I had been subject to a lot of neighbour smells. One of my neighbours left smelly shoes outside and the smell found it's way into my bedroom in my warddrobe and my bed. I had a second neighbour who cooked very spicy food and that all brought smells and mixed with the other. One day I just couldnt smell any clean air. I bought this item and it is wonderfull. All the smells in my room including the clothes and the bed were all gone in 24 hours. The instrument is very quiet (very quiet fan)and the air smells like I have had the windows open all day. The room does not smell of anything anymore. It was a relief that I can have a clean flat agaian after one year of frustration of air freshners. I need quiet for nighttime and on low it does makes a quiet noise (quieter than aircons). I slept through it.