Experimental Evaluation of Distance-Dependent User Exposure to Extremely Low-Frequency Magnetic Fields from Computer Devices Under Typical Operating Conditions

Abstract

Extremely low-frequency (ELF) magnetic fields emitted by information technology equipment have raised public health concerns regarding continued occupational and academic exposure. As computers become essential tools in higher education, enumerating user contact levels is crucial for establishing safety baselines and promoting optimized best practices. This study therefore, evaluated user exposure to extremely low-frequency (ELF) magnetic fields at varying distances from computer devices at the National Open University of Nigeria, Abuja. Ten commonly used desktop and laptop computer models operated continuously for 90–120 minutes prior to measurement. A calibrated GM3120 electromagnetic field meter was used to measure ELF magnetic field strength at distances of 10cm, 20cm, 30cm, 50cm, and 100cm from the front and rear surfaces of the devices. Preliminary measurements indicated the ELF magnetic field measurements from the left and right sides of the devices were insignificant. The experimental results demonstrated that magnetic field strength decreased consistently as the distance from the computer screens increased. For the front screen, radiation values ranged from 0.05 to 2.43 milliGauss (mG) at the closest measurement distance (10 cm), dropping significantly to between 0.01 and 1.04 mG at a 100 cm. Similarly, rear-surface measurements ranged from 0.03 to 0.90 mG at 10cm and decreased to between 0.01 and 0.30 mG at 100cm. Notably, modern laptop models like the Apple MacBook Air M4 and Dell XPS 13 emitted the lowest overall radiation levels. The study concludes that increasing the distance between users and computer devices from both desktop and laptop computer screens significantly minimizes personal exposure to ELF magnetic field exposure