I’m happy to report that Burtran's claim was correct—its operation did not result in a spike of radioactivity. My entire apartment was measuring around 20 clicks per minute, or CPM—for context, 5-50 CPM is normal background. It’s when the number hits over 2,000 that the GQ GMC Geiger Counter Nuclear Radiation Safety Guide says to evacuate and report it to the government.

Filter Fortitude

Burtran also claims that, with its beefed-up HEPA 14 filters, the Nano-Oxy “captures 99.995 percent of ultra-fine particles down to 0.1 micron, surpassing HEPA 13 efficiency by up to 90 percent.”

HEPA is an acronym for “high-efficiency particulate air.” The number that follows HEPA is the MERV rating, or minimum efficiency reporting value, which measures a filter's ability to capture particles between 0.3 and 10 microns. As the EPA explains, “The higher the MERV rating, the better the filter is at trapping specific types of particles.”

There’s a catch to all that density, though—in certain appliances, MERV 14 can restrict airflow. For example, DIY air pu...