Indoor air pollution is an aspect human health that most researchers and environment activists have not given adequate attention, whereas billions of dollars have been channeled in research into harmful effects of cigarette smoke and outdoor pollution. Wood, dung, stove and grass are used daily in about half of the world's households especially in developing countries as energy for cooking and heating. In most parts of the Third World they are burnt in open fires or inefficient stoves in poorly ventilated kitchens. The result is a toll in death and ill health far greater than the more often discussed outdoor air pollution.
This smoke contains many harmful constituents such as respirable particulates and carbon monoxide, exposure to which can cause or contribute to acute respiratory infections, pneumonia, tuberculosis, lower birth weights, cataract, and nervous and muscular fatigue.
Smoke, especially coal smoke, also contains sulfur and nitrogen oxides and hydrocarbons which can lead to cancer. Women and children are most exposed to high levels of harmful smoke and suffer the most serious health damage; respiratory infections alone cause between 4 and 5 million deaths per year among small children, which is equal to or marginally less than deaths from diarrhea diseases. Some 1.9 million additional deaths each year are blamed on rural indoor pollution through suspended particulate matter and another 450,000 deaths are attributed to urban indoor air pollution. African countries and India have the worst record in rural homes, while Latin America, India and China are worst in urban interiors. For example, In Gambia it was found that girls aged under five carried on their mother's back during cooking (in smoky cooking huts) had a six times higher risk - a substantially higher risk factor than if their parents smoked.
It is worthy to note that some Non-governmental organizations and some influential women in Nigeria have embarked in a campaign for clean cooking solutions.
Clean cooking solutions are those technologies, fuels, equipment and practices that address the health and environmental impacts associated with traditional cooking with firewood. These could take the form of improved and efficient wood and charcoal burning stoves, or cooking gas. In most cases, the shift to clean cook stoves reduces cooking costs and health impacts for families. It comes in various sizes and anticipates cultural affinity for certain ways of cooking, hence its adaptability to wood, kerosene and gas.