I purchased (2) Ionic Pro Air Purifiers about 2 1/2 years ago to use in my bedrooms. When I first made the purchase, I thought that the small purifiers was perfect to help eliminate dust and purify the air in my bedroom. After my first cleaning of the purifiers, the motor of one of one of the purifiers begin to keep up noise when I put it on the "Turbo" setting. I had to discontinue use of this purifier because I could not sleep with the noise. Therefore, I started the second purifier purchased in my bedroom. I didn't clean it until several months ago. After cleaning, it also started to keep up noise. I don't think I bent the blades that are very sharp and tedious to clean. The instructions stated that they could be cleaned and that's what I did to remove all of the build-up of dust on the outside. The small purifiers, I would not recommend for purchase because I don't think they were worth the price I paid. Ease of Maintenance Mines became too noisy after cleaning. Dust/Allergen Removal They trapped some dust, but not all of the dust that entered my room. Filter Availability They are supposed to have a built-in filter. Durability Didn't last through a cleaning. Effectiveness Not as effective as I assumed when making the purchase. Design I liked the small tabletop design.