Air purifiers should be chosen by evaluating clean air delivery rate and room coverage to ensure proper air circulation rather than relying solely on advertised room size.
Key terminology includes CADR for cleaning volume, HEPA filters for capturing fine particulate matter like PM2.5, and ACH for air changes per hour.
Buyers must account for filter replacement costs and availability, activated carbon filters for odour reduction, and built-in PM2.5 sensors for automated fan adjustment.