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From: henry@utzoo.UUCP (Henry Spencer)
Newsgroups: sci.electronics
Subject: Re: Ultrasonic humidifiers
Message-ID: <7674@utzoo.UUCP>
Date: Thu, 19-Feb-87 20:54:42 EST
Article-I.D.: utzoo.7674
Posted: Thu Feb 19 20:54:42 1987
Date-Received: Thu, 19-Feb-87 20:54:42 EST
References: <15214@onfcanim.UUCP>, <555@pixar.UUCP>
Organization: U of Toronto Zoology
Lines: 19

> Unlike the old steam vaporizers, they don't boil the water - so whatever
> is growing in that water just gets thrown into the air, and eventually
> winds up in your lungs.

Most household humidifiers are not steam vaporizers, if for no other reason
than because boiling water is expensive in energy.  They generally rely on
room-temperature evaporation.

> I don't know how effective high-frequency sound is at killing bacteria,
> and how much of the atomized water has been subjected to the high-amplitude
> vibration.

I seem to recall that Consumer Reports looked at this and concluded that
the bacteria count coming out of an ultrasonic humidifier was significantly
less than that from ordinary humidifiers.  The ultrasound seems to kill the
beasties moderately well, although not perfectly.
-- 
Legalize			Henry Spencer @ U of Toronto Zoology
freedom!			{allegra,ihnp4,decvax,pyramid}!utzoo!henry