I live in Alaska where we get a lot of tree pollen and. I was very surprised at how quickly my air cleaned when I was cooking bacon. It instantly went red and then within 30 to 40 minutes, completely back to blue no odor left. I also swept the floor in my kitchen and it came back on red and again 20 to 30 minutes the air was back to be completely cleaned and blue. I will recommend these two fellow Alaskans however we do not get free shipping. It is very helpful when they give you a discount and it makes it not so painful for the cost however, I am already finding that it’s going to be worth the purchase.