There are some regional differences in exposure across the United States, but these are differences that are likely to change based upon the seasons and are not likely to have a major impact upon exposure considerations. The presence of overhead power lines near homes contributes to both personal exposures and fixed home measurements. Combined, the two sources add up to much of the spot residential fields in homes having higher than usual magnetic field levels. A comparison was made between different types of power lines to determine which ones produced the greatest fields. At distances of greater than 50 feet, the type of power lines appeared to have little impact on the average exposure and only a minor impact on the number of individuals with the highest exposures.
Exposures tend to vary greatly by distance to the appliance and type of appliance.
In general, microwave ovens, toaster ovens, ceiling heat and refrigerators generated the highest fields. However, the contributions of these fields to personal exposure will depend upon placement of the appliance, distance from the appliance, frequency of use, manufacturer, etc. Any observations on exposures from appliances are not easily generalized. The list of occupations with ELF-EMF exposure is quite large and will not be repeated here.