The term "sick building syndrome" (SBS) is used to describe situations in which building occupants experience acute health and comfort effects that appear to be linked to time spent in a building, but no specific illness or cause can be identified. The complaints may be localized in a particular room or zone, or may be widespread throughout the building. In contrast, the term "building related illness" (BRI) is used when symptoms of diagnosable illness are identified and can be attributed directly to airborne building contaminants.
A World Health Organization Committee report suggested that up to 30 percent of new and remodeled buildings worldwide may be the subject of excessive complaints related to Indoor air quality (IAQ). Often this condition is temporary, but some buildings have long-term problems. Frequently, problems result when a building is operated or maintained in a manner that is inconsistent with its original design or prescribed operating procedures. Sometimes indoor air problems are a result of poor building design or occupant activities.
Indicators of SBS include :
• Building occupants complain of symptoms associated with acute discomfort, e.g., headache; eye, nose, or throat irritation; dry cough; dry or itchy skin; dizziness and nausea; difficulty in concentrating; fatigue; and sensitivity to odors.
• The cause of the symptoms is not known.
• Most of the complainants report relief soon after leaving the building.
Indicators of BRI include :
• Building occupants complain of symptoms such as cough; chest tightness; fever, chills; and muscle aches.
• The symptoms can be clinically defined and have clearly identifiable causes.
• Complainants may require prolonged recovery times after leaving the building.
What are the Sources of Pollution?
There are four broad categories of contributors to "sick building syndrome."
Biological contaminants include bacteria, molds, mildew, viruses, animal dander and cat saliva, house dust mites, cockroaches, and pollen. There are many sources of these pollutants. Pollens originate from plants; viruses are transmitted by people and animals; bacteria are carried by people, animals, and soil and plant debris; and household pets are sources of saliva and animal dander. The protein in urine from rats and mice is a potent allergen. When it dries, it can become airborne. Contaminated central air handling systems can become breeding grounds for mold, mildew, and other sources of biological contaminants and can then distribute these contaminants through the home.
Inadequate ventilation :
In the early and mid 1900's, building ventilation standards called for approximately 15 cubic feet per minute (cfm) of outside air for each building occupant, primarily to dilute and remove body odors. As a result of the 1973 oil embargo, however, national energy conservation measures called for a reduction in the amount of outdoor air provided for ventilation to 5cfm per occupant. In many cases these reduced outdoor air ventilation rates were found to be inadequate to maintain the health and comfort of building occupants. In an effort to achieve acceptable IAQ, ventilation standard should be a minimum of 15 cfm of outdoor air per person (20 cfm/person in office spaces). Up to 60 cfm/person may be required in some spaces (such as smoking lounges) depending on the activities that normally occur in that space.
What are the typical symptoms Of SBS?
• unusual fatigue
• varying degrees of itching or burning eyes
• skin irritation
• nasal congestion
• dry or irritated throats, and;
Specific Illnesses :
• Indoor transmission of standard infectious diseases such as tuberculosis or legionellosis.
• Allergic reactions to indoor allergens such as dust mites, plant products, or fungal products.
• Irritation due to (volatile) chemicals released from the environment.
• Carbon monoxide poisoning related to recirculation of cigarette smoke or exhaust fumes.
Non-Specific Illnesses :
• This is a diverse group of work-related symptoms that include irritation of the skin, mucous membanes (mouth, nose, throat), headache, fatigue, and difficulty concentrating.
• A variety of factors have been associated with increased rates of these complaints :cigarette smoking, type of work (e.g., working near a photocopier), level of office crowding, presence of carpets, and type/volume of ventilation.
Solutions to Sick Building Syndrome :
Solutions to sick building syndrome usually include combinations of the following :
Pollutant source removal or modification :
is an effective approach to resolving an IAQ problem when sources are known and control is feasible. replacement of water-stained ceiling tile and carpeting; institution of smoking restrictions; venting contaminant source emissions to the outdoors; storage and use of paints, adhesives, solvents, and pesticides in well ventilated areas, and use of these pollutant sources during periods of non-occupancy; and allowing time for building materials in new or remodeled areas to off-gas pollutants before occupancy. Several of these options may be exercised at one time.
Increasing ventilation rates :
and air distribution often can be a cost effective means of reducing indoor pollutant levels. When there are strong pollutant sources, local exhaust ventilation may be appropriate to exhaust contaminated air directly from the building. Local exhaust ventilation is particularly recommended to remove pollutants that accumulate in specific areas such as rest rooms, copy rooms, and printing facilities.
Air cleaning :
can be the most important aspect in removal of SBS. Pollutant source removal or increasing ventilation rates may not be possible at many times. Hence removal of particles (particles are the carriers of micro-organisms) & gaseous elements from the air with an efficient air filtration device can be the most cost effective & convenient solution.