Instruct: Classify Amazon reviews into positive or negative sentiment
Query: took care of allergies-but very loud

My wife has various allergies and before bed,it was a miserable time for her with sneezes,etc.I got her one of these air purifiers and in only a few days,the allergy symptoms disappeared. These are very effective at cleaning the air.The only drawback is that they are rather loud;so much so that we both turn the unit on "high" as soon as we get home from work and leave them on w/ the door closed until bed-time. So,be warned,they are good and inexpensive air purifiers,but are pretty loud. Some may have no problem w/ leaving them on at night but that didn't work for us.If not for their loudness,I'd give them five stars.