<p>But some people believe that sudden drops in temperature can play havoc with the immune system. Others say air-conditioners act as germ-spewing machines, cultivating bacteria and viruses like petri dishes and then blasting and recirculating them in enclosed spaces.<br /><br />As with colds and other respiratory ailments contracted in the wintertime, cold air itself is not the culprit — viruses are, said Dr Ujwala Kaza, an allergist and immunologist at New York University Langone Medical Center.<br /><br />Still, researchers at Cardiff University in Wales say it’s possible air-conditioners may contribute in some small way to respiratory infection. They extract moisture from the air, which can dry out the protective mucus that lines the nostrils, allowing viruses a better chance to become established in the nose.<br /><br />One study in 2004 compared 920 adult women and found that those who worked in offices with central air-conditioning had higher rates of absence due to sickness and more visits to ear, nose and throat doctors than those without it. A similar study of almost 800 office workers in 1998 also found more symptoms of sickness in workers in air-conditioned offices, compared with workers in offices with natural ventilation.<br /><br />The verdict<br />There is evidence that air-conditioned environments may contribute to colds, but it’s not definitive.<br /></p>
<p>But some people believe that sudden drops in temperature can play havoc with the immune system. Others say air-conditioners act as germ-spewing machines, cultivating bacteria and viruses like petri dishes and then blasting and recirculating them in enclosed spaces.<br /><br />As with colds and other respiratory ailments contracted in the wintertime, cold air itself is not the culprit — viruses are, said Dr Ujwala Kaza, an allergist and immunologist at New York University Langone Medical Center.<br /><br />Still, researchers at Cardiff University in Wales say it’s possible air-conditioners may contribute in some small way to respiratory infection. They extract moisture from the air, which can dry out the protective mucus that lines the nostrils, allowing viruses a better chance to become established in the nose.<br /><br />One study in 2004 compared 920 adult women and found that those who worked in offices with central air-conditioning had higher rates of absence due to sickness and more visits to ear, nose and throat doctors than those without it. A similar study of almost 800 office workers in 1998 also found more symptoms of sickness in workers in air-conditioned offices, compared with workers in offices with natural ventilation.<br /><br />The verdict<br />There is evidence that air-conditioned environments may contribute to colds, but it’s not definitive.<br /></p>