I use incense. I don't usually like most incense but I found a brand that are really nice. Most things just make an attempt to cover up the smell where as these actually blend in with the smell making it a completely different one. They are called gonesh sticks. I get mine from the dollar store but they have a website. Gonesh I also like scented candles but they don't take effect as fast as lighting one of these.
CArbon Filter---- ozone generator-- carbon sheet's --- homemade air purifier in the DIY secton i think.. pick one.. or u can just be ghetto and use candles n shit