Hand dryer spreads bacteria around
DEAR DOCTOR: Considering the recent news coverage of how hot-air hand dryers do little more than blow bacteria around, am I better off just wiping my hands on my pants when using a public restroom?
DEAR READER: This would have seemed a ridiculous question only two decades ago — before bathroom hand dryers had proliferated throughout the developed world. The use of paper towels in bathrooms had created concerns about environmental impact, both in connection to the trees used to make the paper towels and in the amount of trash produced. Bathroom hand dryers, although they used energy, decreased the use of, and trash from, paper towels — not to mention they were (and remain) — very cost-effective. The operation of bathroom hand dryers is only one-tenth to one-twentieth the cost of a year’s worth of paper towels.
But, yes, now there are concerns about bathroom hand dryers and hygiene. In short, air hand dryers can aerosolize bacteria. A recent study at the University of Connecticut School of Medicine evaluated whether hand
dryers contaminated the area around them with bacteria. In their tests, the bacteria appeared not to come from the hand dryer itself, but from bacteria in the bathroom that was sucked into the air coming out of the fan.
Two interesting notes: First, researchers saw no difference between women’s and men’s restrooms. Second, placing a HEPA filter within the hand dryer led to a fourfold reduction in the number of bacteria seen on the growth plates used in the study.
But because the hand dryers disperse bacteria does not necessarily mean they will increase the risk of infections, at least for most people. Those who have compromised immune systems, disruptions of the skin or intravenous lines, however, could potentially develop invasive infections.
A better study would be comparing the bacteria upon the hands of people who used either hand dryers or paper towels.
Until then, it’s better to use paper towels until hand dryers with bacteria-reducing HEPA filters become widely available.