To help out the OP:

This "article" is a bit tainted with references to high end products, which may not be necessary, but contains a lot of info on how to locate a filter, replacement etc. I know the filters over here cost around 20 to 30 bucks and are easy to replace by yourself for the X-3.

If your allergies are real bad I guess you would be well off to get in contact with a patients association and ask them for advice(usually there are leaflets at your GPs office or at a local pharmacy - at either location the employees should be able to provide you with information). Asthma may be associated with allergies and you might find help at one of those groups. I could not find a site for an US association. The filter has to be replaced regularly (determine interval suitable for you by inspection and whether you have symptoms or not). Be aware that pollutants are always more concentrated in the cabin compared to the environment. vacuum your car. Good luck.



@stocker: man, we could have many discussions but I'll try to avoid them in the future. At least in someone elses thread :biggrin: