In recent years people who live and work indoors have reported many symptoms of physical discomfort such as fatigue, headaches, sore throat, nausea and eye irritation. Such symptoms have appeared most frequently in conditioned buildings where very little ventilation is present.

This has led to the phrase 'Sick Building syndrome'(SBS). The term "Sick Building Syndrome" first employed in the 1970s, describes a situation in which reported symptoms among a population of building occupants can be temporarily associated with their presence in that building. If 20% of the occupants complain about the same symptoms, and the absence of those symptoms when they leave the building then the 'Sick Building Syndrome' should be suspected.

Causes of 'SBS' may lie in one or more of the following reasons:

The ventilation/air-conditioning system is often the major problem either because it is not achieving an appropriate air exchange rate or the system is a source of contamination.

Mechanical air-conditioning systems in buildings are designed and operated not only for cooling the air but also to draw in and circulate outdoor air, ventilation allows for exchange of air between the indoors and the outdoors. It is this circulation of air which prevents indoor air pollution.

The cheapest method of maintaining air exchange is to keep doors and windows open throughout the day. Problems arise when, in an effort to save energy, air-conditioning systems are not being used to bring in adequate amounts of outdoor air.

Inadequate venalities also occurs if the air supply and return vents within each room are blocked or placed in such a way that outside air does not actually reach the breathing one of building occupants. The stale contaminated air is recirculated again and again giving rise to pollutant levels dangerous to health. Improperly located outside air intake air vents an also bring in air contaminated with automobile and truck exhausts, boiler emissions or air vented from rest rooms.

Finally, inadequate maintenance of the HVAC system can be a source of indoor air pollution by spreading biological contaminants that have multiplied in cooling towers, air conditioners, or the inside surfaces of ventilation ductwork. High humidity may also be a factor contributing to biological pollutant problems, mold and fungi growth.

Though the phrase 'Sick building Syndrome' may be new or unknown to us, however, the associated problems are not unknown. The pollutants outlined above when present even in low levels indoors act synergistically or in combination to cause health effects.

Historical Perspective of Poor IAQ The origins of the poor IAQ can be traced back to the oil embargo of the 1970's which transformed concerns over energy availability into a belief that the world was in an energy crisis. Energy had to be conserved at any cost, regardless of the consequences. The result was that the buildings were built to conserve energy by keeping 'outdoor air out' and 'indoor air in' Inadequate ventilation led to poor Indoor Air Quality.

IAQ and Health

It has been established beyond doubt that poor IAQ does affect our health. Health effects from indoor air pollutants fall into two categories: those that are experienced immediately after exposure and those that do not show up until later years.

Immediate effects which may show up after a single exposure or repeated exposures, include irritation of the eyes, nose and throat, headaches, dizziness and fatigue. These immediate effects are usually traceable by eliminating the person's exposure to the source of pollution.

Symptoms of some diseases like asthma, hypersensitivity and pneumonities and even colds can show up soon after the exposure to some indoor air pollutants.

Other health effects may show up either years after exposure has occurred or only after long or repeated periods of exposure.

While pollutants commonly found in indoor air can be responsible for many harmful effects, there is considerable uncertainty about what concentrations or periods of exposure are necessary to produce necessary health effects also people react differently to exposure to indoor air pollutants, depending on age preexisting medical condition and individual sensitivity.

Some common pollutants and their effects on health

ENVIROMENTAL TOBACCO SMOKE (ETS)

Source - ETS is a major indoor air pollutant. It is a combination of side stream smoke (i.e. smoke which comes from the burning end of a cigarette) and smoke exhaled by the smoker. It's a mixture of more than 4,000 chemicals,most of which are toxic.

Health Effects - ETS creates health problems for both smokers and non - smokers alike. This pollutant is the leading cause of lung cancer. It also causes problems like headaches, irritation in the eye, wheezing and continued cough in adults. In children it can cause asthma and bronchitis.

BIOLOGICAL .... BACTERIA, FUNGUS

Source - Our workplaces serve as excellent breeding grounds for biological contaminants like bacteria, mold, mildew, viruses, mites, cockroaches and pollen. Wet or moist walls, ceilings, carpets and furniture, poorly maintained air-conditioners and damp corners are where these contaminants are found.

Health Effects - Some cause allergic reactions, some transmit infectious illnesses (e.g. influenza, measles and chicken pox) and some release toxic chemicals. Symptoms exhibited are eye, nose and throat irritation, shortness of breath, lethargy, fever, digestive problems and asthma. Carbon Monoxide (CO) Source - Carbon Monoxide (CO) is a colourless, odourless gas which can suffocate a person to death. Its source indoors is mainly environmental tobacco smoke.

CARBON MONOXIDE (CO)

Source - Carbon Monoxide (CO) is a colourless, odourless gas which can suffocate a person to death. Its source indoors is mainly environmental tobacco smoke.

Health Effects - At low levels CO causes fatigue as it impairs the distribution of oxygen to the body tissues. In heart patients it causes chest pain. At high levels it results in impaired vision and coordination, headaches, dizziness, confusion, nausea and respiratory irritation. These symptoms disappear with the removal of the source.

Formaldehyde

Source - Formaldehyde is an important chemical used to manufacture building material. Its sources indoors are pressed wood products made by using adhesives, ETS, drapes, other textiles and glues.

Health Effects - Eye, nose and throat irritation, wheezing, coughing, skin rash and severe allergic reactions.

Volatile Organic Compounds (VOCs)

Source - Products like paints, paint strippers and other solvents, wood preservatives, carpets, varnishes and cleaning and disinfecting agents give off organic gases and continue to do so even after a number of years.

Health Effects - Eye, nose and throat irritation, headaches, loss of coordination, nausea, damage to liver, kidney and central nervous system. Some organics are suspected to be carcinogenic.

Asbestos

Source - Asbestos is widely used in fire proofing material, floors and tiles. When asbestos infested material gets damaged or disintegrated, its microscopic fibers are released into the indoor air.

Health Effects - There is no immediate effect of asbestos on human health. The long term effects are chest and abdominal cancer and lung infections. Smokers are at a greater risk of developing asbestos induced lung cancer.