Burtran’s mesh metal box may look plain and industrial, but it offers something extra in the world of air purifiers: negative oxygen ion technology. It also uses a HEPA 14, a denser filter than the more ubiquitous HEPA 13s that most air purifiers use. I’ve tested air purifiers for years, and I usually stay away from purifiers that serve up ion technology. In other words, the Burtran has not been proven to create ozone, so I had to wonder, would this proprietary technology actually improve my sleep? Breathe SafeThe second issue with negative oxygen ion technology—even bigger than ozone—is the possible release of radiation.