Add Radon device class

Feature Requests
1

Radon is a serious issue in much of the world. While Airthings and other monitors can be added there is no default device class for radon and the two most common measurement types. Users have to craft integrations and do measurement conversions on their own.

This seems odd given we have CO2 and other gasses (N2O, NO, NO2, CO) as sensor device classes

2

I support your request. However you guys these days don’t know how lucky you are.

Back in the day: Unit conversion? Don’t be a nancy, just use a template. Device class? No such thing.

3

I can appreciate the journey here @nickrout . It’s not just about the conversion, though. These are the (sensor) device classes I’m talking about

Sensor - Home Assistant