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Estimated Average Magnetic Field Exposure of the U.S. Population

Average 24-hour
field (mG)

Population
exposed (%)

95% confidence
interval (%)

People exposed*
(millions)

> 0.5
> 1
> 2
> 3
> 4
> 5
> 7.5
> 10
> 15

76.30
43.60
14.30
06.30
03.60
02.42
00.58
00.46
00.17

73.8-78.9
40.9-46.5
11.8-17.3
4.7-8.5
2.5-5.2
1.65-3.55
0.29-1.16
0.20-1.05
0.035-0.83

197-211
109-124
31.5-46.2
12.5-22.7
6.7-13.9
4.4-9.5
0.77-3.1
0.53-2.8
0.09-2.2

*Based on a population of 267 million. This table summarizes some of the results of a study that sampled about 1,000 people in the United States. In the first row, for example, we find that 76.3% of the sample population had a 24-hour average exposure of greater than 0.5 mG. Assuming that the sample was random, we can use statistics to say that we are 95% confident that the percentage of the overall U.S. population exposed to greater than 0.5 mG is between 73.8% and 78.9%.
Source: Zaffanella, 1993.

Estimated Average Magnetic Field Exposure of the U.S. Population for Various Activities

Population exposed (%)

Average field (mG)

Home

Bed

Work

School

Travel

> 0.5
> 1
> 2
> 3
> 4
> 5
> 7.5
> 10
> 15

69
38
14
7.8
4.7
3.5
1.2
0.9
0.1

48
30
14
7.2
4.7
3.7
1.6
0.8
0.1

81
49
20
13
8.0
4.6
2.5
1.3
0.9

63
25
3.5
1.6
> 1

87.0
48.0
13.0
4.1
1.5
1.0
0.5
> 0.2

Source: Zaffanella, 1993.