are you shure they do not come with them. every other car ive had they have been below the window wpiers. lift the bonnet and right at the top. pull off the rubber strip and then pull up the plastic cover and ur filter will be there.
there must be a pollon filter so you dont get leaves and dust and crap being sucked in and blown into the car through the vents.
ive had 4 cars only 1 with air-con and every one has had a polen filter.