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Radon zones in Arizona

The EPA assigns every county in Arizona to one of three radon potential zones. No county in Arizona is in Zone 1. That is a statement about predicted county averages, not about any individual home - homes above the action level are found in all three zones.

15
Counties
0
Zone 1 counties
Predicted average above 4 pCi/L
15
Zone 2 counties
Predicted average 2-4 pCi/L
0
Zone 3 counties
Predicted average below 2 pCi/L

The map

Radon potential across Arizona

Every county in Arizona, filled by the zone the EPA assigns it. Zones follow geology rather than county lines, so the colour usually changes where the bedrock does, not where the border is.

Zone 1 · 0Zone 2 · 15Zone 3 · 0

Hover a county · click to open it

County by county

All 15 Arizona counties

Zone 1 · > 4 pCi/LZone 2 · 2 - 4 pCi/LZone 3 · < 2 pCi/L
CountyZonePopulationCOPDSmokingLung ca. deaths
Apache County265k11.9%22.4%14.0
Cochise County2125k8.3%12.8%31.3
Coconino County2144k6.3%11.5%13.9
Gila County254k10.6%15.4%26.2
Graham County240k7.4%15.2%25.8
Greenlee County29,3695.4%11.6%31.9
La Paz County217k12.5%14.1%38.5
Maricopa County24.6M5.7%10.8%24.3
Mohave County2224k11.2%16.1%40.3
Navajo County2109k10.9%18.8%19.7
Pima County21.1M6.8%10.5%23.8
Pinal County2484k7.5%12.3%24.7
Santa Cruz County249k6.8%11.6%15.7
Yavapai County2249k9.2%12.0%29.3
Yuma County2213k7.5%12.7%22.9

Zones from the EPA Map of Radon Zones. COPD and smoking are CDC PLACES model-based estimates of adult prevalence. Lung cancer death rates are age-adjusted deaths per 100,000 per year, 2019-2023, from NCI State Cancer Profiles. A dash means the source does not report a value for that county.

Other states

Radon zones elsewhere