Indoor air pollution

September 2011

Key Facts

  • Nearly 2 million people globally die prematurely from illness attributable to indoor air pollution from household solid fuel use (wood, animal dung and crop waste) and coal.
  • 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), due to exposure to indoor air pollution.

3 billion at risk

  • Around 3 billion people globally 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 globally 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).
  • 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 globally are attributable to exposure to carcinogens from 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

  • 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.

Impact on health equity, development and climate change

  • 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 households (many of whom instead use kerosene lamps for lighting), creates other health risks, e.g. burns and injuries, as well as constraining other opportunities for health and development, such as studying or engaging in small crafts and trades, which require adequate light.

WHO's response

  • WHO is a leading partner in the 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 produces the least emissions and thus are most optimal for health. WHO is also providing technical support to countries in their own evaluations and scaling-up of healthy-promoting stove technologies.