When your air isn't as fresh as it could be, you want to invest in a carbon pre-filter. Not only will it filter out the larger bits from the air and extend the life of your primary filter. It also has carbon that will fix and remove volatile chemicals from the air that make your stinky air so memorable. You do need to change them more often. Swap out your prefilters every four to six weeks and your primary filter every four to six months for maximum efficiency.
Please note the following important information about this product from Think Crucial: (i) it is a generic replacement, NOT a Whirlpool® Original Equipment Manufacturer (OEM) product; (ii) because it is not a Whirlpool® OEM product, it is not covered by any Whirlpool® guarantee or warranty; (iii) use of this generic replacement may violate or void Whirlpool's® guarantee or warranty - it is entirely your responsibility to check, and entirely your risk if you decide to use this product; (iv) we do not guarantee or warrant that this generic replacement is compatible with any product from Whirlpool® or any other provider. Please check your manufacturer's warranty with regard to the use of non-OEM parts. Think Crucial provides no warranty or guarantee with regard to the product or its compatibility with your Whirlpool® product. The Whirlpool® brand and all Whirlpool® trademarks belong to Whirlpool® or its affiliates, and are used here only to explain the compatibility features of the generic replacement product.