I have been purchasing 3M (Allergen + Odor Reduction) filters every since I wound up going to the emergency room for severe Asthma attacks (Twice).  I do believe you would find the cost of the filter much less than a visit to the emergency room + a two day stay in the hospital.  I can assure you that it is much less painful both to the ole bod and the wallet.  The filter is simply OUTSTANDING and helps keep me out of the hospital.  I fully recommend this filter, it truly performs as advertised.