Dry-Air Health Effects
An indoor relative humidity (RH) less than 30% causes
dry-air problems: excess of static electricity, skin irritation,
respiratory problems, and problems in timber walls and floors,
cracks in drywall or problems involving furniture.
Humidifiers: Recommendations for Use and Care
Humidifiers should be used with some care. Though they can solve
health problems caused by dry-air, in some particular cases they
may be also responsible for negative health side effects.
There are some
reports pointing to negative
health effects resulting from the dispersal of
microorganisms and minerals by home humidifiers - though these
problems are mainly restricted to particular types of
humidifiers: ultrasonic and impeller humidifiers...
It is important
to use a humidifier only when conditions require it, to use
the correct moisture setting for existing conditions, and to
clean it thoroughly.