You will find the pollen filter under the wind screen wiper cover on the passenger side. It's often neglected but easy enough to change... follow the step on the link below. Good luck
chhttp://www.puravent.co.uk/filters/display_filter.php?id=168&part=M2189ange.
howtomendit.com for free repair help, information and advice.
Try fixfault.com to fix cars.