You can get a new pollen filter. Old one is underneath the glovebox. There's a guide somewhere but on iPhone. Replace the filter and run an aircon Cleaner TBH I did the above two - filter didn't make any difference as it had been recently replaced. Aircon cleaner lastes 2-3 weeks max. At the mo, I turn off the aircon and let fresh air blast through the vents in the last few minutes of a drive.