Magnetic Field Measurement of Various Types of Vehicles, Including Electric Vehicles

Abstract

Overview

Since the introduction of electric vehicles (EVs) to the market around the year 2000, there has been increasing public concern regarding the level of magnetic flux density (MFD) experienced inside such vehicles. In response, the researchers conducted comprehensive magnetic field (MF) measurements on modern Japanese EVs, plug-in hybrid electric vehicles (PHEVs), and internal combustion engine vehicles (ICEVs), aligning with the methods outlined in the international standard IEC 62764-1:2022. This builds upon earlier studies, with significant methodological improvements—namely, conducting measurements during actual driving rather than using a chassis dynamometer.

Findings

• All measured MFD values in tested vehicle types were below the reference levels recommended by the International Commission on Non-Ionizing Radiation Protection (ICNIRP) for public exposure.
• MF levels and their sources were mapped for various positions inside vehicles. For EVs and PHEVs, maximum MFs were detected at the rear seat (6.5 cm distance), while for ICEVs it was near the driver's dashboard (20 cm distance).
• PHEVs exhibited the highest MF levels, followed by ICEVs and then EVs.
• Frequency analysis revealed both speed-dependent and speed-independent components, including peaks attributable to magnetized tires and air conditioner operation, as well as wiring and wiper motor activity.
• Comparison with prior 2013 data indicated that vehicle MF levels remain similar in 2025. However, an international comparison uncovered that other studies (e.g., Seibersdorf Laboratory, Austria) reported higher transient MF spikes, pointing to measurement methodology differences.

Conclusion

• Current MF exposures inside Japanese vehicles remain below known thresholds for acute health effects such as nerve stimulation, supporting ICNIRP guideline compliance. However, the study highlights the ongoing need for risk communication due to persistent public concern and the expectation that exposure may rise with improvements in EV performance (increased motor output and battery capacity).
• Regular publication of updated MF measurement results is recommended to maintain transparency as vehicle electrification and new mobility technologies continue to expand.
• The study emphasizes the importance of conducting similar measurements for emerging wireless charging systems and larger vehicles (e.g., buses) for comprehensive EMF safety assessment and risk communication.

⚠️ There is a consistent concern linking EMF exposure in electric vehicles to health risks, underscoring the necessity for continued monitoring and public information.