The New Nation - Internet Edition

Shanta Dutta

We usually think of air pollution as being outdoors, but the air in our house or office could also be polluted. A person may inhale more air pollutants with each breath in indoor than that of outside. Sources of indoor pollution include- biological contaminants like mold and pollen , smoke from fuel burning, tobacco smoke, household products and pesticides, gases such as radon and carbon monoxide, materials used in the building such as asbestos, formaldehyde and lead.Indoor air problems can be subtle and do not always produce easily recognized impacts on health. Different conditions are responsible for indoor air pollution in the rural and the urban areas.

In the developing countries like Bangladesh, it is the rural areas that face the greatest threat from indoor pollution, where people continue to rely on traditional fuels such as firewood, charcoal, and cowdung for cooking and heating. Concentration ofindoor pollutants in household that burn traditional fuels are alarming. Burning such fuels produces large amount of smoke and other air pollutants in the confined space of the home, resulting in high exposure. Women and children are the groups most vulnerable as they spend more time indoors and are exposed to the smoke. In 1992, the world bank designated indoor air pollution in the developing countries as one of the four most critical global environmental problems. Daily averages of pollutant level emitted indoors often exceed current WHO guidelines and acceptable levels. Although many hundreds of separate chemical agents have been identified in the smoke from bio-fuels, the four most serious pollutants are particulates, carbon monoxide, polycyclicc organic matter, and formaldehyde. Unfotunately, little monitoring has been done in rural and poor urban indoor environments in a manner that is statistically rigorous.

In urban areas, exposure to indoor air pollution has increased due to a variety of reasons, including the construction of more tightly sealed buildings, reduced ventilation, the use of synthetic materials for building and furnishing and the use of chemical products and the use of household care products. Indoor air pollution can begin with the building or be drawn in from outdoors.

Other than nitrogen dioxide, carbon monoxide and lead, there are a number of other pollutants that affect the air quality in an enclosed space. One of the most harmful indoor air pollutants is volatile organic compounds originate mainly from solvents and chemicals. The main indoor sources of these compounds are perfumes, hair sprays, furniture polish, glues, air freshners, moth repelents, wood preservatives and many other products in the house. The main health effect is the imitation of eye, nose and throat. In more severe cases, there may be headaches, nausea and loss of coordination. In the long term, some of the pollutants are suspected to damage to the liver and other parts of the body. Another most serious indoor air pollutant is tobacco smoke that generates a wide range of harmful chemicals and is known to cause cancer.

It is well known that, passive smoking causes a wide range of problems to the passive smoker (the person who is in the same room with a smoker and is not himself a smoker) ranging from burning eyes, nose, and throat irritation to cancer, bronchitis, severe asthms and a decrease in lung function. Biological pollutants include pollen from plants, mite, hair from pets, fungi, parasites and some bacteria. Most of them are allergens and can cause asthma, hay fever and other allergic diseases. The chemical that causes most people difficulty is Formaldehyde, a gas that comes mainly from carpets, particles boards and insulation foam. It causes dizziness, irritation to the eyes and nose, and may cause allergies in some people. Radon gas is another harmfun pollutant that is emitted naturally by the soil. Due to modern houses having poor ventilation, it is confined inside the house causing harm to the dwellers.

Sick building syndrome occurs when several people are affected, but no specific source of the illness is found. Indoor air quality problems usually only cause discomfort, and most people feel better as soon as they eliminate the source of the pollution. However, some pollutants can cause diseases that show up much later, such as respiratory diseases or cancer. In order to prevent indoor air pollution some necessary stepes should be taken such as- to ban smoking or limit it to well ventilated areas, to install efficint chimneys for wood burning stoves, to increase intake of outside air, to use adjustable fresh-air vents for work places, circulate building's air through rooftop, to change indoor air more frequently, to use less polluting substitutes for harmful cleaning agents, paints and other productsetc. In private homes it is better to avoid carpets, furnishing fabrics, wallpapers etc.

Human beings spend approximately 80% of their time indoors; thus the degree of contamination of the indoor air is of considerable concern as well. So, it is important to make sure that our buildings are well-ventilated and eliminating pollutants can improve the quality of our indoor air.