Dear Jane, or is it Dale? (see 1/17/98 posting) Since you both have the same e-mail address I don't know who I'm talking to. "Dale" was kind enough to post some numbers for types of paticulate removal, but again, to what recognised standard are these filters tested? If you don't test to ASHRE 58.1-1992, then what? Numbers are meaningless unless it is known how they are derived. Why should any one fork out $44 on the strength of a questionable testimonials, and unsubstantiated statements and numbers? With all due respect, put up or shut up!