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.
(Source: WHO Fact sheet N°292)