Indoor air pollution and household energy: the forgotten 3 billion
Around 3 billion people still cook and heat their homes using solid fuels (i.e. wood, crop wastes, charcoal, coal and dung) in open fires and leaky stoves. Most are poor, and live in low- and middle-income countries.
Such inefficient cooking fuels and technologies produce high levels of household 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 fine particles. Exposure is particularly high among women and young children, who spend the most time near the domestic hearth.
Impacts on health
4.3 million people a year die prematurely from illness attributable to the household air pollution caused by the inefficient use of solid fuels (2012 data) for cooking. Among these deaths:
- 12% are due to pneumonia
- 34% from stroke
- 26% from ischaemic heart disease
- 22% from chronic obstructive pulmonary disease (COPD), and
- 6% from lung cancer.
Exposure to household air pollution almost doubles the risk for childhood pneumonia. Over half of deaths among children less than 5 years old from acute lower respiratory infections (ALRI) are due to particulate matter inhaled from indoor air pollution from household solid fuels (WHO, 2014).
Nearly one quarter of all premature deaths due to stroke (i.e. about 1.4 million deaths of which half are in women) can be attributed to the chronic exposure to household air pollution caused by cooking with solid fuels.
Ischaemic heart disease
Approximately 15% of all deaths due to ischaemic heart disease, accounting for over a million premature deaths annually, can be attributed to exposure to household air pollution.
Chronic obstructive pulmonary disease
Over one-third of premature deaths from chronic obstructive pulmonary disease (COPD) in adults in low- and middle-income countries are due to exposure to household air pollution. Women exposed to high levels of indoor smoke are more than 2 times as likely to suffer from COPD than women who use cleaner fuels. Among men (who already have a heightened risk of COPD due to their higher rates of smoking), exposure to indoor smoke nearly doubles (i.e. 1.9) that risk.
Approximately 17% of annual premature lung cancer deaths in adults are attributable to exposure to carcinogens from household air pollution caused by cooking with solid fuels like wood, charcoal or coal. The risk for women is higher, due to their role in food preparation.
Other health impacts and risks
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 household air pollution and low birth weight, tuberculosis, cataract, nasopharyngeal and laryngeal cancers.
Mortality from ischaemic heart disease and stroke are also affected by risk factors such as high blood pressure, unhealthy diet, lack of physical activity and smoking. Some other risks for childhood pneumonia include suboptimal breastfeeding, underweight and second-hand smoke. For lung cancer and chronic obstructive pulmonary disease, active smoking and second-hand tobacco smoke are also main risk factors.
Impacts on health equity, development and climate change
Without a substantial change in policy, the total number of people relying on solid fuels will remain largely unchanged by 2030 (World Bank, 2010). The use of polluting fuels also poses a major burden on sustainable development.
- Fuel gathering consumes considerable time for women and children, limiting other productive activities (e.g. income generation) and taking children away from school. In less secure environments, women and children are at risk of injury and violence during fuel gathering.
- Black carbon (sooty particles) and methane emitted by inefficient stove combustion are powerful climate change pollutants.
- The lack of access to electricity for at least 1.2 billion people (many of whom then use kerosene lamps for lighting) exposes households to very high levels of fine particulate matter, as well introduces other health risks, e.g. burns, injuries and poisonings from fuel ingestion, constraining other opportunities for health and development, e.g. studying or engaging in small crafts and trades, which require adequate lighting.
WHO provides technical support to countries in their own evaluations and scale-up of health-promoting household fuels and technologies. WHO is building capacity at the country and regional level to address household air pollution with workshops and the development of tools to help design, implement and monitor policies addressing household energy.
Other WHO activities include the following:
New indoor air quality guidelines for household fuel combustion
To ensure healthy air in and around the home, WHO’s new indoor air quality guidelines for household fuel combustion provide health-based recommendations on the types of fuels and technologies to protect health as well as strategies for the effective dissemination of such home energy technologies. These build upon existing WHO outdoor air quality guidelines and 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 stove combinations, as well as contributes to assessments of disease burden from household energy and the energy access situation in low and middle-income countries. Recently this database has been expanded to include, in addition to extensive data on cooking, information on household fuels and technologies used for heating lighting and other impacts like time spent collecting fuel. The WHO Household Energy Database is used to monitor global progress in the transition to cleaner fuels and improved stoves as well as contribute to assessments of disease burden from household energy and the energy access situation in developing countries.
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, energy and climate community
WHO is working to integrate guidance and resources for supporting clean household energy into global health initiatives and decision-support tools, such as the Global Action Plan for Pneumonia and Diarrheal Disease (GAPPD), or Global Strategy for Women and Children’s Health, 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 noncommunicable diseases in adults. This can help awareness of the importance of providing and scaling up of cleaner household energy as a core preventive public health measure.
Health and climate change
WHO is a partner of the Climate and Clean Air Coalition to Reduce Short-Lived Climate Pollutants (CCAC). As a member of the CCAC’s health task force, WHO is providing technical support for harnessing health benefits from actions to reduce short-lived climate pollutants, and working to scale up health sector engagement to address such pollutants and improve air quality.
Health, energy and sustainable development
Reductions in air pollution-related disease burden (both for household and outdoor) will be used to monitor the progress towards attaining the Sustainable Development Goal on Health (SDG 3).
Ensuring universal access to clean fuel and technologies is a target of the Sustainable Development Goal on energy (SDG 7). If this target is met it could prevent millions of deaths and improve the health and well-being of the billions of people relying on polluting fuels and technologies for cooking, heating and lighting.
To better assess the health risks, as well as differentiated gender impacts from household energy, WHO is leading an effort with countries and surveying agencies (e.g. USAID’s DHS, UNICEF’S MICS, World Bank’s LSMS) to enhance, harmonize and pilot new questions for national censuses. The effort will also survey to better capture information on all the fuels and technologies used in the home for cooking, heating and lighting, as well as other impacts like time lost to fuel collection.
WHO also contributes to the development and updating of the global tracking framework used to measure progress toward the UN Secretary-General’s Sustainable Energy for All initiative target of universal access to clean energy by 2030.
WHO also supports international initiatives to improve air pollution and related health impacts such as the Global Alliance for Clean Cookstoves and the Climate Clean Air Coalition.