http://www.thermaxaf.com/store/index.php?main_page=product_info&products_id=1170 This is an amazing little thing. You fill the bowl with water, add 10 drops of your fragrance of choice (included) , turn it on, and it cleans/vacuums the air, and makes it smell amazing. I've cooked in my basement many a time, turning this thing on afterwards, and 15 minutes tops you cannot smell anything but the nice clean air. This picture is mine thats on my desk, a little older then the one in the link, but basically the same. If you need to toke privately at home, i highly recommend this product to you!
Damn that joint is 40 bucks? You can do the same thing with an oil burner, and those cost at most $5, unless you want something fancy I doubt that thing actually cleans the air. True air purifiers are expensive. The clean air you're smelling is the fragrance you used