Let indoor air science catch up to policy.

A recent California legal case involving indoor air quality (IAQ) is reverberating in offices, schools and other public buildings throughout the nation.

In Call vs. Prudential - five years in litigation and settled out of court for an undisclosed sum - the plaintiffs charged that the polluted air in the office building where they worked made them ill. Pretrial hearings and arguments revealed that the building's architects and contractors hadn't given any thought to IAQ in designing its ventilating system. But the judge ruled that they could be held liable if the jury decided the system was defective.

This legal scenario could have been played out, to nearly the last detail, in any city in the country. Thousands of buildings have ventilation systems much like the one at issue in the California case. Because IAQ science is so far behind IAQ as an environmental issue, the pressure is building in legislatures to do something - anything - about it.

Just what is conclusively known about the ways poor indoor air quality may relate to health problems?

Very little. The science is embryonic. In the years since Legionnaires disease killed 29 members of the American Legion at their annual meeting in Philadelphia 15 years ago, it has been learned that certain biological contaminants of indoor air - molds, fungi, bacteria and dust mites - can produce symptoms in some individuals, and that poor air circulation, odors and tobacco smoke can trigger a variety of symptoms and complaints.

The trouble is, the relationship between poor IAQ and the causes of these symptoms is conjectural and clouded by many unknowns. For example, complaints commonly blamed on poor indoor air tend to be non-specific; they could have hundreds of causes. It is also generally true that each individual has his or her own, unique symptoms, which runs contrary to the accepted medical principal that diseases with a common cause are generally similar in character. Moreover, investigations of air quality find no uniformly consistent characteristics of indoor air quality regularly linked to complaints.

Not only is the science on IAQ young, it is often flawed as well. Many studies that have focused only on potential chemical causes are undertaken in response to complaints in which the workers themselves have already reached a conclusion about a cause ("reporter bias"). In others, the researchers may seek only a chemical explanation for symptoms ("observer bias"). Symptom questionnaires are inherently and significantly unreliable.

At this point, the scientific unknowns vastly outnumber the knowns. Critical unanswered questions include: What levels of chemicals (below significant elevations) are associated with what symptoms, if any? How extensively do such emotional factors as job and life stresses contribute to workplace complaints? How can IAQ complaints be due to chemicals whose levels in offices are hundreds of times lower than those set by the Occupational Health and Safety Administration based on considerable research concerning workplace exposures? How have popular perceptions of IAQ problems or of chemical hazards influenced the growth of indoor air complaints?

Ronald E. Gots, M.D., Ph.D. is chairman of the Science Advisory Board of the National Environmental Development Association's Total Indoor Environmental Quality coalition (NEDA/TIEQ). Dr. Gots was a featured speaker at an indoor air quality symposium for Los Angeles business leaders sponsored by the NEDA/TIEQ coalition earlier this year. His new book, Toxic Risks: Science, Regulation and Perception makes the case for regulation based on complete and sound science.