Frequency selective human-centric sub 6 GHz electromagnetic measurements in shopping mall

Abstract

Overview

Limiting human exposure to radio frequency electromagnetic fields in crowded indoor public spaces such as shopping malls is identified as a key metric in the process of green and digital environment transformation. This study aimed to assess exposure levels in shopping malls through a human-centric, extensive measurement campaign using three-axial frequency selective measurement equipment.

Methodology

• Measurement campaign conducted in various indoor locations within a shopping mall
• Measurements captured at different times and days of the week
• A total of 529,340 samples collected on weekdays, 430,020 samples on weekends
• Frequency bands measured ranged from 88 MHz to 5850 MHz
• E-field strength, power density, and total exposures calculated

Findings

• Main contributors: Mobile communication technologies at 900 MHz and 1800 MHz contribute most to personal exposure levels.
• Average total E-field exposure: 0.39 V/m (weekday), 0.33 V/m (weekend)
• 900 MHz downlink (2G-3G): 0.2 V/m average (both weekdays and weekends)
• 1800 MHz downlink (2G-4G): 0.1 V/m (weekdays), 0.17 V/m (weekend)
• 52.4% of exposure on weekdays from 900 MHz downlink; 37% on weekends
• Highest E-field during weekdays observed in Downlink 2G-3G and Wi-Fi 2G, exceeding 6 V/m (notable safety concern)
• Wi-Fi 5G highest observed value: 4.98 V/m (weekend, but only 0.6% contribution overall)
• 90% of measured E-field values < 1 V/m (weekdays); < 0.64 V/m (weekends)

Conclusion

Personal exposure levels are higher during weekdays compared to weekends in shopping malls, largely due to mobile communication technologies. Contrary to expectations, Wi-Fi technologies are not the primary source; instead, mobile communication at 900 MHz and 1800 MHz are predominant due to their high data rates and extensive coverage. Some measurements exceeded 6 V/m, indicating a potential health risk from EMF exposure in these environments.