I was just visiting Louisiana and discovered that locations below sea level have serious problems with mold...I visited a museum that made my throat constrict within twenty minutes. After about 45 minutes, my companion's head was spinning with the effects of the mold, so we got out, but it was too late. I've now got another in a long sad history of sinus infections which means I can't sing at all and probably won't be able to for another two or three weeks. This won't do, so I've decided a good investment for the New Year will be an air purifier for my apartment (won't help with musty museums, but it's a start anyway). So of the HEPA filter types (Honeywell Envirocaire, Holmes, etc.), does anyone here have a recommendation regarding the noise level of the various choices? Seems like most of them function at about the same level of particle absorption, but I'd really love a very quiet one. Thanks. Margaret