Study of Electromagnetic Field Exposure from GSM Base Stations in Ibadan Metropolis

The proliferation of global system for mobile communications base transceiver stations in Nigerian urban centers has raised public concern about potential health effects of prolonged radiofrequency electromagnetic field exposure. This study measures and characterizes electromagnetic field intensities emitted by selected GSM base stations in Ibadan, Oyo State, South West Nigeria. Using a calibrated tri-axial radiofrequency electromagnetic field meter, power density and electric field strength measurements were taken at distances of 10, 20, 50, 100, and 200 meters from twelve active base stations across residential, commercial, and peri-urban zones. Measurements were conducted during morning, afternoon, and evening periods to capture temporal variation in emission profiles. Recorded values are compared against International Commission on Non-Ionizing Radiation Protection reference levels for general public exposure. Results indicate that all measured power density values fall below the 900 MHz ICNIRP limit of 4.5 W/m2, with maximum recorded values of 0.038 W/m2 at 10 meters from transmitter antennas. However, cumulative exposure from multiple co-located base stations in certain commercial zones showed additive electromagnetic loading that warrants continued monitoring. The study recommends mandatory regular environmental electromagnetic field assessments in densely populated urban areas. A standardized methodology for community-level RF exposure monitoring in Nigeria is proposed. Keywords: electromagnetic field, GSM base station, radiofrequency exposure, Ibadan, ICNIRP