Indoor air pollution and health
- Around 3 billion people cook and heat their homes using open fires and leaky stoves burning biomass (wood, animal dung and crop waste) and coal.
- Nearly 2 million people die prematurely from illness attributable to indoor air pollution from household solid fuel use.
- Nearly 50% of pneumonia deaths among children under five are due to particulate matter inhaled from indoor air pollution.
- More than 1 million people a year die from chronic obstructive respiratory disease (COPD) that develop due to exposure to such indoor air pollution.
- Both women and men exposed to heavy indoor smoke are 2-3 times more likely to develop COPD.
Indoor air pollution and household energy: the forgotten 3 billion
Around 3 billion people still cook and heat their homes using solid fuels in open fires and leaky stoves. About 2.7 billion burn biomass (wood, animal dung, crop waste) and a further 0.4 billion use coal. Most are poor, and live in developing countries.
Such cooking and heating produces high levels of indoor air pollution with a range of health-damaging pollutants, including small soot particles that penetrate deep into the lungs. In poorly ventilated dwellings, indoor smoke can be 100 times higher than acceptable levels for small particles. Exposure is particularly high among women and young children, who spend the most time near the domestic hearth.
Impacts on health
Nearly 2 million people a year die prematurely from illness attributable to indoor air pollution due to solid fuel use (2004 data). Among these deaths, 44% are due to pneumonia, 54% from chronic obstructive pulmonary disease (COPD), and 2% from lung cancer.
Nearly half of deaths among children under five years old from acute lower respiratory infections (ALRI) are due to particulate matter inhaled from indoor air pollution from household solid fuels (WHO, 2009).
Chronic obstructive pulmonary disease
Women exposed to heavy indoor smoke are three times as likely to suffer from chronic obstructive pulmonary disease (e.g. chronic bronchitis), than women who use cleaner fuels. Among men (who already have a heightened risk of chronic respiratory disease due to their higher rates of smoking), exposure to indoor smoke nearly doubles that risk.
Approximately 1.5% of annual lung cancer deaths are attributable to exposure to carcinogens form indoor air pollution. As with bronchitis, the risk for women is higher, due to their role in food preparation as well as their comparatively lower rates of smoking. Women exposed to indoor smoke thus have double the risk of lung cancer in comparison with those not exposed.
Other health impacts
More generally, small particulate matter and other pollutants in indoor smoke inflame the airways and lungs, impairing immune response and reducing the oxygen-carrying capacity of the blood.
There is also evidence of links between indoor air pollution and low birth weight, TB, ischaemic heart disease, nasopharyngeal and laryngeal cancers.
Impacts on health equity, development and climate change
Without a substantial change in policy, the total number of people relying on biomass fuels will increase to from today's 2.4 billion to 2.7 billion by 2030 (IEA, 2010). This will increase the number of people at risk of adverse health effects from indoor air pollution. The use of polluting fuels also poses a major burden on development.
- Fuel gathering consumes considerable time for women and children, limiting other productive activities and taking children away from school. In less secure environments, women and children are at risk of injury and violence during fuel gathering.
- Non-renewable harvesting of biomass contributes to deforestation and thus climate change. Methane and black carbon (sooty particles) emitted by inefficient stove combustion are powerful climate change pollutants.
- The lack of access to electricity for at least 1.4 billion of households (many of whom then use kerosene lamps for lighting), creates other health risks, e.g. burns and injuries, as well as constraining other opportunities for health and development, e.g. studying or engaging in small crafts and trades, which require adequate light.
WHO is a leading partner in a new Global Alliance for Clean Cookstoves, led by the United Nations Foundation, and involving a range of UN agencies, donors, NGOs, civil society and country partners. The Alliance is promoting improved biomass cookstove designs that can substantially reduce indoor air pollution, as well as biogas stoves that very efficiently burn methane produced by sewage and animal waste as a clean household fuel.
WHO is leading efforts to evaluate which of these new technologies produce the least emissions and thus are most optimal for health. WHO is also providing technical support to countries in their own evaluations and scale up of healthy-promoting stove technologies.
Other WHO activities include the following:
New indoor air quality guidelines
WHO is preparing new indoor air quality guidelines for household fuel combustion. These will add health-based guidance about fuels, stove technologies and other strategies (e.g. ventilation) for reducing exposure. These build upon existing WHO outdoor air quality guidelines and recently published WHO guidance on levels of specific indoor pollutants.
Household energy database
The WHO household energy database is used to monitor global progress in the transition to cleaner fuels and improved stoves and to contribute to assessments of disease burden from household energy.
Health and climate change co-benefits calculator
WHO is supporting the development of web-based tools that can help scientists and health professionals estimate the impact of new programmes or technologies in terms of anticipated health benefits (deaths/disability) and reductions in pollutants.
Research and programme evaluation
WHO is working with countries, researchers and other partners to harmonize methods of evaluation across settings so that health impacts are assessed consistently and rigorously and also incorporate economic assessment of health benefits.
Leadership and advocacy in the health community
WHO is working to integrate guidance and resources for supporting clean household energy into other global child health initiatives and decision-support tools , such as the Lives-Saved tool (LiST), as well as into other aspects of WHO's own health policy guidance. WHO advocates about the compelling health arguments for cleaner household energy in a range of global forums addressing maternal and child health issues related to pneumonia as well as forums concerned with non-communicable diseases in adults. This can help awareness of the importance of provision and scale up of cleaner household energy as a core preventive public health measure, to reduce childhood respiratory illness and improve adult lung health.
Supporting the Millennium Development Goals
- Tackling indoor air pollution will help achieve the Millennium Development Goals (MDGs), in particular MDG 4 (reduce child mortality) and MDG 5 (improve maternal health).
- It will also contribute to gender equality (MDG 3) as well as freeing women's time for income generation that helps eradicate extreme poverty and hunger (MDG 1).
- Finally, clean household energy can help ensure environmental sustainability (MDG 7). WHO reports annually on the proportion of the population using solid fuels for cooking as a key indicator for assessing progress in health and development.