"Lifetime" filter and allergies/asthma

Hello everyone, not really new to the forum but this is my first post.

I've got a 2007 Focus SES 2.0 L (Canada).

I'm not super allergic but dust and feathers are not well received by my respiratory system.

I've noticed that in the last month or so my nose gets pretty runny if I turn on the heating or the ventilation. Seems to be worst with the heating, I don't know why. Does this make sense?

Anyway, I thought it was as easy as replacing the "pollen filter" but no such thing exists on this focus, as I read on several posts here and on the web (my dealer pointed this out too).

So this new "lifetime" filter, what guarantee do I get that it's not dirty or moldy? Something is causing this allergies (my daughter got 2 asthma attacks thanks to this too), is there anything else that could be the reason? Some guy at Canadian Tire suggested a spray to clean the vents, but that doesn't seem too helpful, to be honest.

I've cleaned the car's interior thoroughly and that didn't help.

And one last question:

Can anyone point me to some thread or link where I can see how to remove the passenger panel to remove or at least check out this filter? I'm thinking of replacing it myself if the dealer wants to rip me off to replace it. Even if I do do it with them I'd like to check they actually did change it, since they might try to not do it since they think it's not necessary.

This is a link of a place which seems to sell this filter (not Ford, aftermarket):

http://www.autopartswarehouse.com/s...tk=Main&Ntx=mode+matchallpartial&N=4294965877

I like tweaking and messing up with stuff, from PC's to houses and cars, so don't worry about any warnings. If I mess it up I'll deal with it. ;-)

Thanks in advance for any help.