Search

Background. Air pollution is an important issue in developed and industrialized countries. The most common sources of air pollution are anthropogenic activities such as construction dust, vehicular emissions and mining. For low- and middle-income countries, biomass burning and indoor heating are the leading sources of air pollution. As more of the world undergoes development and human populations increase, industrialization is also increasing, along with the potential for air pollution. Objectives. This article reviews the status of air pollution to raise awareness of air quality and human health in Botswana. Discussion. Since independence, Botswana has experienced one of the highest economic development growth rates in the world. These changes have occurred as a result of economic growth and resource utilization associated with increased industrialization. However, there is growing worldwide concern about the effect and impact of pollution due to industrial growth. Botswana is ranked amongst the most polluted countries with serious air pollution, despite a population of just over 2 million. Conclusions. Rapid development and increased urbanization have had a major environmental impact around the world. This increased growth has the potential to lead to air quality degradation. Significant health threats are posed by industrial and vehicular emissions, especially in urban and peri-urban areas where the population is most concentrated. It is important that the linkage between air pollution and health effects is fully examined across all scales of life, especially in developing countries. In addition, programs should be devised to educate the public about the pollution impacts on health. Competing Interests: The authors declare no financial competing interests.

Two rural communities using fuel wood energy in mountainous and coastal areas of Java island in Indonesia have been surveyed to know their household characteristics and the related potential indoor air pollution issues. By random sampling, we characterized fuel wood users only. The fuel wood use was mainly due to economic reason since some of the users were categorized as low-income families. Communities in the mountainous area were exposed to higher risk of indoor air pollution than those in coastal area due to their house characteristics and behavior during cooking. Both communities, however, were aware of indoor air pollution issues and indicated the sources. They also prioritized the factors to be controlled, which they perceived as the main cause of indoor air pollution problem.

The deleterious effects of ambient air pollution on human health have been consistently documented by many epidemiologic studies worldwide, and it has been calculated that globally at least seven million deaths are annually attributable to the effects of air pollution. The major air pollutants emitted into the atmosphere by a number of natural processes and human activities include nitrogen oxides, volatile organic compounds, and particulate matter. In addition to the poor ambient air quality, there is increasing evidence that indoor air pollution also poses a serious threat to human health, especially in low-income countries that still use biomass fuels as an energy resource. This review summarizes the current knowledge on ambient air pollution in financially deprived populations.

Almost three billion people worldwide use biomass and coal as their primary source of energy for cooking, heating, and other household needs. Combustion of biomass and coal emits hundreds of health-damaging pollutants, at concentrations several fold higher than common health guidelines, especially when used in open or poorly enclosed and ventilated stoves. An estimated 1.8 million annual deaths and 3% of the total global burden of disease are due to exposure to indoor air pollution from solid fuels, mainly among young children and adult women. There is a need for ambitious R&D on alternative technologies for clean and accessible energy, and on economic and regulatory institutions required for large-scale dissemination of these technologies.

Though the high prevalence of biomass fuel use in the developing world is widely known, the use of burning biomass for cooking and heating in the developed world is under-recognized. Combustion materials including coal and wood are also used for heating in some areas of the United States. We conducted a pilot study to assess the feasibility of conducting indoor environmental monitoring in rural Appalachia. We sought to explore the type of biomass being used for home heating and its impact upon indoor air quality in non-heating and heating seasons. Residential indoor air monitoring for particulate matter (PM) and nitrogen dioxide (NO2) was conducted in Lee County, Virginia. Homes had evidence of poor indoor air quality with high concentrations of indoor PM and a large burden of cigarette smoking. Further characterization of indoor combustion material use in this region to determine the health impacts associated with such exposures is warranted.

Background Nearly 3 billion people live without electricity today. This energy poverty means that they have to resort to biomass fuels for their household energy needs. When burned, these fuels release a mixture of toxic chemicals in their smoke, which is often over twenty times greater than World Health Organization (WHO) and Environmental Protection Agency recommended guideline limits.

Air pollution is increasingly recognized as a significant contributor to global health outcomes. A methodological framework for evaluating the global health-related outcomes of outdoor and indoor (household) air pollution is presented and validated for the year 2005. Ambient concentrations of PM2.5 are estimated with a combination of energy and atmospheric models, with detailed representation of urban and rural spatial exposures. Populations dependent on solid fuels are established with household survey data. Health impacts for outdoor and household air pollution are independently calculated using the fractions of disease that can be attributed to ambient air pollution exposure and solid fuel use. Estimated ambient pollution concentrations indicate that more than 80% of the population exceeds the WHO Air Quality Guidelines in 2005. In addition, 3.26 billion people were found to use solid fuel for cooking in three regions of Sub Saharan Africa, South Asia and Pacific Asia in 2005. Outdoor air pollution results in 2.7 million deaths or 23 million disability adjusted life years (DALYs) while household air pollution from solid fuel use and related indoor smoke results in 2.1 million deaths or 41.6 million DALYs. The higher morbidity from household air pollution can be attributed to children below the age of 5 in Sub Saharan Africa and South Asia. The burden of disease from air pollution is found to be significant, thus indicating the importance of policy interventions.

The health and climate impacts of available household cooking options in developing countries vary sharply. Here, we analyze and compare these impacts (health; climate) and the potential co-benefits from the use of fuel and stove combinations. Our results indicate that health and climate impacts span 2 orders of magnitude among the technologies considered. Indoor air pollution is heavily impacted by combustion performance and ventilation; climate impacts are influenced by combustion performance and fuel properties including biomass renewability. Emission components not included in current carbon trading schemes, such as black carbon particles and carbon monoxide, can contribute a large proportion of the total climate impact. Multiple ‘improved’ stove options analyzed in this paper yield roughly equivalent climate benefits but have different impacts on indoor air pollution. Improvements to biomass stoves can improve indoor air quality, which nonetheless remains significantly higher than for stoves that use liquid or gaseous hydrocarbons. LPG- and kerosene-fueled stoves have unrivaled air quality benefits and their climate impacts are also lower than all but the cleanest stoves using renewable biomass. & 2011 Elsevier Ltd. All rights reserved.

In European countries and North America, people spend 80 to 90% of time inside buildings and thus breathe indoor air. In Switzerland, special attention has been devoted to the 16 stations of the national network of observation of atmospheric pollutants (NABEL). The results indicate a reduction in outdoor pollution over the last ten years. With such a decrease in pollution over these ten years the question becomes: how can we explain an increase of diseases? Indoor pollution can be the cause. Indoor contaminants that may create indoor air quality (IAQ) problems come from a variety of sources. These can include inadequate ventilation, temperature and humidity dysfunction, and volatile organic compounds (VOCs). The health effects from these contaminants are varied and can range from discomfort, irritation and respiratory diseases to cancer. Among such contaminants, environmental tobacco smoke (ETS) could be considered the most important in terms of both health effects and engineering controls of vent...

In recent years, air pollution has become a critical social problem because harmful materials can cause disease and death to humans as well as damage to other living organisms, including food crops, or the natural or built environment. In 2014, the World Health Organization (WHO) reported that around 7 million people died in 2012 as a result of exposure to air pollution, that is, one in eight of total global deaths, which indicates that air pollution is now the world's largest single environmental health risk [1, 2]. WHO also estimates that indoor air pollution in households cooking over coal, wood and biomass stoves was linked to 4.3 million deaths. In the case of outdoor air pollution, WHO estimates that 3.7 million deaths worldwide occurred as a result of sources of pollution from both urban and rural areas.

The rapid economic development occurring in developing countries in recent decades has been accompanied with increasingly worsened air quality. In recent years, severe air pollution episodes have occurred frequently in the cities of some developing countries. The goal of this chapter is to describe outdoor air pollution issues with a focus on urban areas in developing countries. Topics include global air pollution trends, differences in emissions and concentrations of key air pollutants in different regions, emission sources disproportionately affecting developing countries, estimating disease burden in developing countries, and recommendations based on historical successes and lessons from developed countries.

Indoor air pollution (IAP) due to daily household cooking with unprocessed solid biomass such as wood, dung and crop residues is a serious health hazard in the poor, developing countries of Asia, sub-Saharan Africa and Latin America. Globally, 2.8 billion people use biomass for domestic energy. Incomplete combustion of biomass emits smoke that contains a host of potentially health-damaging particulate and gaseous pollutants, some of which like benzo(a)pyrene, 1,3-butadiene and benzene are known human carcinogens. IAP from biomass burning is responsible for excess mortality and morbidity. An estimated four million deaths, mostly from cardio-pulmonary causes, have been attributed to biomass use. Children, women and the elderly people are most vulnerable. Chronic inhalation of biomass smoke induces lung function decrement, increases the risk of life-threatening chronic obstructive pulmonary disease, evokes pulmonary and systemic inflammation and consequent oxidative stress, and contributes to the development of hypertension and cardio-vascular diseases. Daily household cooking with biomass was associated with higher incidences of anemia, platelet hyperactivity, and altered number and activities of the immune cells. Oxidative stress generated by biomass smoke mediates chromosomal and DNA damage and impairment in DNA repair mechanism in the exposed cells. In addition, chronic inhalation of biomass smoke up-regulates protein kinase B/Akt signaling and metaplasia and dysplasia of airway cells, implying increased risk of lung cancer. Women who cooked with biomass also had altered serotonergic activity with greater prevalence of depression. Thus, IAP due to household cooking with biomass adversely affects both physical and mental health of the people.

Solid fuels are a major source of indoor air pollution, but in less developed countries the short-term health effects of indoor air pollution are poorly understood. The authors conducted a large cross-sectional study of rural Chinese households to determine associations between individual health status and domestic cooking as a source of indoor air pollution. The study included measures of health status as well as measures of indoor air-pollution sources, such as solid cooking fuels and cooking stoves. Compared with other fuel types, coal was associated with a lower health status, including negative impacts on exhaled carbon monoxide level, forced vital capacity, lifetime prevalence of chronic obstructive pulmonary disease and asthma, and health care utilization. Decreasing household coal use, increasing use of improved stove technology, and increasing kitchen ventilation may decrease the short-term health effects of indoor air pollution.

Air pollution remains a major threat to children’s health. In high-income countries, most outdoor air pollution is from fossil fuel combustion, and most indoor pollution is from cooking and environmental tobacco smoke (ETS). Outdoor pollution in medium- and low-income countries is a mix of fossil-fuel, solid fuel (e.g. coal) and biomass (wood), and indoor pollution is from biomass smoke, solid fuels and ETS. Over the last decade, new data suggest that both biomass smoke and ETS increases the vulnerability of children to bacterial pneumonia, and that fossil-fuel and biomass smoke impair children’s neurocognitive development. Further research is needed to establish biological plausibility for these associations.

Globally, almost 3 billion people rely on biomass (wood, charcoal, crop residues, and dung) and coal as their primary source of domestic energy. Exposure to indoor air pollution (IAP) from the combustion of solid fuels is an important cause of morbidity and mortality in developing countries. In this paper, we review the current knowledge on the relationship between IAP exposure and disease and on interventions for reducing exposure and disease. We take an environmental health perspective and consider the details of both exposure and health effects that are needed for successful intervention strategies. We also identify knowledge gaps and detailed research questions that are essential in successful design and dissemination of preventive measures and policies. In addition to specific research recommendations, we conclude that given the interaction of housing, household energy, and day-to-day household activities in determining exposure to indoor smoke, research and development of effective interventions can benefit tremendously from integration of methods and analysis tools from a range of disciplines in the physical, social, and health sciences.

It has recently been estimated that 4 million deaths each year are associated with air pollution originating from household solid fuel use. Interventions to reduce biomass fuel-related emis- sions can yield a diverse stream of benefits including improved public health, socio-economic development, reduced land degradation and climate change mitigation. This study investigates the use of indigenous knowledge to inform interventions to combat indoor air pollution at a rural site in the Punjab province of Pakistan. The results indicate that the majority of people using biomass fuel had knowledge of its ill health effects. A range of methods were utilised to reduce indoor smoke including included cooking in open spaces, use of chimneys, better ventilation and use of dry fuel. Education and housing type showed a statistically significant relationship with awareness of methods to reduce indoor exposure to biomass smoke. These findings lend support to the notion that communities have indigenous knowledge and their own methods to reduce exposure to indoor smoke from biomass fuels; this knowledge can be used as tool to design and implement sustainable intervention strategies to reduce the risk of exposure to indoor air pollution. It is recommended that a community based intervention focusing on locally manufactured improved stoves and better designed cooking spaces would be a suitable intervention in this region.

This article is a revision of the previous edition article by Dieter Schwela, Dimitrios Kotzias, volume 3, pp 475–489, © 2005, Elsevier Inc.

In the last decade, a number of quantitative epidemiological studies of specific diseases have been done in developing countries that for the first time allow estimation of the total burden of disease (mortality and morbidity) attributable to use of solid fuels in adult women and young children, who jointly receive the highest exposures because of their household roles. Few such studies are available as yet for adult men or children over 5 years. This paper evaluates the existing epidemiological studies and applies the resulting risks to the more than three-quarters of all Indian households dependent on such fuels. Allowance is made for the existence of improved stoves with chimneys and other factors that may lower exposures. Attributable risks are calculated in reference to the demographic conditions and patterns of each disease in India. Sufficient evidence is available to estimate risks most confidently for acute respiratory infections (ARI), chronic obstructive pulmonary disease (COPD), and lung cancer. Estimates for tuberculosis (TB), asthma, and blindness are of intermediate confidence. Estimates for heart disease have the lowest confidence. Insufficient quantitative evidence is currently available to estimate the impact of adverse pregnancy outcomes (e.g., low birthweight and stillbirth). The resulting conservative estimates indicate that some 400–550 thousand premature deaths can be attributed annually to use of biomass fuels in these population groups. Using a disability-adjusted lost life-year approach, the total is 4–6% of the Indian national burden of disease, placing indoor air pollution as a major risk factor in the country.

Objectives : To examine the relation between use of biomass cooking fuels (wood or dung) and prevalence of active tuberculosis in India. Methods: The analysis is based on 260,162 persons age 20 and over in India's 1992–1993 National Family Health Survey. Logistic regression is used to estimate the effects of biomass fuel use on prevalence of active tuberculosis, as reported by household heads, after controlling for a number of potentially confounding variables. Results: Persons living in households that primarily use biomass for cooking fuel have substantially higher prevalence of active tuberculosis than persons living in households that use cleaner fuels (odds ratio [OR] = 3.56; 95% confidence interval [Cl] = 2.82−4.50). This effect is reduced somewhat when availability of a separate kitchen, house type, indoor crowding, age, gender, urban or rural residence, education, religion, caste or tribe, and geographic region are statistically controlled (OR = 2.58; 95% Cl=1.98−3.37). Fuel type also has a large effect when the analysis is done separately for men (OR = 2.46; 95% Cl=1.79−3.39) and women (OR = 2.74; 95% Cl=1.86−4.05) and separately for urban areas (OR = 2.29; 95% Cl=1.61−3.23) and rural areas (OR = 2.65; 95% Cl=1.74−4.03). The analysis also indicates that, among persons age 20 years and over, 51% of the prevalence of active tuberculosis is attributable to cooking smoke. Conclusions: Results strongly suggest that use of biomass fuels for cooking substantially increases the risk of tuberculosis in India.

In the study by Guarnieri et al1 in this issue of CHEST (see page 1184), the authors reported no evidence for an association between lung function and early randomization to a chimney stove intervention. These findings prompted the authors to conclude that future studies may need to incorporate cleaner stoves or cleaner fuels.1 Personal carbon monoxide (CO) exposures in the chimney woodstoves used in their study were only reduced by 30% following stove installation, while other chimney stoves, such as Patsari (Grupo Interdisciplinario de Tecnología Rural Apropiada), reduce personal exposures to CO by 78%.2 Using the Patsari stove model, Romieu et al3 reported a significantly lower FEV1 decline (31 mL) compared with open fire use (62 mL) over 1 year of follow-up (P = .012) for women 20 years of age and older. Zhou et al4 found less deterioration in FEV1 of 12, 13, and 16 mL/y in those who used biogas, improved ventilation, or both, respectively, compared with those who took up neither intervention, after adjustment for confounders. The longer the duration of improved fuel use and ventilation, the greater the benefits in slowing the decline of FEV1 (P < .05)...

Indoor air pollution represents a global health crisis, leading to 4.3 million deaths annually. Despite widespread variation in solid fuel burning across developing nations, little is known about the large scale socio-economic causes. We draw on theories of political-economy to consider the role of economic, social, and environmental predictors on solid fuel use, with a special focus on structural adjustment, debt service, and agricultural production. Utilizing a sample of 75 developing nations, we find that these economic dependencies increase solid fuel use. Thus, current neoliberal development strategies enhance vulnerabilities to indoor air pollution for millions of people in impoverished nations.

Cooking with solid fuels on open fires or traditional stoves creates high levels of indoor air pollution, which is a major risk factor for pneumonia among children and chronic respiratory disease among adults. Indoor smoke contains many pollutants that can damage health, such carbon monoxide and particulate pollution levels that may be 20 times higher than accepted guidelines. This problem can be overcome by using improved stoves with ventilation and exhaust chimneys to some extent. Using bio gas and solar energy for cooking purpose will be more effective.

Anthropogenic air pollution has affected the environment since the development of the first human communities. Today, pollution arises due to the burning of wood, vegetation, coal, natural gas, oil, gasoline, kerosene, diesel, liquid biofuels, waste, and chemicals. Two general types of urban-scale pollution were identified in the twentieth century: London-type smog and photochemical smog. The former results from the burning of coal and other raw materials in the presence of a fog or strong temperature inversion, and the latter results from the emission of hydrocarbons and oxides of nitrogen in the presence of sunlight. In most places, urban air pollution consists of a combination of the two. In this chapter, urban outdoor gas-phase air pollution is discussed in terms of its history, early regulation, and chemistry. History and Early Regulation of Outdoor Urban Air Pollution Before the twentieth century, air pollution was treated as a regulatory or legal problem rather than a scientific problem. Because regulations were often weak or not enforced and health effects of air pollution were not well understood, pollution problems were rarely mitigated. In this section, a brief history of air pollution and its regulation until the 1940s is discussed.

The indoor environment is an important determinant of health as humans typically spend 90% of their time indoors. Indoor air pollution attributed to solid fuel combustion products from heating and cooking is a major public health challenge mostly throughout the developing world. Solid fuel consists of coal and various forms of biomass, such as wood, crops, and dung. In general, the most frequently utilized domestic fuel in China is coal. As for Africa and India, biomass fuel sources are typically used. The use of these fuels in poor and no-ventilation situations is worrisome as the attributed smoke has been associated with a variety of cancers, the most notable being lung cancer. Indoor emissions from household combustion of coal have been classified as a human carcinogen, whereas biomass combustion emissions have been classified as probably carcinogenic to humans. Further research is needed to elucidate the potential modification of the coal use and lung cancer association by genetic variation and the varying carcinogenic potential of coal subtypes. Additional studies evaluating the association between cancer risk and wood use are also warranted.

Mitigation and control of air pollution depend on our endeavor and focus on the sources of concern. Households in vast number of countries of the developing world depend on biomass fuel (wood, dung, and agricultural residues) and coal as their basic source of energy needs of daily life, for cooking, lighting, and climatic controls. Concerns have been raised about the emissions of pollutants from the combustion of solid biomass fuels, solid waste, coal, vegetation, and forest fire. These combustions produce air pollutants including organic, inorganic, and particulate matters. The population directly exposed to such polluting environment are at risk of health impacts, for example, acute respiratory infections (ARI), chronic obstructive pulmonary disease (COPD), asthma, tuberculosis, lung cancer (from coal smoke), cancer of the nasopharynx and larynx, including perinatal conditions and low birth weight, cardiovascular disease, cataract, and blindness.

........ .. .. . ...... . . ....... ....... ... .... 529 INTRODUCTION ' . . . . . . . . . . . . . . . . . . . . . . . . . . . 530 WHERE IS AIR POLLUTION? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 531 An Example of the Power of Exposure Assessment: Coal Versus Tobacco . . . . 535 Exposure Effectiveness . . . . . .. ....... 538 GLOBAL EXPOSURE ASSESSMENT ...... .... .... ...... ........ 539 Where, Then, Are the People? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 539 Exposure Analysis ...... . . . ... ... ... ..... . .... .. . ... ..... 541 Trends During Development .... ...... ... .... . .. .... . .. ... ... 549 HEALTH EFFECTS .. ... .. . ... ......... . . ..... ... 55 1 Rural Indoor Exposures ... ... .... ... ... .. ..... ... . . . ..... .. 551 Urban Indoor Exposures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 555 Urban Outdoor Exposures. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 555 CONCLUSION . . . . . . . . . . . . . . . . . . . . .. . . . . . .. . . . . . . . . . . . . . . 558 APPENDIX: INTERNATIONAL URBAN AIR POLLUTION STUDIES ... .... 561

Most of the literature on indoor air quality deals with the problems of the affluent western world, such as the optimal working of HVAC systems and limiting the emissions of potentially toxic mater...

Indoor air pollution (IAP) is an important cause of morbidity and mortality throughout the world. But its severity is much more in the developing countries due to burning of traditional biomass fuels such as wood, animal dung, and crop residues for daily domestic cooking in rural households. Indeed, smoke exposure from biomass burning is regarded as one of the most serious environmental problems facing the developing countries throughout the world (World Bank, 1992; Smith and Mehta, 2000). It is estimated that IAP from biomass burning is responsible for 4% of the global burden of disease (Bruce et al., 2000), and a conservative estimate indicates that the practice of biomass fuel use endangers the health of 400-700 million people across the globe and causes 2.8 million premature deaths every year (Bruce et al., 2000). It affects especially the women and children who spend long hours inside the cooking areas (Larson and Rosen, 2002). As in many other developing countries, biomass fuel is still extensively being used in rural households of India for daily household cooking as well as for room heating in hilly areas. There have been some studies on the effects of biomass use on respiratory health of rural women in India, but the overall impact of biomass fuel use on public health, especially that of women and children in rural areas of the country, is yet to be elucidated. In this chapter, we have collated the published reports on health impact of IAP from biomass fuel use in India and elsewhere. In addition, we have incorporated some important ndings from our ongoing investigation on respiratory and general health impairments of women in rural areas of West Bengal, a state in Eastern India. We have included the ndings of 1260 women (median age 38 years) who cook with biomass regularly for the past ve years or more and have compared these results with that of 650 liquid petroleum gas (LPG)-using women from similar neighborhood matched for age (median age 37 years), tobacco smoking and chewing habits, and body mass index.

Approximately half of the world's population relies on biomass (primarily wood and agricultural residues) or coal fuels (collectively termed solid fuels) for heating, lighting, and cooking. The incomplete combustion of such materials releases byproducts with well-known adverse health effects, hence increasing the risk of many diseases and death. Among these conditions are acute respiratory infections, chronic obstructive pulmonary disease, heart disease, stroke, lung cancer, cataracts and blindness, tuberculosis, asthma, and adverse pregnancy outcomes. The International Agency for Research on Cancer has classified the indoor combustion of coal emissions as Group 1, a known carcinogen to humans. Indoor air pollution exposure is greatest in individuals who live in rural developing countries. Interventions have been limited and show only mixed results. To reduce the morbidity and mortality from indoor air pollution, countermeasures have to be developed that are practical, efficient, sustainable, and economical with involvement from the government, the commercial sector, and individuals. This review focuses on the contribution of solid fuels to indoor air pollution.

Indoor air pollution in cities in China is mainly from domestic coal combustion, and from coal and biomass fuel combustion in rural areas. Factors affecting indoor air pollutant concentrat...

Background Unprocessed biomass fuel is the primary source of indoor air pollution (IAP) in developing countries. The use of biomass fuel has been linked with acute respiratory infections. This study assesses sources of variations associated with the level of indoor nitrogen dioxide (NO2). Materials and methods This study examines household factors affecting the level of indoor pollution by measuring NO2. Repeated measurements of NO2 were made using a passive diffusive sampler. A Saltzman colorimetric method using a spectrometer calibrated at 540 nm was employed to analyze the mass of NO2 on the collection filter that was then subjected to a mass transfer equation to calculate the level of NO2 for the 24 hours of sampling duration. Structured questionnaire was used to collect data on fuel use characteristics. Data entry and cleaning was done in EPI INFO version 6.04, while data was analyzed using SPSS version 15.0. Analysis of variance, multiple linear regression and linear mixed model were used to isolate determining factors contributing to the variation of NO2 concentration. Results A total of 17,215 air samples were fully analyzed during the study period. Wood and crop were principal source of household energy. Biomass fuel characteristics were strongly related to indoor NO2 concentration in one-way analysis of variance. There was variation in repeated measurements of indoor NO2 over time. In a linear mixed model regression analysis, highland setting, wet season, cooking, use of fire events at least twice a day, frequency of cooked food items, and interaction between ecology and season were predictors of indoor NO2 concentration. The volume of the housing unit and the presence of kitchen showed little relevance in the level of NO2 concentration. Conclusion Agro-ecology, season, purpose of fire events, frequency of fire activities, frequency of cooking and physical conditions of housing are predictors of NO2 concentration. Improved kitchen conditions and ventilation are highly recommended.

Indoor air pollution levels are reported to be higher with biomass fuel, and a number of respiratory diseases in children are associated with pollution from burning such fuel. However, little is known about the situation in developing countries. The aim of the study was to compare indoor air pollution levels and prevalence of symptoms in children between biomass- and fossil-fuel-using households in different seasons in Bangladesh. We conducted a cross-sectional study among biomass- (n = 42) and fossil-fuel (n = 66) users having children

Hazards in our indoor environments have been recognized since biblical times. The advice in Leviticus 14:33–48 for treating mold infested houses has contemporary meaning in the recent World Health Organization (WHO) document on damp and moldy indoor spaces [1]. In the developed world, faulty combustion, carbon monoxide from coal gas, lead paint, poor ventilation of tenement housing and hospitals have been recognized for decades as unhealthy. Indoor air quality, however, was not appreciated as an important component of public health until the proliferation of sealed buildings, energy conservation programs (urea formaldehyde foam insulation), new products, and the recognition of the health effects of radon, asbestos and latex. [...]

In Pakistan, almost 70% of the population lives in rural areas. Ninety-four percent of households in rural areas and 58% in urban areas depend on biomass fuels (wood, dung, and agricultural waste). These solid fuels have poor combustion efficiency. Due to incomplete combustion of the biomass fuels, the resulting smoke contains a range of health-deteriorating substances that, at varying concentrations, can pose a serious threat to human health. Indoor air pollution accounts for 28,000 deaths a year and 40 million cases of acute respiratory illness. It places a significant economic burden on Pakistan with an annual cost of 1% of GDP. Despite the mounting evidence of an association between indoor air pollution and ill health, policy makers have paid little attention to it. This review analyzes the existing information on levels of indoor air pollution in Pakistan and suggests suitable intervention methods. This review is focused on studies of indoor air pollution, due to biomass fuels, in Pakistan published in both scientific journals and by the Government and international organizations. In addition, the importance of environmental tobacco smoke as an indoor pollutant is highlighted. Unlike many other developing countries, there are no long-term studies on the levels of indoor air pollution. The limited studies that have been undertaken indicate that indoor air pollution should be a public health concern. High levels of particulate matter and carbon monoxide have been reported, and generally, women and children are subject to the maximum exposure. There have been a few interventions, with improved stoves, in some areas since 1990. However, the effectiveness of these interventions has not been fully evaluated. Indoor air pollution has a significant impact on the health of the population in Pakistan. The use of biomass fuel as an energy source is the biggest contributor to poor indoor air quality followed by smoking. In order to arrest the increasing levels of indoor pollution, there is a dire need to recognize it as a major health hazard and formulate a national policy to combat it. An integrated effort, with involvement of all stakeholders, could yield promising results. A countrywide public awareness campaign, on the association of indoor air pollution with ill health, followed by practical intervention would be an appropriate approach. Due to the current socioeconomic conditions in the country, development and adoption of improved cooking stoves for the population at large would be the most suitable choice. However, the potential of biogas as a fuel should be explored further, and modern fuels (natural gas and LPG) need to be accessible and economical. Smoking in closed public spaces should be banned, and knowledge of the effect of smoking on indoor air quality needs to be quantified.

The World Health Organization's 2004 Global and Regional Burden of Disease Report estimates that acute respiratory infections from indoor air pollution (pollution from burning wood, animal dung, and other bio-fuels) kill a million children annually in developing countries, inflicting a particularly heavy toll on poor families in South Asia and Africa. This paper reports on an experiment that studied the use of different fuels in conjunction with different combinations of construction materials, space configurations, cooking locations, and household ventilation practices (use of doors and windows) as potentially-important determinants of indoor air pollution. Results from controlled experiments in Bangladesh were analyzed to test whether changes in these determinants can have significant effects on indoor air pollution. Analysis of the data shows, for example, that pollution from the cooking area is transported into living spaces rapidly and completely. Furthermore, it is important to factor in the interaction between outdoor and indoor air pollution. Hence, the optimal cooking location should take 'seasonality' in account. Among fuels, seasonal conditions seem to affect the relative severity of pollution from wood, dung, and other biomass fuels. However, there is no ambiguity about their collective impact. All are far dirtier than clean (LPG and Kerosene) fuels. The analysis concludes that if cooking with clean fuels is not possible, then building the kitchen with permeable construction material and providing proper ventilation in cooking areas will yield a better indoor health environment. PRACTICAL IMPLICATIONS: Several village-level measures could significantly reduce IAP exposure in Bangladesh. All would require arrangements and the assert of male heads-of-household: negotiated bulk purchases of higher cost, cleaner fuels; purchase of more fuel-efficient stoves; peripheral location of cooking facilities; building the kitchen with permeable construction material; rotation of women in cooking roles, to reduce their exposure; and ventilation of smoke through a stack tall enough to disperse smoke over a relatively broad area. It is expected that village men and women will agree to these measures if they become convinced that IAP poses a serious risk to health, and their actions will significantly reduce the risk. The keys to success are effective public education about the sources and risks of IAP, and financial and technical assistance for changes in cooking arrangements.

Indoor air pollution due to the indoor burning of polluting fuels has been associated with Acute Lower Respiratory Infections (ALRI) amongst children less than five years old. This paper reviews evidence of the association between household energy, indoor air pollution and child ALRI in South Africa. Studies show evidence consistent with the international literature with the likelihood of ALRI between 2 and 4 amongst children living in households using polluting fuels compared to households using electricity. Indoor air pollution is responsible for the deaths of up to 1 400 children annually. Interven-tions have demonstrated 46 – 97% lower pollution concentrations compared to open fires. However, the sustainability of selected interventions has been questioned in certain contexts. The paper discusses the strengths and weaknesses of the evidence and highlights opportunities for further research.

Until the middle of this century, air pollution was primarily a problem of urban and industrial regions. In the last three decades, changes in the dispersal of pollutants and increases in motor vehicle emissions have led to greater pollutant impacts in more remote rural areas. On a national scale in North America and western Europe, current losses of agricultural production due to air pollutants are small relative to other factors, but local impacts on sensitive crops may be substantial. Current international trends suggest that now, and in the future, the greatest concern should be over impacts on agriculture in newly industrialized and developing countries, rather than in those countries where most research effort is currently concentrated.

UNLABELLED In developing countries biomass combustion is a frequently used source of domestic energy and may cause indoor air pollution. Carbon monoxide (CO)and particulate matter with an aerodynamic diameter of 2.5 lm or less (PM2.5)were measured in kitchens using wood or natural gas (NG) in a semi-rural community in Pakistan. Daytime CO and PM2.5 levels were measured for eight continuous hours in 51 wood and 44 NG users from December 2005 to April 2006. The laser photometer PM2.5 (Dustrak, TSI) was calibrated for field conditions and PM2.5 measurements were reduced by a factor of 2.77. CO was measured by an electrochemical monitor (Model T15v, Langan). The arithmetic mean for daytime CO concentration was 29.4 ppm in wood users; significantly higher than 7.5 ppm in NG users (P < 0.001). The arithmetic mean for daytime PM2.5 concentrations was 2.74 mg/m3 in wood users; significantly higher than 0.38 mg/m3 in NG users (P < 0.001). Higher peak levels of CO and PM2.5 were also observed in wood users. Time spent in the kitchen during fuel burning was significantly related to increasing CO and PM2.5 concentrations in wood users.These findings suggest that cooking with wood fuel may lead to hazardous concentrations of CO and PM2.5. PRACTICAL IMPLICATIONS Biomass combustion is frequently used in developing countries for cooking. This study showed very high level of air pollution in kitchens using wood as the cooking fuel. Many people, especially women and children, are vulnerable to exposure to very high levels of air pollutants as they spend time in the kitchen during cooking hours.

Some cities face severe air pollution problems, while other cities of similar population sizes are much cleaner. For example, World Bank data from 1995 indicates that for a sample of major cities where air quality was monitored, the ambient particulate level of the average Asian city was four times higher than that of the average city in Western Europe. In the year 1995, there were at least 25 cities in Asia whose ambient particulate levels exceeded three times the World Health Organization’s annual particulate standard of 90 μg m (micrograms per cubic meter). Urban air pollution can significantly degrade quality of life. In polluted cities, time spent outside is dangerous to one’s health. Such cities may have trouble attracting footloose high tech firms and their amenity-seeking workers to locate there. A mayor of such a city might wonder: How did this city become so polluted? What cost-effective regulations could be enacted to clean up the city? How much would people be willing to pay to reduce local pollution? This chapter seeks to examine each of these issues by focusing on the supply and demand for urban air pollution. There are numerous examples of polluted cities, such as Los Angeles, Krakow, and Pittsburgh, that have made dramatic pollution progress. There are other cities whose pollution levels are increasing or are only slowly improving. This diversity of experiences means that researchers can test hypotheses concerning what drives urban air pollution and can investigate what policies effectively mitigate urban air pollution. A challenge in making progress in understanding the causes and consequences of urban air pollution is that it really requires an interdisciplinary research team. Public health experts focus on measuring the health impacts of air pollution exposure. Atmospheric chemists examine how ambient air pollution is affected by urban emissions increases. Engineers focus on what are the set of feasible technologies that can be used to mitigate a pollution problem. Economists bring

Summary One-third of the world's population burn organic material such as wood, dung or charcoal (biomass fuel) for cooking, heating and lighting. This form of energy usage is associated with high levels of indoor air pollution and an increase in the incidence of respiratory infections, including pneumonia, tuberculosis and chronic obstructive pulmonary disease, low birthweight, cataracts, cardiovascular events and all-cause mortality both in adults and children. The mechanisms behind these associations are not fully understood. This review summarises the available information on biomass fuel use and health, highlighting the current gaps in knowledge.

The United Nations Commission for Sustainable Development may not appear, at first sight, to be a major playing field for public health. Nevertheless, when environment, energy and development ministers from around the world assembled in New York on 1-12 May 2006 for the Commission's 14th session, health concerns in relation to energy production and consumption emerged as a prominent argument in discussions on energy for sustainable development. In his opening speech, Secretary General Kofi Annan called attention to the fact that indoor air pollution from solid fuel use is one of the world's ten major causes of mortality and morbidity. (1) More than half the world's population--3.2 billion people--still burn coal and biomass fuels such as wood, dung and crop residues to meet their basic energy needs. (2) Indoor air pollution from burning these solid fuels on open fires or traditional stoves comprises a variety of health-damaging pollutants including particles, carbon monoxide and different carcinogens (3) and is the cause of a public health tragedy. Every year, 1.5 million people die from inhaling indoor pollutants that often exceed accepted guideline limits for outdoor air: in the case of fine particles, the limit is exceeded by 100 times or more. (4, 5) Children and women are disproportionately affected, with nearly 800 000 deaths attributable to indoor air pollution occurring among children under five years of age and more than 500 000 such deaths occurring among women. (5) Preventing deaths caused by polluted indoor air must no longer be delayed. In the short term, stoves that burn more cleanly and use fuel more efficiently, ventilation that is improved through smoke hoods or enlarged spaces in the eaves, and changes in housing design can substantially reduce pollutant levels. In the longer term, the use of cleaner fuels, such as liquefied petroleum gas, biogas or other modern biofuels, can eliminate the current indoor air pollution epidemic. Improving access to modern energy services--including electricity and modern cooking fuels and appliances--is essential if the world is to achieve its Millennium Development Goals (MDGs). The United Nations Millennium Project recommends an additional MDG target "to halve, by 2015, the number of people without effective access to modern cooking fuels, and to make improved cooking stoves widely available". (6) The challenge in working towards this target is enormous: every day for the next 10 years, 485 000 people will need to gain access to cleaner fuels or improved stoves. Even if the target is realized, 1.5 billion people will still be left on the sidelines of development in 2015. (5) "Effective solutions exist and the economic case for taking practical solutions to scale is just as strong as the humanitarian case", emphasized the late Dr LEE Jong-wook, Director-General of WHO. …

Indoor air pollution is ubiquitous, and takes many forms, ranging from smoke emitted from solid fuel combustion, especially in households in developing countries, to complex mixtures of volatile and semi-volatile organic compounds present in modern buildings. This paper reviews sources of, and health risks associated with, various indoor chemical pollutants, from a historical and global perspective. Health effects are presented for individual compounds or pollutant mixtures based on real-world exposure situations. Health risks from indoor air pollution are likely to be greatest in cities in developing countries, especially where risks associated with solid fuel combustion coincide with risk associated with modern buildings. Everyday exposure to multiple chemicals, most of which are present indoors, may contribute to increasing prevalence of asthma, autism, childhood cancer, medically unexplained symptoms, and perhaps other illnesses. Given that tobacco consumption and synthetic chemical usage will not be declining at least in the near future, concerns about indoor air pollution may be expected to remain.

Agricultural practice in both the developed and developing world has always aimed to eliminate or minimize the numerous constraints on producing maximum yield of crops. These constraints may be abiotic, including nutrient deficiency, metal toxicity, salinity, drought, low and high temperatures, wind, and waterlogging. There are also numerous biotic constraints: invertebrate and vertebrate pests; fungal, viral, and bacterial pathogens;and trampling. Although vast sums of money are spent on overcoming these, there is another constraint that receives much less attention, but with evidence that it is potentially a widespread threat to crop production: air pollution. As early as the 17th century, the noted English diarist John Evelyn (1661) described graphically the effects of the smoke ridden air of London on ornamental plants and fruit trees growing in the city. Research into this phenomenon that commenced in the late 19th century was initially concerned with trees near smelters in both Europe and North America.In the final three decades of the last century, this research mushroomed, with extensive programs in many parts of the developed world. Much of this research was aimed at understanding the effects on crop yield and growth of the ubiquitous primary pollutants, sulphur dioxide (S02), and nitrogen oxides (NOX), as well as the secondary pollutant ozone (03), indicating that all three pollutants were at different times and in different places having serious deleterious effects on crop productivity, with the two primary pollutants being associated mainly with industrial point sources and the urban fringe, whereas 03 was widespread at phytotoxic levels in rural areas. Subsequently interest also developed into the potential for air pollution to have indirect adverse effects on crops by exacerbating the impacts of familiar biotic stresses, such as pets and pathogens, and abiotic stresses, such as drought and frost.

BACKGROUND A critical review was conducted of the quantitative literature linking indoor air pollution from household use of biomass fuels with acute respiratory infections in young children, which is focused on, but not confined to, acute lower respiratory infection and pneumonia in children under two years in less developed countries. Biomass in the form of wood, crop residues, and animal dung is used in more than two fifths of the world9s households as the principal fuel. METHODS Medline and other electronic databases were used, but it was also necessary to secure literature from colleagues in less developed countries where not all publications are yet internationally indexed. RESULTS The studies of indoor air pollution from household biomass fuels are reasonably consistent and, as a group, show a strong significant increase in risk for exposed young children compared with those living in households using cleaner fuels or being otherwise less exposed. Not all studies were able to adjust for confounders, but most of those that did so found that strong and significant risks remained. CONCLUSIONS It seems that the relative risks are likely to be significant for the exposures considered here. Since acute lower respiratory infection is the chief cause of death in children in less developed countries, and exacts a larger burden of disease than any other disease category for the world population, even small additional risks due to such a ubiquitous exposure as air pollution have important public health implications. In the case of indoor air pollution in households using biomass fuels, the risks also seem to be fairly strong, presumably because of the high daily concentrations of pollutants found in such settings and the large amount of time young children spend with their mothers doing household cooking. Given the large vulnerable populations at risk, there is an urgent need to conduct randomised trials to increase confidence in the cause-effect relationship, to quantify the risk more precisely, to determine the degree of reduction in exposure required to significantly improve health, and to establish the effectiveness of interventions.