Although smart meters use radio waves to send meter readings to your energy supplier, they don’t pose a risk to health.
The meter readings are sent over a mobile wide area network (WAN) and sent to your home over a secure wireless home area network (HAN). Both networks have been built so that the data you send and receive is always secure.
All smart meters have to meet strict health and safety standards. You can find more information on smart meters and health in this GOV.UK article.