Depending on the underlying geology for the area where you live – you might like to consider the usefulness of having Radon test kits.
The element Radon is a naturally occurring gas formed by the radioactive decay of Radium. This makes Radon a radioactive gas which is colorless, odorless and tasteless; subsequently rendering it undetectable to our natural senses.
One isotope of Radon, with a half-life of a little less than 4 days, is used medically in radiotherapy. However, when occurring naturally it has been established that in high concentrations it can lead to the formation of lung cancer.