Clean Air Delivery Rate - AHAM Certified From air cleaner to air cleaner, compare the CADH numbers. First, look at suggested room size. Then refer to the tobacco smoke, dust and pollen Clean Air Delivery Rate numbers. The higher the numbers, the faster the unit filters the air. This air cleaner is suggested for use in a single closed room up to 240 square feet. Room size ratings conform to the AHAM Certification Program criteria of 80% smoke reductions. Higher Clean Air Delivery Rates provide improved performance in all room sizes. Portable air cleaners will be much more effective in rooms where all doors and windows are closed. Tobacco Smoke: 155 Dust: 145 Pollen: 155 Association of Home Appliance Manufacturers Hunter Model 30771 ; Questions?