What's the link? A poor ventilation system that does little more than recycle old, stale air from one end of the building to another.; Millions of American office workers are getting more than they bargained for when they inhale in a building that has no fresh air. Along with oxygen, they may be getting flu and other infectious bugs from their co-workers.; That's because, in today's modern office buildings, recirculated air can mean recycled flu and other airborne infections. The evidence comes from various studies of tuberculosis, measles and flu that spread in a manner that can only be explained by poor air ventilation.; "Modern office buildings are tight," says Jon Rosenberg, public health officer in California's occupational health program. "In order to conserve energy, they're often sealed."; Experts say the problem is not the same as "sick building syndrome" -- a situation in which workers are exposed chronically to toxic chemicals and gases emitted from carpets, furniture and other building materials. Nor is it to blame for last month's outbreak in Richmond of Legionnaire's disease -- an illness caused by a bug linked to wet, damp spaces rather than poor ventilation.; But as in "sick building syndrome," it's the airtight environment that sets the stage for problems. Lack of windows is not necessarily the culprit. "If it has a good ventilation system . . . you don't necessarily have to have a sick building," Rosenberg says.; But, alas, many modern ventilation systems recirculate indoor air with little or no fresh air. So the infectious bugs that a worker exhales at one end of the building can end up, via the ventilation system, being inhaled at the other end.; "The building is not the source. People are the source," says Dr. Edward Nardell, who studies airborne infections for the Massachusetts Department of Public Health. "Very bad ventilation makes the system worse."; In a study published in the August issue of the American Review of Respiratory Diseases, Nardell and colleagues at Harvard Medical School found that an outbreak of tuberculosis documented in one unidentified government building could have been cut in half had the ventilation been better.; The study found that 40 percent of the building's workers -- or 27 of 47 -- were infected with tuberculosis from one 30-year-old sick employee. The infection rate was as high in some distant parts of the building as it was next to the sick employee.; "By recirculating the air, you spread it throughout the building," says Nardell. "People who had no direct contact with this case, might have been exposed in far reaches of the building."; If tuberculosis can spread in poorly ventilated buildings, so can other infectious bugs. Respiratory infection experts say that flu viruses and measles are easier to spread than TB.; "This particular study deals only with TB," says Dr. Jonathan Samet, a respiratory-disease expert at the University of New Mexico, "but the observations may apply to other organisms, such as the respiratory viruses that cause flu."; Building workers had complained for years about poor air quality.; The building's ventilation system permitted circulation of some outdoor air -- 15 cubic feet per minute -- a low level commonly found in buildings since the 1930s. Even lower levels of outdoor air ventilation, below 10 cfm, have become common since 1973, the post-oil embargo era.; In the study, Nardell estimated that if outdoor air ventilation in the government building had been doubled -- to about 35 cubic feet per minute, a level that Massachusetts recommends for buildings where smoking is permitted -- only half as many workers would have been infected with tuberculosis.; Other studies have documented:; (check) Flu spreads quickly on airplanes where ventilation systems consist entirely of recirculated air.; (check) Measles are transmitted by infectious air in a pediatrician's waiting room.; (check) Tuberculosis can spread in homeless shelters, prisons and hospitals where ventilation is poor.; Flu spreads much more easily than TB. "It may survive several hours in dry air," says Vernon Knight, a respiratory virus disease expert at Baylor College of Medicine in Houston. "In those tight buildings, they continue to recirculate it, and they probably build up."; Nardell and others recognize that the solution to this problem -- fixing or replacing ventilation systems to include more fresh air -- can be expensive. Flu and colds will probably never be eliminated from the workplace entirely, and it may not make sense to install a new ventilation system unless the air quality is very low.; In his tuberculosis study, he found that the biggest benefit comes from improving the worst ventilation systems that allow very little fresh air. If the ventilation is moderately effective but not ideal, further improvements yield only a slight decrease in infectious illness.; "There's only so much you can do," Nardell says. "There's going to be a price of living together in a communal society."; YOU'RE INTERESTEDEmployees who think that poor air quality at their workplace is contributing to health problems can call Cal-OSHA, a state agency that monitors worker safety and health. In San Jose, Cal-OSHA can be reached at (408) 452-7288.
A study covering the outbreak of tuberculosis in an unidentified government building found that the number infected could have been cut in 27 with better ventilation. Forty- seven workers in the building, and half of them contacted tuberculosis, but many of the half did not work in close proximity to the infected carrier. New office buildings, built with an eye to lower heating and cooling costs, are sleek and airtight. Stale air is recirculated with not enough intake of fresh air, and such can be a factor in the spread of tuberculosis. Poor ventilation is often present in homeless shelter, prisons and hospitals.