Dear EarthTalk: What is "sick building syndrome?".

--Annie Sundberg, New York, NY

The term "sick building syndrome" was coined in the 1970s to describe a phenomenon whereby occupants of a building would become ill without explanation, and then symptoms would appear to decrease or go away altogether once they left the building.

According to the U.S. Environmental Protection Agency (EPA), those afflicted usually experience symptoms such as headaches; eye, nose or throat irritation; dry cough; dry or itchy skin; dizziness and nausea; difficulty concentrating; fatigue; and extra sensitivity to odors. Usually sick building syndrome is associated with commercial buildings, but residential homes can also trigger symptoms. And, according to the U.S. Green Building Council, more than half of all U.S. schools have sick building syndrome.

Ironically, improvements in building design and energy efficiency may be major contributors to the problem, as airtight indoor space is not as well ventilated as areas cleansed by fresh air breezes. According to the National Institute for Occupational Safety and Health indoor air pollution, biological contaminants such as bacteria and mold and inadequate ventilation have all contributed to a rise in SBS in recent years.

Adhesives, upholstery, carpeting, copiers, manufactured wood products, cleaning agents and pesticides are all sources of indoor air pollution, as are many of the chemical smells and other odors present in manufacturing and service settings. Also, according to the EPA, outdoor pollutants such as car exhaust can enter buildings through poorly located air intake vents and windows and become trapped indoors.

It's no wonder that cases of sick building syndrome have been on the rise in recent years: People are spending more and more time indoors, and building materials, furniture and equipment contain many more synthetic chemicals than they did 50 years ago. Buildings operated or maintained in ways they were not originally designed for can create problems, as can occupant activities such as smoking or the use of colognes and perfumes.

Not everyone is convinced that on-the-job illnesses are associated with a building's environmental factors. In a study conducted by Dr. Mai Stafford, M.D. of the University College London Medical School, symptoms were instead strongly linked to other factors such as job stress and lacking social support at work. Dr. Stafford and colleagues concluded, "...if sick building syndrome is reported in a building, management should consider causes beyond the physical design and operation of the workplace and should widen their investigation to include the organization of work roles and the autonomy of the workforce."

A combination of measures can help reduce sick building syndrome, including increasing ventilation and air distribution, removing known pollutants, replacing water-stained ceiling tiles and carpets, introducing air filtration-and educating management and maintenance personnel. Heating, ventilation and air conditioning systems, at a minimum, should meet local building code ventilation standards. And time should always be allowed for new building materials to off-gas chemical contaminants before occupancy.

CONTACTS: EPA Sick Building Syndrome page, www.epa.gov/iaq/pubs/sbs.html.