Great air cleaner. We were in the middle of wildfire smoke here n Oregon. The air quality index for our area was 475, which is very hazardous. When we turned on our bissel air400 air purifier the air quality in our house was 278; which is very unhealthy. Within 3 days the air quality in our house was under 30, which is healthy. We have had our air purifier for 2 weeks and the air quality in our home is now at 2. What a difference. Thanks Bissell!