Health

Table of Contents
1. The issue in brief 2. Major Air pollutants Released From Biomass Combustion 3. Health impacts of indoor air pollution 4. Specific Diseases Associated With Indoor Air Pollutant Exposure 5. Intervention 6. Current Best Practice 7.Areas of Research 8.Weblinks 9. Resources on HEDON 10. Organizations and People Sources

[top] [end]1. The issue in brief

[top] [end]Introduction

Household cooking in developing countries can have a number of serious health impacts including burns and indoor air pollution (discussed below).

[top] [end]Indoor Air Pollution

In many people's minds air pollution is associated with the contamination of urban air from automobile exhausts and industrial effluents.

Indoor air gets polluted in the presence of excessive levels of air contaminants inside a home or building from sources such as cigarette smoking, fuel combustion for heating or cooking, certain wallboards, carpets, or insulation as well as the geology of the area (radon in soil or rocks beneath the structure). Emissions are more likely to accumulate in structures having limited air exchange with the outside. Many air pollutants typically have higher concentrations indoors than outdoors.

However, in developing countries, the problem of indoor air pollution far outweighs the ambient air pollution. There are four principal sources of pollutants of indoor air (i) combustion, (ii) building material, (iii) the ground under the building, and (iv) bioaerosols

In developed countries the most important indoor air pollutants are radon, asbestos, volatile organic compounds, pesticides, heavy metals, animal dander, mites, moulds and environmental tobacco smoke. However, in developing countries the most important indoor air pollutants are the combustion products of unprocessed solid biomass fuels used by the poor urban and rural folk for cooking and heating.

A recent report of the World Health Organization asserts the rule of 1000 which states that a pollutant released indoors is one thousand times more likely to reach people's lung than a pollutant released outdoors.

Almost half the world's population, around 3000 million people, still rely on biomass fuel - i.e. wood, animal dung or crop wastes - and coal, for their everyday household energy needs (World Resources Institute 1998). Although accurate data are scarce, estimates suggest that wood provides around 15% of the energy needs in developing countries, and as much as 75% in tropical Africa. In more than 30 countries, wood provides more than 70% of the energy needs, and in 13 countries it is over 90% (World Energy Council 1999). Over the last 25 years, the trend in global biofuel use has changed little, and in some parts of the world where poverty and the prices of alternative fuels such as kerosene and bottled gas have increased, the use of biomass has increased (WHO 1997).

In almost all the South Asian countries, women generally cook under poorly ventilated conditions using biomass fuels, such as wood, crop residues or dung cakes, either in pits or in open U-shaped stoves, called chulhas.It is estimated that about half a million women and children die every year from indoor air pollution in India (Smith 2000a). Compared to other countries, India has among the largest burden of disease due to the use of unclean household fuels, and 28% of all deaths due to indoor air pollution in developing countries occur in India (Smith 2000a). According to the Census of India 2001, more than 72% of households still use unprocessed biomass as cooking fuel. In rural areas this is around 90% (Office of the Registrar General India 2003).

With development, there is generally a transition up the so-called 'energy-ladder' to fuels which are progressively more efficient, cleaner, convenient and expensive. The type of fuels used by a household is determined mainly by its economic status. In the energy ladder, biomass fuels namely animal dung, crop residues and wood, which are the dirtiest fuels, lie at the bottom and are used mostly by very poor people. Electricity, which is the most expensive, lies at the top of ladder and it is also the cleanest fuel. The 1991 National Census (India) for the first time inquired about the fuel used for cooking. It revealed that about 90% of the rural population relied upon the biomass fuels like animal dung, crop residues and wood. A small portion used coal. Nation-wide about 78% of the population relied upon the biomass fuels and 3% on coal.

It is important to emphasize that households typically use a combination of fuels - for example, wood for cooking and heating, kerosene for lighting, and perhaps charcoal for space heating etc. Thus, there is not a simple linear progression up this ladder, but it is nevertheless the case that households will tend to carry out more tasks with more modern fuels as their socio-economic circumstances improve. However, the problem remains that almost half of the world's population relies predominantly on fuels like firewood, dung, and crop residues using simple stoves and open fires, often without chimneys, flues or appropriate ventilation devices and for many, the prospects of moving up the ladder in the short term appear limited. So the relationship between meager income and the reliance on biomass energy makes the urban and rural poor carry a disproportionately large share of heavy household indoor pollution worldwide.

[top] [end]2. Major Air pollutants Released From Biomass Combustion

It has been estimated that more than half world's households cook their food on the unprocessed solid fuels that typically release at least 50 times more noxious pollutants than gas . The stoves or chullah used for cooking are not energy efficient. The fuels re not burned completely. The incomplete combustion of biomass releases complex mixture of organic compounds, which include suspended particulate matter, carbon monoxide (CO), poly organic material (POM), poly aromatic hydrocarbons (PAH), formaldehyde, etc. The biomass may also contain intrinsic contaminants such as sulphur, trace metals, etc.

[top] [end]Particulates

In recent years a large number of studies of health impact of suspended particulate air pollution have been undertaken in developing countries. These studies show remarkable consistency in the relationship observed between changes in daily ambient suspended particulate levels and changes in mortality. Smith estimated the health risk from exposure to particulate air pollution by applying the mean risk per unit ambient concentrations based on the results of some urban epidemiological studies. The range of risk was found to be 1.2 - 4.4% increased mortality per 10 mg/m3 incremental increase in concentration of respirable suspended particles (PM10). For the calculations of estimates, it was assumed that the health risk has linear relationship to exposure, the risk factors determined for urban centers of developed nations were used as standards; where the PM10 data were not available, 50% of suspended particulate matter (SPM) levels were considered as equivalent. The above assumptions may add to inaccuracy already inherent in such estimates.

Studies from a number of countries in Asia, Africa and the Americas have measured the levels of indoor air pollution associated with cooking on biomass fuels (Smith 1987, Bruce et al. 2000). Most of these studies have measured particles - complex mixtures of chemicals in solid form and droplets. These particles are thought to be the most health-damaging component of smoke pollution, especially the smaller ones which are able to penetrate deep into the lungs.

Particles are usually described by size or their effective (aerodynamic) diameter, which is measured in microns (millionths of a metre). Concentrations of particles are expressed as the weight of particles (in micrograms, mg) per cubic metre (m3) of air, thus mg/m3. Particles of up to 10 microns in diameter (PM10) have been most commonly measured, although some have looked at the total (i.e. all) suspended particles (TSP), which tends to include dust from sources other than combustion. Recent evidences reveal that the very smallest particles are the most dangerous and some studies have measured particles up to 2.5 microns in diameter (PM2.5).

For consistency, only results for PM10 will be discussed here. Typical 24-hour mean levels of PM10 in homes using biofuels range from 300 to >3000 mg/m3, and during use of an open fire, the PM10 level can reach 20 000 mg/m3 or more. By comparison, the US-EPA standard for daily (24-hour) average PM10 is 150 mg/m3 (this concentration should be exceeded only in one per 100 days), while the annual average should not exceed 50 mg/m3 (USEPA 1997). Most 'western' cities rarely exceed these standards, whereas in rural homes in developing countries, they are exceeded on a daily basis by a factor of 10, 20, and sometimes more. Levels of carbon monoxide and other pollutants also often exceed the standard guidelines.

[top] [end]Carbon Monoxide

Incomplete combustion of fuels produces carbon monoxide, (CO). The CO and particle emission pose a serious problem when biomass fuels are used. Smith has estimated that about 38, 17, 5 and 2 g/meal carbon monoxide is released during the household cooking, using dung, crop residues,wood and kerosene respectively. During the use of liquid petroleum gas a negligible amount of CO is released. A study by the National Institute of Occupational Health (NIOH), Ahmedabad reported indoor air CO levels of 144, 156, 94, 108 and 14 mg/m3 air during cooking by dung, wood, coal, kerosene and LPG respectively. The short-term health effects of CO exposure are dizziness, headache, nausea, feeling of weakness, etc. The association between long-term exposure to carbon monoxide from cigarette smoke and heart disease and foetal development has been described by several authors.

[top] [end]Poly Organic Material and Poly Aromatic Hydrocarbons

Poly organic material is a loose term used to depict a group of chemicals having two or more rings. Of several chemicals included in this group, the PAHs have attracted interest for their possible carcinogenic effects. In addition to PAH, azo and arino compounds have also been found to be potentially carcinogenic. Most other categories of POM are of less environmental interest or are not found in large amounts in organic combustion products. Polycyclic aromatic hydrocarbons constitute a large class of compounds released during the incomplete combustion or pyrolysis of organic matter. They are often called polynuclear aromatic (PNA) because they contain three or more aromatic rings that share carbon atoms. Benzo(a)pyrene (BaP) is one of the most important carcinogen of the group. Often it is measured to indicate the presence or absence of PAHs although the relationship. between BaP content and actual carcinogenicity may be weak. Anthracene and phenanthracene are not carcinogens but methyl additions may render them carcinogenic. PAHs are activated by the hepatic microsomal enzyme system to carcinogenic forms that bind covalently to DNA. Study by NIOH19 showed that the indoor levels of PAH (total) during use of dung, wood, coal, kerosene and LPG were 3.56, 2.01, 0.55, 0.23 and 0.13 µg/m3 of air respectively. These PAH were fluorene, pyrene,chrysene,benzo(a)anthracene, benzo(b)fluoranthene, benzo(k)fluoranthene,benzo(a)pyrene,dibenz(ah)anthracene, benzo(ghi)perylene and indeno(1,2,3-cd) pyrene. All these PAHs except the first three have been classified as possible carcinogens.

[top] [end]Formaldehyde

A study was done to measure levels of formaldehyde in indoor environment during cooking by different fuels. The formaldehyde mean levels were 670, 652, 109, 112 and 68 µg/m3 of air for cattle dung, wood, coal, kerosene and LPG respectively. The formaldehyde is well recognized to be an acute irritant and long-term exposure can cause a reduction in vital capacity and chronic bronchitis. The formaldehyde is well known to form crosslinks with biologic macro-molecules. Inhaled formaldehyde forms DNA and DNA-protein cross-links in the nasal respiratory mucosa. The formaldehyde has been shown to be carcinogenic in a dose dependent fashion in rodents. The studies done in workers occupationally exposed to formaldehyde have consistently (11 of 13studies reviewed) shown higher incidence of leukaemia23. In an epidemiological study in U.K., significantly excess mortality from lung cancer was observed in workers exposed to high levels of formaldehyde.

[top] [end]Mutagenic Activity of the Smoke Particulate Extract

Microbial tests are widely used as a screening tool for assessing mutagenic potential of chemical substances. The particulate matter in the smoke generated as a result of incomplete combustion of biomass fuels contains a number of organic compounds. To evaluate their carcinogenic potential, it is necessary to screen their mutagenicity through simple and rapid microbial assay as a first step. Ames assay is simple and sensitive enough to measure mutagenicity of air-borne particulates, so that many researchers have applied this assay to demonstrate the ambient carcinogenic and mutagenic compounds in the extractable organic matter from air-borne particulates. Mutagenic response of complex mixtures of polycyclic organic matter from the combustion of biomass energy fuels was studied using tester strains TA 98 and TA 100 of Salmonella typhimurium which can detect the presence of frame-shift and base-pair mutagens. The results indicated that the organic residues of smoke particulates of wood and cattle dung fuels contained direct acting frameshift mutagens and cattle dung contained only direct acting base-pair mutagens while indirect acting frame-shift and base-pair mutagens were found to present in smoke particulates of both the energy fuels.

The traditional stoves burn biomass inefficiently and release high volumes of noxious air pollutants. Also, fires from biomass fuels require continuous feeding of biomass to the stove, which results in extended exposure to the pollutants. . This exposure causes half a million premature deaths every year. According to the World Health Organization, indoor air pollution due to biomass smoke is one of the largest environmental risk factors for ill-health of any kind. Exposure to contaminated indoor air has been identified as a significant cause of health problems affecting the poor in developing countries, especially women and younger children.

[top] [end]3. Health impacts of indoor air pollution

Health is influenced by a wide range of physical, social and environmental factors. In addition to the production of toxic pollution, the supply and use of household energy in conditions of poverty and scarcity affects health - particularly of women and young children - in a variety of ways that encompass physical injury, lost opportunity for income generation, environmental stress, and many other issues.

Indoor air pollution is the clearest and most direct physical health risk, and there is now fairly consistent evidence that biomass smoke exposure increases the risk of a range of common and serious diseases of both children and adults (Bruce et al. 2000). Chief among these is childhood acute lower respiratory infections (ALRI), particularly pneumonia (Smith et al. 2000). Association of exposure with chronic bronchitis (long-term cough and phlegm) and chronic obstructive lung disease (narrowing of airways in the lung, which is progressive and can be only partially reversed) is quite well established, particularly among women. There is also evidence, mainly from China, that exposure to coal smoke in the home markedly increases the risk of lung cancer, particularly in women.

In recent years, new evidence has emerged which suggests that indoor air pollution (IAP) in developing countries may also increase the risk of other important child and adult health problems, such as low birth weight, perinatal mortality (stillbirths and deaths in the first week of life), asthma, and middle ear infection in children, tuberculosis, nasopharyngeal and laryngeal cancer, and cataract in adults (Bruce et al. 2000).

Drawing on the most consistent studies of ALRI, COPD and lung cancer, the World Health Organisation has recently estimated that IAP is responsible for around 2 million deaths per year, and 2.7% of the global burden of disease, expressed as Disability Adjusted Life Years lost [WHO 2002]. This placed IAP eighth in the global ranking of key risk factors for disease.

A more information picture can be gained from a focus on the poorest countries - those with the highest levels of mortality and the greatest dependence on solid fuel. Among these countries, the use of solid fuels was ranked fourth among key risk factors for health, behind malnutrition, unsafe sex (AIDS/HIV) and water/sanitation , responsible for around 1 million deaths and 4% of DALYs. The majority of these DALYs arise from ALRI in young children, and it is estimated that approximately 40% of all child deaths from this condition in the high mortality developing countries are the result of exposure to indoor air pollution.

[top] [end]4. Specific Diseases Associated With Indoor Air Pollutant Exposure

Respiratory illness, cancer, tuberculosis, perinatal outcomes including low birth weight, and eye diseases are the morbidities associated with indoor air pollution.

[top] [end]Respiratory Illness

The effect of air pollutants in general would depend on the composition of the air that is inhaled which will depend on the type of fuel used and the conditions of combustion, ventilation and duration for which the inhalation occur. The most commonly reported and obvious health effect of indoor air pollutants is the increase in the incidence of respiratory morbidity. Studies by the NIOH on the prevalence of respiratory symptoms in women using traditional fuels (biomass) (n=175) and LPG (n=99), matched for economic status and age, indicated that the relative risk (with 95% C.I.) for cough, and shortness of breath (dyspnoea) was 3.2 (1.6-6.7), and 4.6 (1.2-18.2) respectively.

[top] [end]Childhood acute respiratory infections

Acute lower respiratory infections Acute respiratory infections (ARIs) are the single most important cause of mortality in children aged less than 5 years, accounting for around 3-5 million deaths annually in this age group. Many studies in developing countries have reported on the association between exposure to indoor air pollution and acute lower respiratory infections. The studies on indoor air pollution from household biomass fuel are reasonably consistent and, as a group, show a significant increase in risk for exposed young children compared with those living in households using cleaner fuels or being otherwise less exposed. Some of the studies carried out in India have reported no association between use of biomass fuels and ARI in children. In a case-control study in children under five years of age in south Kerala, where children with severe pneumonia as ascertained by WHO criteria were compared with those having nonsevere ARI attending out patient department, the fuel used for cooking was not a significant risk factor for severe ARI. Non-severe ARI controls may represent the continuum (predecessor) of the cases themselves. Sharma et al in a cross-sectional study in 642 infants dwelling in urban slums of Delhi and using wood and kerosene respectively, did not find a significant difference in the prevalence of acute lower respiratory tract infections and the fuel type.

[top] [end]Upper respiratory tract infections and otitis media

Studies on the relationship between indoor air pollution and acute upper respiratory infections in children both from developed and developing nations have not been able to demonstrate the relationship between the two. However, there is strong evidence that exposure to environmental tobacco smoke causes middle ear disease. A recent meta-analysis reported an odds ratio of 1.48 (1.08-2.04) for recurrent otitis media if either parent smoked, and one of 1.38 (1.23-1.55) for middle ear effusion in the same circumstances. A clinic based case-control study of children in rural New York state reported an adjusted odds ratio for otitis media, involving two or more separate episodes, of 1.73 (1.03-2.89) for exposure to woodburning stoves.

[top] [end]Chronic pulmonary diseases

[top] [end]Chronic obstructive pulmonary disease and chronic cor Pulmonale

In developed countries, smoking is responsible for over 80% of cases of chronic bronchitis and for most cases of emphysema and chronic obstructive pulmonary disease. Padmavati and colleagues pointed out to the relationship between exposure to indoor air pollutants and chronic obstructive lung disease leading to chronic cor pulmonale. These studies showed that in India, the incidence of chronic cor pulmonale is similar in men and women despite the fact that 75% of the men and only 10% women are smokers. Further analysis of the cases of chronic cor pulmonale in men and women showed that chronic cor pulmonale was more common in younger women. Chronic cor pulmonale seemed to occur 10-15 years earlier in women. The prevalence of chronic cor pulmonale was lower in the southern states than the northern states of India. This is attributed to higher ambient temperatures during most part of the year allowing for greater ventilation in the houses during cooking. The authors attributed this higher prevalence of chronic cor pulmonale in women to domestic air pollution as a result of the burning of solid biomass fuels leading to chronic bronchitis and emphysema which result in chronic cor pulmonale. Subsequent studies in India confirmed these findings. Numerous studies from other countries, including ones with cross-sectional and case-control designs, have reported on the association between exposure to biomass smoke and chronic bronchitis or chronic obstructive pulmonary disease. An ongoing series of studies at four locations in India, funded by Fogarty International, is addressing the question of whether exposure to indoor smoke from solid fuels aggravates tuberculosis. It is expected to complete collecting data by the end of next year.

[top] [end]Pneumoconiosis

Pneumoconiosis is a disease of industrial workers occupationally exposed to fine mineral dust particles over a long time. The disease is most frequently seen in miners. Cases of respiratory morbidity who did not respond to routine treatment and whose radiological picture resembled pneumoconiosis have been reported in Ladakh. However, there are no industries or mines in any part of Ladakh and therefore exposure to dust from these sources was ruled out. Two factors considered responsible for the development of this respiratory morbidity were (i) Exposure to dust from dust storms. In the spring dust storms occur in many parts of Ladakh. During these storms the affected villages are covered by a thick blanket of fine dust, and the inhabitants are exposed to a considerable amount of dust for several days. The frequency, duration and severity of these dust storms vary considerably from village to village; (ii) Exposure to soot - due to the severe cold in Ladakh, ventilation in the houses is kept at a minimum. The fire place is used for both cooking and heating purposes. To conserve fuel during non-cooking periods, the wood is not allowed to burn quickly but is kept smouldering to prolong its slow heating effect. The inmates are thus exposed to high concentrations of soot. The clinico-radiological investigations of 449 randomly selected villagers from three villages having mild, moderate and severe dust storms showed prevalence of pneumoconiosis of 2.0, 20.1 and 45.3% respectively. The chest radiographs of the villagers showed radiological characteristics which were indistinguishable from those found in miners and industrial workers suffering from pneumoconiosis. The dust concentrations in the kitchens without chimneys varied from 3.22 to 11.30 mg/m3 with a mean of 7.50 mg/m3. The free silica content of these dust samples was below 1%. Dust samples sufficient to allow measurement of the dust concentrations could not be collected during the periods of dust storms. A preliminary analysis of the settled dust samples collected immediately after the storms indicated that about 80% of the dust was respirable and the free silica content ranged between 60 and 70%. Detailed statistical analysis of the data showed that the frequency of dust storms, use of chimney in the houses and age were the most important factors related to the development of pneumoconiosis. Thus, the results of medical and radiological investigations positively established the occurrence of pneumoconiosis in epidemic proportion. Exposure to free silica from dust storms and soot from domestic fuel were suggested as the causes of pneumoconiosis. Low oxygen levels or some other factor associated with high altitude may be an important contributory factor in causation of pneumoconiosis because it has been reported that the miners working at high altitude are more prone to develop pneumoconiosis than their counterparts exposed to the same levels of dust and working in the mines at normal altitude.

[top] [end]Lung Cancer

The link between lung cancer in Chinese women and cooking on an open coal stove has been well established. Smoking is a major risk factor for lung cancer, however, about two-thirds of the lung cancers were reported in nonsmoking women in China, India and Mexico. The presence of previous lung disease, for example tuberculosis which is common in Indian women, is a risk factor for development of lung cancer in non-smokers. The smoke from biomass fuels contain a large number of compounds such as poly aromatic hydrocarbons, formaldehyde, etc. known for their mutagenic and carcinogenic activities, but there is a general lack of epidemiological evidence connecting lung cancer with biomass fuel exposure. The factors associated with rural environment may have a modulating effect on the occurrence of lung cancer and therefore the low incidence of lung cancer in Indian women should not lead to a final conclusion of no link between biomass exposure and lung cancer. It may be concluded that at present there is limited evidence of indoor exposure from coal fires leading to lung cancer and there is no evidence for the biomass fuels. Further investigations are needed to reach definite conclusions.

[top] [end]Pulmonary Tuberculosis

Mishra et al recently reported the association between use of biomass fuels and pulmonary tuberculosis on the basis of analysis of data collected on 260,000 Indian adults interviewed during the 1992-93 National Family Health Survey. Persons living in households burning biomass fuels were reported to have odd ratio of 2.58 (1.98-3.37) compared to the persons using cleaner fuel, with an adjustment for confounding factors such as separate kitchen, indoor overcrowding, age, gender, urban or rural residence and caste. The analysis further indicated that, among persons aged 20 years and above, 51% of the prevalence of active tuberculosis was attributed to smoke from cooking fuel. However, this study has inherent weakness that the cases of tuberculosis were self reported. There is strong possibility of false reporting as no investigation was done to confirm the reliability of the reporting. Gupta and Mathur67 have reported similar findings from northern India. This study did not control for the confounding factors except for age. There is experimental evidence to show that the exposure to wood smoke may increases susceptibility of the lungs to infections. Exposure to smoke interferes with the mucociliary defences of the lungs and decreases several antibacterial properties of lung macrophages, such as adherence to glass, phagocytic rate and the number of bacteria phagocytosed. Chronic exposure to tobacco smoke also decreases cellular immunity, antibody production and local bronchial immunity, and there is increased susceptibility to infection and cancer. Indeed, tobacco smoke has been associated with tuberculosis. Although the evidence in favour of tuberculosis associated with biomass fuel exposure is extremely weak, there is a theoretical possibility of such an association and considering the public health importance of the problem further experimental and epidemiological studies are necessary.

[top] [end]Cataract

During cooking particularly with biomass fuels, air has to be blown into the fire from time to time especially when the fuel is moist and the fire is smouldering. This causes considerable exposure of the eyes to the emanating smoke. In a hospital-based case-control study in Delhi the use of liquefied petroleum gas was associated with an adjusted odds ratio of 0.62 (0.4-0.98) for cortical, nuclear and mixed, but not posterior sub capsular cataracts in comparison with the use of cow dung and wood. An analysis of over 170,000 people in India75 yielded an adjusted odds ratio for reported partial or complete blindness of 1.32 (1.16-1.50) in respect of persons mainly using biomass fuel compared with other fuels after adjusting for socio-economic, housing and geographical variables; there was a lack of information on smoking, nutritional state, and other factors that might have influenced the prevalence of cataract. It is believed that the toxins from biomass fuel smoke are absorbed systematically and accumulate in the lens resulting in its opacity. The growing evidence that environmental tobacco smoke causes cataracts is supportive.

[top] [end]Adverse Pregnancy Outcome

Low birth weight (LBW) is an important public health problem in developing nations attributed mainly to undernutrition in pregnant women. Low birth weight has serious consequences including increased possibility of death during infancy. Exposure to carbon monoxide from tobacco smoke during pregnancy has been associated with LBW. Levels of carbon monoxide in the houses using biomass fuels are high enough to result in carboxyhaemoglobin levels comparable to those in smokers. In rural Guatemala, babies born to women using wood fuel were 63 g lighter than those born to women using gas and electricity, after adjustment for socio-economic and maternal factors. A study carried out in Ahmedabad reported an excess risk of 50% of stillbirth among women using biomass fuels during pregnancy. An association between exposure to ambient air pollution and adverse pregnancy outcome has been widely reported.

Considering the association of LBW with a number of disease conditions later in life, there is a need for further studies.

[top] [end]5. Intervention

Women and young girls coughing and choking as they cook food over traditional stoves that burn wood, leaves or dung is a common a sight in poor homes across Asia, Africa and Latin America. But no one notices the deleterious effects. Over 1.5 million females die prematurely every year by inhaling poisonous fumes as they cook or heat their homes with these organic fuels but catch little attention from governments, policy experts, scientists and medical experts.Adequate evidence exists to indicate that indoor air pollution in India is responsible for a high degree of morbidity and mortality warranting immediate steps for intervention. The intervention programme should include (i) Public awareness; (ii) Change in pattern of fuel use; (iii) Modification in stove design; (iv) Improvement in the ventilation; and (v) Multisectoral approach.

[top] [end]Public Awareness

Women and young girls coughing and choking as they cook food over traditional stoves that burn wood, leaves or dung is a common a sight in poor homes across Asia, Africa and Latin America. But no one notices the deleterious effects.

Over 1.5 million females die prematurely every year by inhaling poisonous fumes as they cook or heat their homes with these organic fuels but catch little attention from governments, policy experts, scientists and medical experts.Indoor air pollution could lead to an epidemic of breathing problems that could kill faster than SARS or the bird flu, warned Kirk Smith, professor of public health at the University of California, Berkeley.The first and the most important step in the prevention of illnesses resulting from biomass fuels is to educate the public, administrators and politicians to ensure their commitment and promoting awareness of the long-term health effects on the part of users. This may lead to people finding ways of minimizing exposure through better kitchen management and infant protection.

[top] [end]Change in Pattern of Fuel Use

The choice of fuel is mainly a matter of availability, affordability and habit. The gobar gas plant which uses biomass mainly dung has been successfully demonstrated to produce economically viable quantities of cooking gas and manure. Recently, the Government of Andhra Pradesh has introduced a programme called the Deepam Scheme to subsidize the cylinder deposit fee for women from households with incomes below the poverty line to facilitate the switch from biomass to LPG. Such schemes will encourage the rural poor to use cleaner fuels. The use of solar energy for cooking is also recommended.

[top] [end]Modification in Stove Design

Use of cleaner fuels should be the long-term goal for the intervention. Till this goal is achieved, efforts should be made to modify the stoves to make them fuel efficient and provide them with a mechanism (eg chimney) to remove pollutants from the indoor environment. Several designs of such stoves have been produced. NIOH study showed significant decrease in levels of SPM, SO2, NOx and formaldehyde with specially designed smokeless stoves in comparison with traditional cooking stoves12. However, they have not been accepted widely. Large scale acceptance of improved stoves would require determined efforts. The most important barriers to new stove introduction are not technical but social.

[top] [end]Improvement in Ventilation

In many parts of the country poor rural folk are provided with subsidized houses under various government/international agencies aided schemes. Ventilation in the kitchen should be given due priority in the design of the houses. In existing houses, measures such as putting a window above the cooking stove? and providing cross ventilation through the door may help in diluting the pollution load.

[top] [end]Multisectoral Approach

Effective tackling of indoor air pollution requires collaboration and commitment between agencies responsible for health, energy, environment, housing and rural development. Indoor air pollution caused by burning traditional fuels such as dung, wood and crop residues causes considerable damage to the health of particularly women and children. There is evidence associating the use of biomass fuel with acute respiratory tract infections in children, chronic obstructive lung diseases, and pneumoconiosis in the residents of Ladakh villages. Lung cancer has been found to be associated with the use of coal in China, however, there is no evidence associating it with the use of biomass fuels. Cataract and adverse pregnancy outcome are the other conditions shown to be associated with the use of biomass fuels. The association of tuberculosis and chronic lung infections with the use of biomass fuels has not been proved. Finally, there is enough evidence to accept that indoor air pollution in India is responsible for a high degree of morbidity and mortality warranting immediate steps for intervention. The first and the most important step in the prevention of illnesses resulting from the use of biomass fuels is to educate the public, administrators and politicians to ensure their commitment for the improvement of public health. There is utmost requirement to collect better and systematic information about actual exposure levels experienced by households in different districts and climatic zones and develop a model for predicting the exposure levels based on fuel use and other household data therein (exposure atlas) to protect the health of children, women and elderly persons.

Household energy has substantial impact in health of rural poor: globally 1.8 million excess deaths and around 4% of the burden of disease in terms of DALYs lost that are attributable to indoor air pollution - most of which falls on the rural poor. Health impacts are mediated through a wide range of inter-related mechanisms from direct (indoor air pollution, burns) to social, economic and environmental issues such as women's time, opportunities for income generation, children's education, environmental stress, etc. The majority of this health burden falls on women and children, with acute respiratory infections being the major disease consequence.

A marked change in policy on household energy is required to improve this situation in short to medium term for the majority of rural poor in many countries. A broad public health framework for understanding and documenting the many and varied health impacts is needed, together with new research to strengthen the evidence base. Although further research on health risks and impacts will help galvanise action and inform decisions about resource allocation for health development, the evidence we currently have shoes that improving access to cleaner and more efficient household energy use among rural poor will deliver marked improvements in health and wellbeing for many millions of families

[top] [end]6. Current Best Practice

Links between energy, health and sustainable development One of the most significant recent developments in this field have been the growing recognition of a set of inter-related issues which address links between energy, health and sustainable development, including:

The importance of environment and health, particularly for children
The restrictions that current patterns of energy use in developing countries place on economic and social development
The impacts of energy use in developing countries on health, particularly in respect of air pollution
The fundamental role of sustainable development in addressing all these issues

The World Health Organisation (WHO) has in recent years developed a broad portfolio of work in this field. This has included a focus on children"s environmental health through the work of the Children"s Environmental Health task force (and post-WSSD the Healthy Environments for Children Alliance), research on the prevention of ALRI through reduced IAP, technical work on air pollution monitoring, risk and quality standards [WHO-PEH], estimates of the GBD associated with IAP (see above), and a range of broader work on household energy and health [WHO 1992; Washington 2000], indicators, and a joint lead role in WSSD preparation [WSSD 2002(a) - Health]. In April 2002, the G8 Environment Ministers met in Banff, Canada, and delivered a statement as part of their work to "advance preparations for the upcoming World Summit on Sustainable Development" [G8 Banff 2002]. Their statement considered environment and development, environment and health, and the national and international governance issues required. The G8 recognised that "The connection between health and the quality of our environment has become a key driver of environmental protection in both developed and developing countries", and that "there is also a growing appreciation of the linkages between environment, health and poverty". In line with theme of the March 2002 WHO Bangkok meeting (above), concern was expressed by the G8 Ministers in particular for children and other vulnerable populations.
The 2002 World Summit on Sustainable Development? (WSSD) was an important focus for bringing these issues together and providing and impetus for action. The meeting was only part of an ongoing process, the impact of which will need to be assessed over time. The preparation for this meeting nevertheless provides some clear insight into the extent to which the issues discussed here are gaining attention, and in particular how awareness of health impacts and linkages might be/is being translated into more effective action by health "systems" as well as though collaboration with other "sectors" at various internationally, nationally and at the local level. The "Framework for Action" documents produced by the WEHAB (Water, Energy, Health, Agriculture and Biodiversity) working groups are a useful guide to the approach. Two of these working group reports were, Health and Environment led by WHO and UNICEF [WSSD/WEHAB Health 2002] and Energy led by UNDESA, UNDP and UNIDO [WSSD/WEHAB Energy 2002]. In identifying the challenges, both reports emphasized the linkages between energy, health and development with the problems of household energy, IAP and poverty (especially in sub-Saharan Africa) receiving attention.

Among the more clearly identified actions resulting from WSSD in respect of this topic are (a) the Partnership for Clean Indoor Air (PCIA), a US funded initiative led by the Environmental Protection Agency, and (b) the Healthy Environments for Children Alliance (HECA), led by WHO.

The PCIA focuses on four core aspects of the problem:

Social and behavioural barriers
Market development
Technology design: develop a certification rganization (to be self-sustaining over time) to identify, and develop design guidelines or standards for, efficient and needs-responsive cooking and heating technologies and ventilation systems.
Health effects research: identify and pursue priority research needs to expand and refine knowledge of health effects of indoor cooking and heating practices in a variety of settings (e.g. fuel type, stove type, ventilation system).

[top] [end]7.Areas of Research

[top] [end]Social and economic impacts on health

Lack of access to more modern fuels and appliances limits the quality of life and opportunities for income generation in a variety of ways. For example, in many poor rural homes, lighting may be very restricted and provided only by the fire, candles, or simple kerosene wick lamps which can be a significant source of pollution. The lack of light restricts activities in the home, including children's homework, reading and opportunities for income-generating activities. Lack of access to electricity further restricts the use of a wide range of appliances that can contribute to food safety (refrigerators), communication/education, leisure (radio, TV), and economic activity. Dependence on biomass fuels can affect the wellbeing of children in other ways. For example, it is not uncommon for older children to help their mothers in collecting fuel, thus missing school attendance and also being exposed to the risk of physical injury.

[top] [end]Gender, household energy and health

In almost all developing countries it is women who provide fuel for the family and carry out cooking and many other tasks that require energy use in the home. Studies show that fuel collection takes, on average, from 30 minutes to 2 hours a day, although this can be longer when fuel is scarce. The time spent in collecting wood and other fuels has an 'opportunity cost' for women, especially during busy agricultural periods (World Energy Council 1999). Carrying heavy loads of wood exposes women to injury from falls (bruises and fractures) and the risk of miscarriage; in areas of war and civil unrest the women may be exposed to violence as well as injury from land mines (WHO 1992). Because of their work in the kitchen, often close to the fire, women have more exposure to pollution than other family members, which has been estimated at between 4 and 7 hours per day in rural Guatemala, for example (Engle et al. 1997), although in the coldest highland areas of Asia and South America it may be considerably longer.

[top] [end]Local and global environments

The damage to the environment can impact on health in a wide variety of ways, from increasing pressure on food production, water shortages, etc., in the local setting, to the potentially widespread and major impacts that global warming may have - particularly on the countries of sub-Saharan Africa. Household energy supply and use in sub-Saharan Africa has impacts on both local and global environments, although the latter are small relative to industrialised countries, and in general environmental impacts should be viewed in the wider context of poverty, population pressures, and political factors.

[top] [end]Local environment

It has often been assumed that, in many areas, the use of wood fuel is the major cause of deforestation and environmental damage that results from this. However, it is generally the case that, in rural areas, wood fuel is gathered rather than cut from the trees; agricultural practices and the need for building materials, combined with population pressure, are therefore the most important factors in deforestation. Nevertheless, pressure on forests from the use of wood fuel is a problem. In peri-urban and urban areas, the use of wood requires transport over longer distances, so increasing the demand for charcoal which is leading to forest depletion in rural areas providing fuel to cities. Charcoal is an important fuel for many poor peri-urban and urban populations in sub-Saharan Africa.

[top] [end]Global environment

The burning of biomass, like all combustion of carbon fuels, produces carbon dioxide and other gases which contribute to global warming, which is expected to increase the risk of vector borne disease, food and water shortage, population dislocation, etc. However, the low energy use of homes in countries such as those in sub-Saharan Africa means that their contribution to the global output of greenhouse gases is relatively small. In 1995, per capita CO2 production was estimated at less than 2 tonnes for developing countries, compared to 12 tonnes for developed countries and 20 tonnes for the USA (Reddy et al. 1997). That said, it is nonetheless a contributory factor and one that can be expected to grow. Furthermore, although it might be assumed that since biomass is renewable, the replacement of wood burned should result in a neutral carbon balance - the CO2 released from burning being taken up as new trees grow. However, since the stoves used in developing country homes have a low efficiency of around 15%, with (for example) nearly 10% of the energy of wood being lost as products of incomplete combustion (PICs). These PICs include methane, which has a greenhouse effect many times greater than Carbon dioxide, (CO2). As a result, the two main factors that influence the global warming effect of biomass use are the combustion efficiency of the stove and the effectiveness of energy forest management.

[top] [end]Poverty

Poverty remains a very important, probably the most important, determinant of health, underlying all other issues discussed so far - and this is clearly demonstrated by the close inter-relationship between household energy, poverty and health. Reliance on simple biomass fuels holds back development because it impairs health and restricts opportunities for education and income generation, while poverty prevents households breaking out of this reliance because poor families cannot afford the higher cost of cleaner fuels and the appliances required.

Furthermore, there is evidence that, over time, the cost of using cleaner fuels is not necessarily higher, but poverty prevents people from taking advantage of this fact. The reason is that poor families have very limited financial assets and generally find it difficult to invest money 'up-front' to obtain the appliances needed for burning kerosene cleanly (with pressurized stoves), for gas or electricity, or to buy the fuel in sufficient quantity to benefit from lower unit prices. As a result, poor people may spend a higher proportion of income on fuel for cooking and heating than those who are better off, in addition to the time lost in collecting and using these less convenient fuels (Reddy et al. 1997).

Figure 2 summarizes the wide range of factors that both influence and result from dependence on biomass fuels and inefficient, polluting stoves. There are of course many inter-relationships that are not indicated in the diagram. The important message, however, is that patterns of household energy use in poor communities impact on a very wide range of key health, social, gender, economic and environmental issues, and that action therefore has the potential for considerable benefits in terms of development and health improvement

Figure 2:Range of factors that both influence and result from dependence on biomass fuels and inefficient, polluting stoves

[top] [end]Burden of disease

The review of the health effects of indoor air pollution discussed in Section 3 above provides information on the risk to individuals associated with exposure to smoke from biomass fuels (and coal). It has been noted that very large numbers of people, mainly women and young children, are exposed to this pollution in a wide range of rural as well as peri-urban and urban settings. This implies that a very substantial public health impact can be expected. While acknowledging the uncertainty that exists in the estimates of health risk, levels of personal exposure, numbers of people exposed and disease rates, it is nevertheless possible to combine this information - so long as this is done cautiously - to derive an estimate of the overall 'public health burden' resulting from indoor air pollution in these settings. This approach is encapsulated in the global burden of disease (GBD) project (Murray et al).

Current estimates indicate that in developing countries indoor air pollution is responsible for around 1.8 million extra deaths and the loss of just over 50 million DALYs (Smith et al. 2000). These figures are equivalent to 4.7% of total deaths and around 4% of DALYs lost for these areas of the world (Table 2). For sub-Saharan Africa, some 420 thousand deaths and 14 million DALYs are accounted for. Most of this burden is due to acute respiratory infections, especially in poor rural populations..

Table 2. Percentage of total burden in listed regions attributable to solid fuel use

Region	Deaths	ARI (%)	DALYs	ARI (%)
India	5.3%	81	5.5%	87
China	5.8%	25	4.5%	50
Other Asia & Pacific Islands	3.8%	75	3.7%	85
Sub-Saharan Africa	5.2%	85	4.9%	90
Latin America	1.0%	71	0.9%	82
Middle East and North Africa	3.6%	89	3.7%	93
Total	4.7%	67	4.3%	81

These are fairly conservative estimates based on disease conditions for which there is moderately good evidence (ARI, COLD and Ca lung - the latter for coal use). The evidence for other health impacts such as TB, low birth weight, etc., is not thought sufficiently robust for inclusion at this time. Furthermore, these estimates account only for the health effects of indoor air pollution, and do not yet take account of the wider health impacts of household energy use in poor countries discussed in sections 3.2-3.5.

[top] [end]8.Weblinks

[top] [end]9. Resources on HEDON

[top] [end]10. Organizations and People

[top] [end]Sources

This article is based upon two articles by Dr Nigel Bruce for Sparknet, and adapted by HEDON members.

Categories: Leading Issues| Health| Indoor Air Pollution

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