Munir buying an air purifier isn’t going to fix this problem.
Are you being prompt about cleaning up his messes? Are you being thorough? Dogs are attracted to the spot they urinated last. Unless you are fast and clean the area well, he’ll want to mark that spot again.
It may be better to hire a carpet cleaner or find some pet sprays to help clean it. Nature’s Miracle is sold in most pet stores.
Wish you and your new pup well!