Indoor air pollution (IAP) remains a large global health threat. One half of the world population, and up to 95% i
n poor countries, continues to rely on solid fuels, including biomass fuels (wood, dung, agricultural residues) and coal, to meet their energy needs. Cooking and heating with solid fuels on open fires or on traditional stoves generates high levels of health-damaging pollutants, such as particulates and carbon monoxide. As women are primarily responsible for cooking, and as children often spend time with their mothers while they are engaged in cooking activities, women and young children are disproportionately affected. For example, the World Health Report (2002) estimates that acute respiratory infection (ARI) is one of the leading causes of child mortality in the world, accounting for up to 20% of fatalities among children under five, almost all of them in developing countries (IAP is thought to cause about one-third of ARI cases). This makes solid fuels the second most important environmental cause of disease after contaminated waterborne diseases (Bruce et al, 2006) and the fourth most important cause of overall excess mortality in developing countries after malnutrition, unsafe sex, and waterborne diseases (Bruce et al, 2006).
The relationship between air pollution and health came into focus from the studies that look at the impacts of ambient air pollution levels in the developed world. The studies indicates that these ambient air pollution levels affect human health, especially the health of young children and infants.
In addition to impacts on mortality, IAP may have long lasting effects on general health and well-being: early exposure to IAP during childhood may stifle lung development, suggesting that the cost of this pollution may continue later in life. In fact, a growing literature indicates that environmental insults at early ages can have long lasting influences on human health and productivity.
More than a third of humanity, 2.4 billion people, burn biomass (wood, crop residues, charcoal and dung) for cooking and heating. When coal is included a total of 3 billion people - half the world’s population - cook with solid fuel.
Around two-thirds of women with lung cancer in China and India are non-smokers.
The smoke from burning these fuels turns kitchens in the world’s poorest countries into death traps. Indoor air pollution from the burning of solid fuels kills over 1.5 million people, predominately women and children, each year. This is more than three people per minute. It is a death toll almost as great as that caused by unsafe water and sanitation, and greater than that caused by malaria. Smoke in the home is one of the world’s leading child killers, claiming nearly one million children’s lives each year.
Globally, reliance on solid fuels is one of the 10 most important threats to public health. Indoor Air Pollution in India results from burning biomass (like wood, crop waste and animal dung) during cooking in the home. The toxic emissions and smoke from this cooking claims as many as 500,000 lives in India every year, most of whom are women and children due to their increased exposure in the home.
One person around the world dies every 20 seconds from the cumulative effects of IAP, resulting in approximately 1.5 million deaths per year. India accounts for 80% of the 600,000 premature deaths that occur in south-east Asia annually due to exposure to IAP. The World Health Organisation estimates that pollution levels in rural Indian kitchens are 30 times higher than recommended levels and six times higher than air pollution levels found in New Delhi.
A survey assessed respiratory function using spirometery tests. The study reveals that CO levels and the reported health symptoms were reduced among women who received planchas. After about 16 months, a little over half (52.3 percent) of women in the treatment group stated that their health had improved, compared with a quarter (23.5 percent) of the control group. Women in the treatment group had reductions of sore eyes, of headaches, and of sore throats as compared to the control. Children in the treatment group experienced reductions in crying and of sore eyes.
Women and children hit hardest
Indoor air pollution is not an indiscriminate killer. It is the poor who rely on the lower grades of fuel and have least access to cleaner technologies. Specifically, indoor air pollution affects women and small children far more than any other sector of society. Women typically spend three to seven hours per day by the fire, exposed to smoke, often with young children nearby.
Over half of all people cooking on biomass live in India and China. This is a chronic problem for people living in rural areas of developing countries, but not exclusively - there is a growing problem in the cities as well.
A problem set to get worse
On current trends an extra 200 million people worldwide will rely on biomass for their cooking and heating needs by 2030, according to the International Energy Agency. In parts of Central Asia where gas and electricity used to be available people are reverting back to using biomass as their main fuel source. In Tajikistan since 1991 the incidence of acute respiratory infection, the world’s greatest child killer, has risen by 35% largely as a result of burning wood indoors.
The effects of smoke on health
In the cities of the industrialized world air pollution has long been recognized as a major health hazard. A great deal of time and effort is put into measures that will reduce exposure to air pollution. Yet in poor people’s homes throughout the developing world levels of exposure to pollutants are often 100 times greater than recommended maximums.
The use of poorly ventilated, inefficient stoves ‘can have the same adverse health impacts as smoking two packs of cigarettes a day’.
- United Nations Development Programme.
Illnesses caused by indoor air pollution include acute lower respiratory infection. A child is two to three times more likely to contract acute lower respiratory infection if exposed to indoor air pollution. Women who cook on biomass are up to four times more likely to suffer from chronic obstructive pulmonary disease, such as chronic bronchitis. Lung cancer in women in China has been directly linked to use of coal burning stoves. In addition there is evidence to link indoor air pollution to asthma, tuberculosis, low birth weight and infant mortality and cataracts.
Reducing lethal levels of smoke
Billions of people would lead a healthier life if their exposure to lethal levels of smoke were reduced. Public awareness of the health risks of smoke is a crucial first step. The most effective way to reduce smoke in the home is to switch to a cleaner fuel, such as liquid petroleum gas (LPG), kerosene or biogas.
However, the vast majority of people at risk are too poor to change to a cleaner fuel, or have no access to modern fuels. In these homes, the answer will be to reduce exposure, for example by using well designed stoves, or smoke hoods which can reduce indoor air pollution by up to 80%.
Though simple, low-cost solutions are available, a technical fix alone is not the answer. Cooking is a deeply cultural and domestic task and communities themselves, particularly the women, must be directly involved in developing solutions that suit their circumstances.
