Which is safer and most effective for removing pet odors….an ionizer or a HEPA air purifier?

I live close to a paper mill and have pets…so when I try to air my home out to get rid of pet odor smells….I get yucky smelling paper mill smells mixed with the existing pet odors. I’m hoping to find an air purifier that works and will greatly reduce the odors in my home since it seems I can’t get fresh air in through my windows!