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

Abstract

Frequency selective human-centric sub 6 GHz electromagnetic measurements in shopping mall Berisha D, Rexhëbeqaj-Hamiti V, Dobruna J, Maloku H, Limani Fazliu Z, Ibrani M. (2024). Frequency selective human-centric sub 6 GHz electromagnetic measurements in shopping mall. Cogent Engineering, 11(1). doi: 10.1080/23311916.2024.2340311. Abstract Limiting human exposure to radio frequency electromagnetic fields in crowded indoor public spaces such as shopping malls, is identified as one of the key metrics in the process of green and digital environment transformation. To assess the exposure levels in shopping malls, we conducted a human centric extensive measurement campaign using three-axial frequency selective measurement equipment. Our study involved various indoor locations within the mall, capturing electrical field levels at different times and days of the week. A total of 529,340 samples were collected during working days, and 430,020 samples were collected during weekends. We measured E-field strength, power density, and calculated total exposures for frequency bands ranging from 88 MHz to 5850 MHz. The presented comparative analysis revealed that mobile communications technologies operating at 900 MHz and 1800 MHz were the main contributors to personal exposure levels in different mall environments. Conclusions This paper presents the exposure levels in shopping malls during different days of the week, obtained through a rigorous 3-month measurement campaign utilizing frequency selective measurement equipment. The collected data underwent careful processing, including screening of each measured E- field exposure level to ensure accurate sampling and minimize errors. The average total E-field exposure value during the weekday was 0.39 V/m, while during the weekend 0.33 V/m. The highest contributors to the total exposure levels in various shopping mall environments are mobile communication technologies operating at 900 MHz and 1800 MHz (2G–3G–4G). The Downlink 2G–3G operating at 900 MHz, has an average electric field exposure value of 0.2 V/m during the weekdays and during the weekend, while the Downlink 2G–4G operating at 1800 MHz has an average E-field value of 0.1 V/m during the weekdays and 0.17 V/m during the weekend. On weekdays, the main factor contributing to total exposure levels was 2G–3G mobile communications operating at 900 MHz (Downlink), accounting for 52.4% of the exposure, followed by mobile communications at 1800 MHz (Uplink and Downlink. Furthermore, the highest E-field values during weekdays were observed in the Downlink 2G–3G band and Wi-Fi 2 G technology, exceeding the upper limit of 6 V/m. During the weekend, the primary contributor to total exposure levels remained the 2G–3G communications at 900 MHz (Downlink), accounting for 37% of the exposure. However, there was an increase in e-field values for 2G–4G communications at 1800 MHz (Downlink), with its contribution rising to 34% compared to 15% during weekdays. The highest observed value was for Wi-Fi 5G technology, reaching 4.98 V/m, although its contribution to the total exposure levels was only 0.6%. Based on the cumulative distribution analysis, it can be inferred that during the weekdays, 90% of the measured data have an E-field exposure value of less than 1 V/m. On the other hand, during the weekend, 90% of the measured data have a value smaller than 0.64 V/m. These values are in line with the E-field values recorded in similar studies as referenced in. In conclusion, based on our extensive measurement campaign, personal exposure levels are higher in shopping malls during the weekdays compared to the weekend. The highest contributors to the total personal exposure at shopping malls are the Mobile communication technologies (Uplink/Downlink) and WI-FI technologies. Contrary to our initial expectations regarding the indoor environment of the shopping mall, our measurement data reveals that Wi-Fi technologies are not the primary contributors to the total exposure. Instead, mobile communication technologies operating at 900 MHz and 1800 MHz have emerged as the dominant sources due to their high data rates and extensive coverage. tandfonline.com

AI evidence extraction

Main findings

A frequency-selective, three-axial measurement campaign in a shopping mall (88–5850 MHz) collected 529,340 samples on weekdays and 430,020 on weekends. Average total E-field exposure was 0.39 V/m on weekdays and 0.33 V/m on weekends; mobile communications at 900 MHz and 1800 MHz were the main contributors to total exposure, while Wi‑Fi contributed relatively little despite some high observed values.

Outcomes measured

• Electric field (E-field) strength (V/m)
• Power density
• Total exposure (calculated)
• Band-specific contribution to total exposure (e.g., 900 MHz, 1800 MHz, Wi‑Fi 2G/5G)
• Cumulative distribution of E-field exposure (e.g., 90th percentile)

Suggested hubs

• school-wi-fi (0.15)
  Includes Wi‑Fi exposure measurements, but setting is a shopping mall (not a school).
• 5g-policy (0.1)
  Covers sub-6 GHz RF including Wi‑Fi 5G; not primarily about 5G cellular policy.

{
    "study_type": "exposure_assessment",
    "exposure": {
        "band": "RF",
        "source": "shopping mall indoor environment (mobile communications and Wi‑Fi)",
        "frequency_mhz": null,
        "sar_wkg": null,
        "duration": "3-month measurement campaign; measurements at different times and days (weekdays vs weekends)"
    },
    "population": null,
    "sample_size": null,
    "outcomes": [
        "Electric field (E-field) strength (V/m)",
        "Power density",
        "Total exposure (calculated)",
        "Band-specific contribution to total exposure (e.g., 900 MHz, 1800 MHz, Wi‑Fi 2G/5G)",
        "Cumulative distribution of E-field exposure (e.g., 90th percentile)"
    ],
    "main_findings": "A frequency-selective, three-axial measurement campaign in a shopping mall (88–5850 MHz) collected 529,340 samples on weekdays and 430,020 on weekends. Average total E-field exposure was 0.39 V/m on weekdays and 0.33 V/m on weekends; mobile communications at 900 MHz and 1800 MHz were the main contributors to total exposure, while Wi‑Fi contributed relatively little despite some high observed values.",
    "effect_direction": "unclear",
    "limitations": [],
    "evidence_strength": "insufficient",
    "confidence": 0.7399999999999999911182158029987476766109466552734375,
    "peer_reviewed_likely": "yes",
    "keywords": [
        "shopping mall",
        "indoor",
        "human-centric",
        "frequency selective",
        "three-axial measurements",
        "sub 6 GHz",
        "88–5850 MHz",
        "E-field",
        "power density",
        "personal exposure",
        "2G",
        "3G",
        "4G",
        "900 MHz",
        "1800 MHz",
        "Wi‑Fi"
    ],
    "suggested_hubs": [
        {
            "slug": "school-wi-fi",
            "weight": 0.1499999999999999944488848768742172978818416595458984375,
            "reason": "Includes Wi‑Fi exposure measurements, but setting is a shopping mall (not a school)."
        },
        {
            "slug": "5g-policy",
            "weight": 0.1000000000000000055511151231257827021181583404541015625,
            "reason": "Covers sub-6 GHz RF including Wi‑Fi 5G; not primarily about 5G cellular policy."
        }
    ]
}

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