Ultraviolet light can be concerning to some people. We get sunburned from UV light from the sun. It can even go as far as giving us skin cancer. This is dangerous, but this can also be used as a tool to make us healthier, too.
Using UV in an air purifier is one way to go. While it might be scary to have a bulb that produces radiation in your home, these bulbs are coated in a special substance that doesn’t allow the radiation or produced ozone to escape from the bulb. However, with airborne particles and microbes pulled in, they will be destroyed by the bulb.
There’s a lot more explanation at http://www.damagecontrol-911.com/how-does-a-uv-air-purifier-work/
A UV air purifier works similarly to how a bug light works on insects. Though, it can’t be said that air purifiers attract microbes. Instead, it pulls the air in and the microbes will be passively obliterated inside. Thankfully, you don’t have to change a filter unless it’s a combination with the bulb.
However, the bulb does lose effectiveness over time, so you’ll have to replace the bulb every 1-2 years. It’s a relatively new technology, so it might be pretty expensive to find one. You should stay away from the cheaper ones, though, considering their bulbs might not have the protective coating talked about earlier.