Large-area mobile measurement of outdoor exposure to radio frequencies

Abstract

Overview

A pioneering outdoor sampling technique was developed and evaluated for measuring human exposure to radio frequencies within a moderately populated city. This technique leveraged a personal exposure meter mounted inside a moving vehicle to facilitate large-scale data collection.

Methodology

• Measurements were taken from 3065 different points within the city where signals from both FM radio and mobile phone bands were present.
• The structural impact of the vehicle was assessed to adjust the data, ensuring accurate exposure readings despite the vehicle’s interference.
• Techniques such as Kriging were applied to create detailed exposure maps, which were then integrated with aerial photos for enhanced visual analysis of the data.

Findings

The methodology effectively captured a wide range of radio frequency levels across various bands, with calculated exposure quotients indicating substantial variability in exposure throughout the city. Notably, while the vehicle amplified FM radio signals, it reduced mobile telephony signal levels, suggesting differential effects based on frequency and source. Prominent electric field levels measured include:

• FM: 0.231 V/m
• LTE 800 (DL): 0.057 V/m
• GSM + UMTS 900(DL): 0.140 V/m
• GSM 1800(DL): 0.124 V/m
• UMTS 2100(DL): 0.110 V/m

Conclusion

The developed sampling method proves to be an effective, scalable tool for assessing RF exposure in different urban settings and times, highlighting the possibility of significant exposure to electromagnetic fields which could pose health risks.