whether a pollutant has an outdoor or an indoor source, most exposure to the pollutant occurs indoors. Going forward, indoor exposures can be reduced by limiting the ingress of outdoor pollutants (while providing adequate ventilation with clean air), minimizing indoor sources of pollutants, updating government policies related to indoor pollution, and addressing indoor air quality during a building’s initial design.Conclusions: Taking the suggested steps could lead to significant reductions in morbidity and mortality, greatly reducing the societal costs associated with pollutant derived ill health.     

三门峡市室内装修污染调查分析

目的了解室内装修污染物，适时开展室内空气质量检测控制。方法依据《室内空气质量标准》对市区装修后的82户居民的246个居室室内空气质量进行调查检测。结果甲醛、苯为室内装修主要污染物，甲醛总体超标率79．3％，室内温度每升高5℃，甲醛浓度增加1．3～1．5倍；不同装修类型甲醛浓度差异有显著意义（P〈0．05）。结论甲醛和笨系物是装修主要污染物；每年二、三季度有利于室内空气质量检测，应注重室内装修甲苯、二甲苯检测。