Instruct: Classify Amazon reviews into positive or negative sentiment
Query: Loud, ineffective

Do not waste your money on this. I wish I had paid more heed to the reviews that noted how loud this purifier is. It is not quiet - aside from being loud on its own, after the third day of use it started to rattle as if the parts inside had come undone and were clanking around. I followed all of the included instructions and thus far haven't experienced an improved quality in the air of the bedroom where I've set up the machine. (I've had the purifier for two weeks). It's basically an incredibly loud, irritating, paper weight at this point.