Indoor air pollution and household energy: the forgotten 3 billion

Around 3 billion people still cook using solid fuels (such as wood, crop wastes, charcoal, coal and dung) and kerosene in open fires and inefficient stoves. Most of these people are poor, and live in low- and middle-income countries.

These cooking practices are inefficient, and use fuels and technologies that 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

3.8 million people a year die prematurely from illness attributable to the household air pollution caused by the inefficient use of solid fuels and kerosene for cooking. Among these 3.8 million deaths:

27% are due to pneumonia

18% from stroke

27% from ischaemic heart disease

20% from chronic obstructive pulmonary disease (COPD)

8% from lung cancer.

Pneumonia

Exposure to household air pollution almost doubles the risk for childhood pneumonia and is responsible for 45% of all pneumonia deaths in children less than 5 years old. Household air pollution is also risk for acute lower respiratory infections (pneumonia) in adults, and contributes to 28% of all adult deaths to pneumonia.

Chronic obstructive pulmonary disease

One in four or 25% of 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 twice as likely to suffer from COPD than women who use cleaner fuels and technologies. Among men (who already have a heightened risk of COPD due to their higher rates of smoking), exposure to household air pollution nearly doubles that risk.

Stroke

12% of all deaths due to stroke can be attributed to the daily exposure to household air pollution arising from cooking with solid fuels and kerosene.

Ischaemic heart disease

Approximately 11% 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.

Lung cancer

Approximately 17% of lung cancer deaths in adults are attributable to exposure to carcinogens from household air pollution caused by cooking with kerosene or 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 policy change, the total number of people lacking access to clean fuels and technologies will remain largely unchanged by 2030 (International Energy Agency, 2017 (1)) and therefore hinder the achievement of the 2030 Agenda for Sustainable Development.

Fuel gathering increases the risk of musculoskeletal damage, consumes considerable time for women and children, limits other productive activities (such as income generation) and takes 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.

Many of the fuels and technologies used by households for cooking, heating and lighting present safety risks. The ingestion of kerosene is the leading cause of childhood poisonings, and a large fraction of the severe burns and injuries occurring in low- and middle-income countries are linked to household energy use for cooking, heating and/or lighting.

The lack of access to electricity for 1 billion people (many of whom then use kerosene lamps for lighting) exposes households to very high levels of fine particulate matter. The use of polluting lighting fuels introduces other health risks, such as burns, injuries, poisonings, and constrains other opportunities for health and development, like studying or engaging in small crafts and trades, which require adequate lighting.

WHO response

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 through direct consultations and workshops on household energy and health. This is further complemented by the ongoing development of the Clean Household Energy Solutions Toolkit (CHEST) to support the implementation of WHO Guidelines for indoor air quality: household fuel combustion. CHEST is a suite of tools and information resources that help countries identify stakeholders working on household energy and/or public health to design, implement and monitor policies addressing household energy.

Guidelines for indoor air quality: household fuel combustion

To ensure healthy air in and around the home, WHO’s Guidelines for indoor air quality: 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 and adoption 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 in households. It also supports assessments of disease burden from the household air pollution generated from the use of polluting fuel and technologies. Currently the database includes housing data from more than 1100 surveys, representing 157 countries. It has been expanded to include information on household fuels and technologies used for heating and lighting.

As the custodial agency for Sustainable Development Goal Indicator 3.9.1 (mortality rate from the joint effects of household and ambient air pollution) and 7.1.2 (population with primary reliance on clean fuels and technologies), WHO uses the Household energy database to derive estimates for tracking progress towards achieving universal clean energy access and related health impacts.

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 incorporate economic assessment of health benefits.

Leadership and advocacy in the health, energy and climate community

Health sector

In May 2015, the World Health Assembly unanimously adopted a resolution on air pollution and health, calling for the integration of health concerns into national, regional and local air pollution-related policies. The following year, the World Health Assembly adopted a “Roadmap for Enhanced Action,” calling for increased cross-sector cooperation to address the health risks of air pollution.

Building on this mandate, 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 emphasizes 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. This advocacy can help increase 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). Achieving this goal could prevent millions of deaths and improve the health and well-being of the billions of people relying on polluting technologies and fuels for cooking, heating and lighting.

To better assess the health risks of household energy use, as well as differentiated gender impacts from household energy practices, 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 questions for national censuses and surveys. The effort will ensure that surveys 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 disaggregated by sex.

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.

(1) WEO-2017 Special Report: Energy Access Outlook, International Energy Agency, 2017 (https://webstore.iea.org/weo-2017-special-report-energy-access-outlook)