Weed smell in baby’s room

I imagine this question has been asked a million times and when trying to search around, I see a million answers.

Our 4 month old’s bedroom is the only room in the house that gets the smell of weed coming through what I assume are the walls as I don’t smell it coming from the vents.

Is there an air purifier that I can buy that would eliminate this smell? I can’t have my baby sleeping in there when it smells like that.

Thank you in advance for any information anyone can provide. I’m not really sure what to do.