This is more microbiology than chemistry but it has been a subject that fascinated me. Electric hand dryers in public toilets have long been touted as more hygienic than paper towel.
Not so, it seems.
[Wikipedia] In 2008, a study was conducted by the University of Westminster, London, to compare the levels of hygiene offered by paper towels, warm air hand dryers and the more modern jet-air hand dryers .
The key findings were:
- after washing and drying hands with the warm air dryer, the total number of bacteria was found to increase on average on the finger pads by 194% and on the palms by 254%
- drying with the jet air dryer resulted in an increase on average of the total number of bacteria on the finger pads by 42% and on the palms by 15%
- after washing and drying hands with a paper towel, the total number of bacteria was reduced on average on the finger pads by up to 76% and on the palms by up to 77%.
The scientists also carried out tests to establish whether there was the potential for cross contamination of other washroom users and the washroom environment as a result of each type of drying method. They found that:
- the jet air dryer, which blows air out of the unit at claimed speeds of 400 mph, was capable of blowing micro-organisms from the hands and the unit and potentially contaminating other washroom users and the washroom environment up to 2 metres away
- use of a warm air hand dryer spread micro-organisms up to 0.25 metres from the dryer
- paper towels showed no significant spread of micro-organisms.
...
Ah, but consider this - most men don't wash their hands in the first place. Place something like a Dyson Airblade in a public loo and you can almost guarantee that all of them will be so intrigued by the technology that they will actually wash their hands.
ReplyDeleteBy the way, I thought urine was sterile anyway and most people use paper when wiping their bums. Theoretically there should be no bacteria, except those you come into the loo with in the first place.
ReplyDeleteSpeaking of blow-jobs,I take Bill's point. Could you imagine that other Bill saying to Monica "Shouldn't you wash that before you put it in your mouth?"
ReplyDeleteBehave yourself, Cosmo!
ReplyDeleteMind you, there is something in what you say. We have been conditioned to the hand washing thing.
Chairman Bill....ick! I absolutely do not believe that most men don't wash their hands. But about the paper towel vs. the blowers...very enlightening. Thank you. I'm passing the word.
ReplyDelete