An online map has revealed the areas of Hertfordshire that are hotspots of radioactive gas.

The interactive tool shows where there are high levels of Radon gas in the county.

The gas, which is colourless, odourless and tasteless, is formed by radioactive decay from the small amounts of uranium that can be found naturally in all rocks and soils.

Public Health England, however, states that "every building contains radon but the levels are usually low.

"The chances of a higher level depend on the type of ground."

Radon is a naturally-occurring radioactive gas that can cause lung cancer.

Outdoors, radon disperses rapidly and, generally, is not a health issue.

On Public Health England’s map, the darker the colour, the greater the chance of a higher level.

In white areas it is approximated there is less than one home out of a hundred with the gas and greater than one in three in the darkest areas.

A broad look at Hertfordshire shows Radon gas is largely found in rural areas, with lower concentrations of the gas in urban sprawls.

Here is how some locations in Hertfordshire fare according to the map:

Rickmansworth and Croxley Green

Hillingdon Times:

St Albans

Hillingdon Times:

Watford and Bushey

Hillingdon Times:

Abbots Langley

Hillingdon Times:

Borehamwood

Hillingdon Times: