Instruct: Classify a review into positive or negative sentiment.
Query: Incredible! The best on the market.

I purchased this after recommendation of a co-worker. I have awlful year round allergies, particularly to dust, dust mites, mold and pollen. I was amazed the first night, I had the best night sleep and my sinus felt great. I'm amazed at the amount of airbourne pollution it grabs. Keeping it clean weekly keeps it running in top condition.I've tried other air purifiers but this one has done what it claims. I've purchased two and run them 24 hours. I'm glad that them.