Study of the Correlation between Outdoor and Indoor Electromagnetic Exposure near Cellular Base Stations in Leuven, Belgium

Abstract

Study of the Correlation between Outdoor and Indoor Electromagnetic Exposure near Cellular Base Stations in Leuven, Belgium NkemIyare R, Volskiy V, Vandenbosch G. Study of the Correlation between Outdoor and Indoor Electromagnetic Exposure near Cellular Base Stations in Leuven, Belgium. Environmental Research. Publ online 22 Aug 2018. doi.org Highlights • GSM 900 is the dominating source of exposure • Exposure levels meet international recommendations and local legislation • In absolute levels the outdoor field exposure is ca. the double of the indoor field exposure • EM exposure levels are reproducible over a time span of ca. one month Abstract A measuring campaign for the assessment of electromagnetic radiation near base stations in the city center of Leuven, Belgium, has been carried out. The main objective of this assessment is to study the correlation between the outdoor and the indoor exposure produced by cellular base stations and to investigate the changes of electromagnetic exposure within a typical day and over 1 month in the vicinity of these base stations. The study was also carried out as a function of location and time using highly precise measurement equipment. The measurements were performed in both public and private areas in sixty (30 indoor and 30 outdoor) different locations in Leuven. The measurement was focused on mobile communication networks: GSM (Global System for Mobile Communication, 900 MHz and 1800 MHz) and UMTS (Universal Mobile Telecommunications System, 2110 MHz) were the frequency bands of interest. The data at these frequencies were extracted from raw measurements in the 824 MHz to 2170 MHz frequency band. The results show that all analyzed locations are in compliance with the exposure limits recommended by ICNIRP (International Commission on Non-Ionizing Radiation Protection) and that the (maximum) indoor exposure correlates to the outdoor exposure with a factor of about 0.5. Conclusions The electromagnetic radiation exposure of the general public generated by base stations in Leuven, Belgium, was duly assessed using spectrum analyzer measurements at 60 locations and at several moments during the day. All measured values are considerably below norm levels for Flanders, which means that they are far below the ICNIRP exposure limits for the general public. The average levels over time and over the whole city center are: outdoors about 0.64 V/m for GSM 900, 0.53 for GSM 1800, and 0.33 for UMTS, and indoors about 0.32 V/m for GSM 900, 0.26 for GSM 1800, and 0.17 for UMTS. To the average, the outdoor exposure levels are thus a factor of two higher than the indoor levels. In general, the dominating source of exposure is GSM 900. The maximum field value measured was equal to 1.80 V/m, due to the GSM 900 signal. In this study, the average effect of absorption and reflection, typically used to explain the lower values indoors, is in agreement with the average attenuation through walls used in propagation models. sciencedirect.com

AI evidence extraction

Main findings

Measurements at 60 locations (30 indoor, 30 outdoor) in Leuven found GSM 900 to be the dominant exposure source. All analyzed locations were reported to be compliant with ICNIRP recommendations and Flanders norms; outdoor average levels were about twice indoor levels, with maximum measured field 1.80 V/m (GSM 900), and indoor exposure correlated with outdoor exposure by a factor of ~0.5.

Outcomes measured

• Outdoor electric field strength (V/m) in GSM 900, GSM 1800, UMTS bands
• Indoor electric field strength (V/m) in GSM 900, GSM 1800, UMTS bands
• Indoor-outdoor exposure correlation/ratio
• Compliance with ICNIRP and local (Flanders) exposure limits
• Temporal reproducibility/variation over a day and over ~1 month
• Dominant source band contributing to exposure

Limitations

• No health outcomes assessed (exposure measurement study only)
• Frequency bands analyzed limited to GSM 900/1800 and UMTS 2110 MHz (extracted from 824–2170 MHz measurements)
• Geographic scope limited to Leuven city center and 60 locations

Suggested hubs

• who-icnirp (0.7)
  Study explicitly evaluates compliance with ICNIRP exposure limits/recommendations.

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    "study_type": "exposure_assessment",
    "exposure": {
        "band": "RF",
        "source": "cellular base station",
        "frequency_mhz": null,
        "sar_wkg": null,
        "duration": "within a typical day and over 1 month"
    },
    "population": "general public (measurements in public and private areas in Leuven, Belgium)",
    "sample_size": 60,
    "outcomes": [
        "Outdoor electric field strength (V/m) in GSM 900, GSM 1800, UMTS bands",
        "Indoor electric field strength (V/m) in GSM 900, GSM 1800, UMTS bands",
        "Indoor-outdoor exposure correlation/ratio",
        "Compliance with ICNIRP and local (Flanders) exposure limits",
        "Temporal reproducibility/variation over a day and over ~1 month",
        "Dominant source band contributing to exposure"
    ],
    "main_findings": "Measurements at 60 locations (30 indoor, 30 outdoor) in Leuven found GSM 900 to be the dominant exposure source. All analyzed locations were reported to be compliant with ICNIRP recommendations and Flanders norms; outdoor average levels were about twice indoor levels, with maximum measured field 1.80 V/m (GSM 900), and indoor exposure correlated with outdoor exposure by a factor of ~0.5.",
    "effect_direction": "no_effect",
    "limitations": [
        "No health outcomes assessed (exposure measurement study only)",
        "Frequency bands analyzed limited to GSM 900/1800 and UMTS 2110 MHz (extracted from 824–2170 MHz measurements)",
        "Geographic scope limited to Leuven city center and 60 locations"
    ],
    "evidence_strength": "moderate",
    "confidence": 0.7800000000000000266453525910037569701671600341796875,
    "peer_reviewed_likely": "yes",
    "keywords": [
        "base stations",
        "RF exposure",
        "indoor",
        "outdoor",
        "GSM 900",
        "GSM 1800",
        "UMTS 2110",
        "ICNIRP",
        "Leuven",
        "Belgium",
        "electric field strength",
        "V/m",
        "spectrum analyzer"
    ],
    "suggested_hubs": [
        {
            "slug": "who-icnirp",
            "weight": 0.6999999999999999555910790149937383830547332763671875,
            "reason": "Study explicitly evaluates compliance with ICNIRP exposure limits/recommendations."
        }
    ]
}

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