General radon levels in the environment can vary greatly, depending on locale and the medium it is measured in. Here are comparisons between indoor/outdoor air, soil air and groundwater.

Again, the conversion factors are from the picoCurie/liter to the Becquerel / m^3:

1 picoCurie / liter = ~ 37.1 Bq/m^3     EPA action limit 4 pCi/L = ~ 148.4 Bq/m^3

 

Radon:  Outdoor air      Low of 4 – 8 Bq / m^3    =  0.2 – 0.3 picoCuries/liter

High of 100 Bq / m^3 in valleys (morning time)  = 2.7 picoCuries / liter

Radon:  Indoor air  Low  20 Bq / ^3  = 0.5 pCi/l

High of 110000 Bq / m^3  = 2964 pCi/l  (probably over a uranium mine)

 

World average  39 Bq / m^3   = 1.1 pCi/l

 

EXAMPLE INDOOR RADON LEVELS by Country: Average

Egypt:   9 = 0.2 pCi/l

UK:  20 =  0.5 pCi/l

USA:  46 = 1.5 pCi/l     Texas  48 = 1.3 pCi/l

United States by Region:  (geometric mean values)  3.43 pCi/L in the Northeast   2.36 pCi/L in Midwest, 0.64 in the Northwest, 2.40 pCi/L in the Mountain States, 1.43 pCi/L in the Southeast

Sweden:  108   = 2.9 pCi/l

Czech Republic: 108 = 2.9 pCi/l

Highest ever radon concentration ever reported in an indoor dwelling:   2600 pCi/L in a southeastern Pennsylvania home which is equal to a 4 pack a day smoker.

Radon in soil air:   Ranges from less than 1 to over 2500 Bq / liter  = 0.03 – 67.4 pCi/l

Most soils in the USA are between 5 – 55  Bq/liter  = 0.13 – 1.48 pCi/l

Radon in groundwater:  3 – 80000 Bq/liter  = 0.081 – 2156 pCi/l