Half life is 1.25 billion years and rate is the inverse of lifetime, so I don't understand why you classify potassium-40 as a "strong" emitter?
Radon-222 has a half life of 3.8 days, so that at least is a strong emitter. Less of it in the environment, but IIRC still the biggest source of background radiation for us.
Radon may not concentrate within the body but it does concentrate within unventilated basements and within valleys in granite heavy areas.
It blows away and expresses fresh from the ground on a daily basis such that prolonged exposure is equivilant to a two|three pack a day smoking habit wrt cancer risk.
