The response, says Dr. Dick Menzies, has been “unbelievable.” Everyone, it seems, has a sick building they’d like to heal. E-mails from as far away as China and India, and from engineers and architects to ordinary office workers, have jammed Menzies’ in-box at the Montreal Chest Institute, part of McGill University. That’s because Menzies, a respirologist, and his colleagues demonstrated that ultraviolet light kills mould and bacteria in air-conditioning systems and can improve the health of workers. “Nobody wants another legionnaires kind of outbreak,” says Menzies, “This technology can prevent that.” Researchers have long known mould and bacteria thrive in the dark, moist confines that house air-conditioning equipment. Studies have also linked cooling systems to sick buildings in which people complain of headaches, fatigue, difficulty concentrating, skin rashes and congestion.
So Menzies’ team examined four Montreal office towers, fitting the air-conditioning systems with UV lamps to bathe the drip pans and cooling coils in germicidal light for a month. (UV light is already used to sterilize the air in operating rooms and pharmaceutical facilities.) Researchers also turned the UV lamps off for three months to allow mould and bacteria to grow back. They repeated the cycle two more times over the course of nearly a year.
Researchers didn’t tell the study’s 771 respondents when the germ-killing lights were on. The result: workers reported a 20-percent reduction in ailments with the UV working, and a 40-per-cent drop in respiratory problems. Non-smokers and those with allergies seemed to experience the greatest benefits. Menzies says it costs about $65,000 to install the UV hardware in a typical office building with 1,000 employees, and would likely reduce days lost to illness. “That’s pretty cheap,” he adds. It also sounds like a breath of fresh air.
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