Exposure to extremely low frequency magnetic fields in an urban area.

Magnetic field levels were studied in an urban area--the city of Cáceres (Spain). The study included systematic spot measurements throughout the city, an analysis of the temporal variation of the magnetic field, and the incorporation of the data into a geographic information system. The levels detected were at most 7.3% of the ICNIRP reference levels, and the highest fields were found in the oldest neighborhoods. Considered overall, the ELF magnetic flux density levels determined in the present study were between those found in residential and in working environments. Knowledge of the levels of such fields in urban areas is therefore fundamental in evaluating the population's overall exposure, especially for people who work outdoors.