They claim the problem with de-humidifiers is that although they can lower
the r.h., they recirculate the air containing allergens, and can actually
fragment the mite droppings and cause the allergens to remain airborne for
longer.
Each little mite produces about 20 dung pellets a day, which contain the
allergens.
Some of the research mentioned also backs up thew link between the house dust
mite and asthma mentioned by others in this debate. ( Incidence of asthma
rose by 700% over eight years in Papua New Guinea after blankets were
introduced to the native population.) Anyone know if this is now a generally
established connection?
The UK building services bible (CIBSE Guide) recommends r.h. should not be
less than 40% for general applications. Apart from dry throats and the like,
electrostatic shocks, which tend to depend on the electrical resistance of
floor coverings, set in at below 40% r.h. What do ASHRAE recommend?
Matthew Hill, Leeds Environmental Design Associates
__________________________________________________________________
This greenbuilding dialogue is sponsored by Oikos (www.oikos.com)
and Environmental Building News (www.ebuild.com). For instructions
send e-mail to greenbuilding-request@crest.org.
__________________________________________________________________