For centuries people have suffered polluted and stale air inside cramped dwellings and huts. A significant contributor to indoor air pollution in many parts of the world is the smoke and fumes from burning dung, bark and wood indoors on open fires or simple stoves used for cooking, and for heating in alpine regions where indoor air pollution is aggravated by limiting ventilation to conserve heat.
New problems of indoor air pollution are arising from synthetic materials and structural techniques, and from construction materials whose constituents are potentially toxic or irritant and hence likely to produce allergic responses. The causes of such indoor pollution are not precise. The term may also be extended to cover tobacco smoke and body odour. It may include the combined effects of office machines and carpeting. Recent reports suggest that there is both direct and circumstantial evidence that exposure of the public to indoor air pollutants are large enough and widespread enough to account for a substantial amount of sickness and premature death.
Improvements in epidemiological research in the 1990s have revealed that human health may be affected by exposure to much lower levels of some common air pollutants than previously believed. Although eliminating the pollutants may not be feasible in the near future, air quality management should attempt to minimize the risk. This is a major conceptual development that became apparent in the mid-1990s.
The need for energy conservation has influenced the rate of air change in a building; better draught control can have the result that higher levels of pollutants now occur. In the USA it has been estimated that passive smoking aggravates indoor pollution to the extent of tens of billions of dollars in medical costs and absenteeism. The risks of of indoor pollution from tobacco smoke may be twice as great as the danger from radon gas and more than 100 times as great as from cancer-causing outdoor pollutants.
Indoor air pollution remains a very real public health hazard for hundreds of millions of people living in developing countries. It is the women, children and the elderly who are at greater risk of damaging their health through a whole array of diseases varying from asthma to cancer triggered off by indoor air pollution. Smoke from indoor cooking fires that burn fuelwood and dung is estimated to cause the death of 4 million children each year worldwide. Indoor air pollution is the commonest cause of occupationally related respiratory disease among women in developing countries; in 1985 at least 400 million women and girls were afflicted with life-shortening chronic respiratory disease due to inhaling toxic smoke and fumes from combusted biomass fuel. This is a common problem in northern India and Pakistan, in the highlands of east and central Africa, and in Papua New Guinea.
People in developing countries face larger amounts of indoor pollutants, such as sulphur and nitric oxides and arsenic compounds, due to greater exposure to open fires which burn biomass, coal or wood as fuel. Indoor pollution, a more severe threat to women and children who spend more time indoors, causes respiratory disorders and is also linked to heart and lung disease mortality. A study in India and Nepal demonstrates that cardiovascular disease is more common among women who have been exposed to indoor pollutants (WHO 1992).
Indoor air pollution caused by the widespread use of biomass as a cooking fuel is also a major contributor to the high incidence of respiratory diseases because of the exposure to smoke and other pollutants in a confined space. In sub-Saharan Africa, biomass use is expected to provide nearly 80 per cent of the total energy used even in 2010.In a report released October 2017 by Healthy Building Network (HBN), multiple toxic substances were identified in ordinary broadloom carpets and carpet tiles. The HBN, a non-profit organization that works towards hazardous chemical transparency, lists 44 harmful chemicals found in carpet facing, carpet backing, carpet padding and adhesives. For example, stain repellent ingredients can include PFAS – poly– and perfluoroalkyl substances – that are classified as reproductive and developmental toxicants. Antimicrobial preservative treatments are intended to protect carpets from biological damage due to mold, mildew and bacteria; these may contain triclosan, an endocrine disruptor, as well as formaldehyde, a known carcinogen. Phthalates, which are added to carpet backings to make them more flexible, are carcinogens that can cause developmental problems.