Static Fields

2. What are the sources of static electric fields?

The source document for this Digest states:

Static electric fields occur naturally in the atmosphere. Values of up to 3 kV m^-1 can occur under thunderclouds, but otherwise lie in the range 1–100 V m^-1 in fair weather. The next most common cause of human exposure is charge separation as a result of friction. For example, charge potentials of several kilovolts can be accumulated while walking on non-conducting carpets, generating local fields of up to 500 kV m^-1. direct current (DC) power transmission can produce static electric fields of up to 20 kV m^-1, rail systems using DC can generate fields of up to 300 V m^-1 inside the train, and VDUs create electric fields of around 10 - 20 kV m^-1 at a distance of 30 cm.

Source & ©: WHO "Environmental Health Criteria 232: Static Fields" (2006)
 Chapter 1, Section 1.1.1 Natural and Human-made sources

For more information on	See EHC 232
Natural electric fields	Chapter 3, Section 3.1.1
Man-made electric fields	Chapter 3, Section 3.2.1