I know that is not some standard equipment for a smart home system, but there are very affordable kits that work very well. Also measuring gamma radiation is cool
This is a good place where I could reach many people that can connect the readily available kit with their home automation systems and also provide the data to the public so we can have a better picture world-wide.
I modified some of the existing code available online and uploaded it on git: http://tiny.cc/cmx4hz
It is based on Arduino and ethernet module that publish the data to MQTT
I will provide more technical details there but keed this thread for communication/question. This topic was created after some people were inspired by my screenshot here
There is a free site where you can publish the data from your measurements too: