Acute lower respiratory infections
There is consistent evidence that exposure to biomass smoke increases the risk of acute lower respiratory infections (ALRI) in childhood, particularly pneumonia. Globally, ALRI represent the single most important cause of death in children under 5 years and account for at least 2 million deaths annually in this age group.
Chronic obstructive pulmonary disease
Indoor air pollution is considered a risk factor for chronic bronchitis (CB) and chronic obstructive pulmonary disease (COPD - progressive and incompletely reversible airflow obstruction). The association between exposure to biomass smoke and CB/COPD has been particularly well established for women.
Smoke from both coal and biomass contains substantial amounts of carcinogens (chemical substances known to increase the risk of cancer). A consistent body of evidence has shown that women exposed to smoke from coal fires in the home have an elevated risk of lung cancer. This effect has not been demonstrated among populations using biomass, but the presence of carcinogens in the smoke implies that the risk may be present.
Other health outcomes
There is emerging evidence which suggests that indoor air pollution in developing countries may also increase the risk of other important child and adult health problems, although this evidence is tentative and based on fewer studies. It includes conditions such as:
- low birthweight and perinatal mortality (still births and deaths in the first week of life)
- otitis media (middle ear infection) and other acute upper respiratory infections
- nasopharyngeal cancer
- laryngeal cancer
- cataract (blindness)
- cardiovascular disease
Status of evidence
The table summarizes the status of evidence on the health effects of indoor air pollution.