Drying your hands with paper towel will reduce the bacteria count by 45 – 60% on your hands. However, using a hand dryer will increase the bacteria on your hands by up to 255% because it blows out bacteria already living in the, conveniently, warm moist environment
“Last time, I talked about handwashing hygiene, when you’re away from
home and using public conveniences, which includes the act of actually
drying your hands. This drying should not just remove water. It should
also remove bacteria.
Now there are different ways of drying your hands: paper towels, continuous-loop cotton towels and warm-air dryers.
Researchers got a real surprise when they counted the bacteria left on the fingertips after using these drying methods.
Washing the hands, and then using paper towels or continuous-loop
cotton towels reduced the bacterial count by about 45–60 per cent. But
washing, and then using a warm-air dryer actually increased the
bacterial count by an average of 255 per cent.
How could drying your hands increase the number of bacteria on your skin?
When they went looking further, the researchers found out how.
The bacteria were already inside the warm-air dryers, thanks to the warm
moist environment. Every single warm-air dryer they tested had high
bacterial counts on the air inlet, while 97 per cent had them on the
outlet nozzle surfaces as well.
These were the figures for warm-air blower in public toilets. Of
course, if you choose to do your measurements in a clean laboratory,
you’ll find lower bacterial counts.
Just imagine warm air blowing over poorly washed moist
bacteria-laden fingers in a grimy public toilet. It’s an ideal way to
spread bacteria and other germs through the air, in an aerosol of tiny
But in most cases it doesn’t matter, because our immune systems
are resilient enough to keep the numbers of these bacteria low.
Furthermore, the overwhelming majority of these bugs are fairly
harmless. They don’t usually include the real nasties like salmonella,
shigella, campylobacter, hepatitis A or B, the SARS coronavirus, or the
virus that causes meningococcal disease.
Now one important reason that you want to dry your hands is to
remove the bacteria that are floating in the thin layer of water. After
all, if you just let your hands dry slowly in the air, the bacteria will
still be sitting on your skin.
With a towel (paper or cloth) you can apply some decent
mechanical friction to your hands. This is an important part of the