I find so much relief with my sinuses when I have this on. I have absolutely noticed that the color sensors work great too. When the air is clean the purifier will let you know by illuminating a white light. When the air is really “dirty” the light illuminates red, and when it is in between air quality it lights up orange. I’ve tested it by burning incense (which I have recently stopped using because of worsening sinus issues) and the purifier lights red. It does work to eventually clean out the air. As it does work to clean out the air from distant fires during the west coast fire season. It’s amazing how it knows but it knows. It works great!