I understand how fixing leakages, or more generally, not properly ventilating your place, would increase CO₂ levels, but where do air purifiers come into the pi

I understand how fixing leakages, or more generally, not properly ventilating your place, would increase CO₂ levels, but where do air purifiers come into the picture? Is it just because someone who has an air purifier is also more likely to not ventilate (to keep PM2.5 down?), or are air purifiers themselves somehow bad for CO₂ levels? I can't guess why they would be, and searching around a bit doesn't seem to suggest that's the case either.