Natural ventilation turns the air over more efficiently than mechanical air freshening systems, reducing risk of TB transmission.
Contrary to popular wisdom, a new study finds that if you want to avoid getting sick you should open a window. At least if you don’t want to catch TB in a hospital in Lima, Peru. Researchers from the Imperial College London were looking for ways to limit the spread of tuberculosis in the Peruvian situation. One major site of transmission is apparently the hospital waiting room, where infected individuals come to be treated. In close quarters, one person with TB can infect many others, by sneezing, coughing, even speaking. To curb the contagion, the researchers prescribed ventilation. And the best ventilation, they find, is the simplest—opening the doors and windows. Such natural ventilation really keeps things moving, allowing the air in the room to be replaced by fresh air an average of 28 times an hour. Even mechanical systems specifically designed to exchange the air in isolation wards only achieve 12 air changes an hour, and that’s when they’re working at maximum capacity, which is not often the case. The study is good news for hospitals that can’t afford sophisticated mechanical ventilation systems. And it’s a real shot in the arm for people who’ve always said that a little fresh air is good for you.