Map of radon zones

{
  "id": "MLC-T-ENV-016512",
  "term": "Map of radon zones",
  "field": "Environment",
  "term_source": "Map of Radon Zones",
  "definition": "EPA's Map of Radon Zones assigns each of the 3,141 counties in the United States to one of three zones based on radon potential: 1) Zone 1 Counties have a predicted average indoor screening level greater than 4 pCi/L; 2) Zone 2 Counties have a predicted average indoor screening level between 2 and 4 pCi/L; 3) Zone 3 Counties have a predicted average indoor screening level less than 2 pCi/L; Elevated radon have been found in all counties (Zone 1, Zone 2 and Zone 3), see also -www.epa.gov/radon/zonemap.html",
  "subject": "Air",
  "references": [
    "RRNC Glossary of Terms"
  ],
  "url": "https://mlchart.com/terminology/environment/map-of-radon-zones/"
}