Friday, March 9, 2018

Cell Phone Towers are Largest Contributor to Environmental Radiofrequency Radiation




New Study Shows that Cell Phone Towers are Largest Contributor 
to Environmental Radiofrequency Radiation Exposure

A new study measuring radiofrequency electromagnetic fields shows considerable variability in exposure in six countries. Cell phone towers are the most dominant contributor.

(Los Angeles, CA, March 9, 2018) Today the journal, Environment International, published online a six-nation study of outdoor exposures to radiofrequency electromagnetic fields (RF-EMF).

Wireless devices and infrastructure emit RF-EMF. However, little is known about how this affects environmental exposures around the world. In the present study, RF-EMF measurements were taken in locations in Australia, Ethiopia, Nepal, South Africa, Switzerland and the United States by means of portable measurement devices. The devices considered exposure from cell phone towers, TV and FM radio broadcast antennas, cell phone handsets and Wi-Fi.

According to Dr. Martin Röösli, Associate Professor at the Swiss Tropical and Public Health Institute and senior author of the paper, “The study demonstrates that total RF-EMF exposure levels in the environment vary widely between different areas. Cell phone tower radiation is the dominant contributor in most outdoor areas.”

Los Angeles was the study site in the United States.

Compared to the other five countries, the US had high exposure levels ranging from 1.4 milliwatts per square meter (mW/m²) in a non-central residential area of Los Angeles to 6.8 mW/m² in a rural center of the city. The median total exposure to RF-EMF across all eight outdoor microenvironments in Los Angeles was 3.4 mW/m².

Today’s outdoor RF-EMF levels in Los Angeles are about 70 times greater than what the EPA estimated forty years ago.

The last time RF-EMF exposure was systematically measured in Los Angeles was in the late 1970’s as part of a 12-city study conducted by the Environmental Protection Agency (EPA) (Tell and Mantiply, 1982). The EPA assessed RF-EMF in 38 outdoor locations in Los Angeles and found that the median population-weighted exposure was 0.05 mW/m². At that that time television and FM radio broadcast antennas were the most important contributors. Hence, since the 1990’s, the implementation of cell phone tower networks has resulted in substantial increase in RF-EMF.

Although this measurement study demonstrates that environmental exposure levels are substantially below regulatory limits, there are still uncertainties about whether the strong increase of RF-EMF in the environment in recent years poses a health risk. Switzerland has implemented precautionary limits for RF-EMF and indeed exposure levels were lowest among all countries participating in the study.

Röösli and his colleagues emphasize that this measurement study contributes to a better understanding of the exposure situation of the general population all over the world and foster the design of future health studies.

Sanjay Sagar, the first author of the paper, and Martin Röösli, are with the Swiss Tropical and Public Health Institute in Basel, Switzerland. Co-authors from the U.S. include Michael Jerrett and Tony Kuo with the UCLA Fielding School of Public Health, Michael Brunjes and Lisa Arangua with the Los Angeles County Health Department,  and Joel Moskowitz with the UC Berkeley School of Public Health.

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Sagar S, Adem SM, Struchen B, Loughran SP, Brunjes ME, Arangua L, Dalvie MA, Croft RJ, Jerrett M, Moskowitz JM, Kuo T, Röösli M. Comparison of radiofrequency electromagnetic field exposure levels in different everyday microenvironments in an international context. Environment International, 114: 297-306. Published online ahead of print, March 9, 2018.

Highlights

We measured RF-EMF in 94 matched microenvironments in six countries.
We applied a common protocol for direct comparison of RF-EMF.
Downlink and broadcasting exposure was most relevant in outdoor microenvironments.
Uplink is only relevant in public transport with the highest in Switzerland.
Exposure in urban areas tended to be higher.

Abstract

Background: The aim of this study was to quantify RF-EMF exposure applying a tested protocol of RF-EMF exposure measurements using portable devices with a high sampling rate in different microenvironments of Switzerland, Ethiopia, Nepal, South Africa, Australia and the United States of America.

Method: We used portable measurement devices for assessing RF-EMF exposure in 94 outdoor microenvironments and 18 public transport vehicles. The measurements were taken either by walking with a backpack with the devices at the height of the head and a distance of 20–30 cm from the body, or driving a car with the devices mounted on its roof, which was 170–180 cm above the ground. The measurements were taken for about 30 min while walking and about 15–20 min while driving in each microenvironment, with a sampling rate of once every 4 s (ExpoM-RF) and 5 s (EME Spy 201).

Results: Mean total RF-EMF exposure in various outdoor microenvironments varied between 0.23 V/m (noncentral residential area in Switzerland) and 1.85 V/m (university area in Australia), and across modes of public transport between 0.32 V/m (bus in rural area in Switzerland) and 0.86 V/m (Auto rickshaw in urban area in Nepal). For most outdoor areas the major exposure contribution was from mobile phone base stations. Otherwise broadcasting was dominant. Uplink from mobile phone handsets was generally very small, except in Swiss trains and some Swiss buses.

Conclusions: This study demonstrates high RF-EMF variability between the 94 selected microenvironments from all over the world. Exposure levels tended to increase with increasing urbanity.

Open Access Paper (available until April 27, 2018): http://bit.ly/6nationRFstudy

Supplemental Material: http://bit.ly/6nationsupplement

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Tell and Mantiply. Population exposure to VHF and UHF broadcast radiation in the United States. Radio Science. 17(5S):39S-47S. 1982. http://onlinelibrary.wiley.com/doi/10.1029/RS017i05Sp0039S/epdf




Available for interview:

Joel Moskowitz, Ph.D., School of Public Health, University of California, Berkeley; jmm@berkeley.edu

Prof. Martin Röösli, Ph.D., Swiss Tropical and Public Health Institute, Basel;  martin.roosli@swisstph.ch, https://www.swisstph.ch/en/staff/profile/people/martin-roeoesli/

Sanjay Sagar, Ph.D., Swiss Tropical and Public Health Institute, Basel; sanjay.sagar@swisstph.ch