ARPANSA - Australian Radiation Protection and Nuclear Safety Agency

What is an ARPANSA Environmental EME Report?

The ARPANSA Environmental EME Report (abbreviated to ARPANSA EME Report on this page) is a statement of the maximum predicted levels of radiofrequency electromagnetic energy (EME) that will be produced around a proposed mobile phone base station or antenna following an installation or upgrade of equipment. The report will generally be produced by a mobile phone network company or consultants working on their behalf.

All deployment of mobile phone infrastructure in Australia, which includes base stations and new antennas, must be carried out according to an industry Code of Practice, the ACIF Code. The ACIF Code requires the supply of certain information as part of the consultative process with the local community and local government authority. The ARPANSA EME Report is part of this process and is produced according to a methodology developed by the Australian Radiation Protection and Nuclear Safety Agency (ARPANSA). It provides objective estimates of the maximum levels of EME from the base station following the installation of new or upgraded mobile phone base station equipment.

Why is there an ARPANSA EME Report?

Mobile phone base stations work by sending out radiofrequency (RF) EME in the form of waves carrying information. When the RF EME reaches objects, including people and animals, some of the energy carried by the waves is absorbed by the object. This can lead to heating of the object and, if levels are too high, can cause harmful effects. The ARPANSA Radiofrequency Standard provides limits of exposure with which all radio installations, including mobile phone base stations, must comply. The limits for EME exposure given in the ARPANSA Standard are intended to provide protection for people of all ages and medical conditions when exposed 24 hours per day, 7 days per week. The ARPANSA EME Report shows the maximum predicted levels from a proposed installation.

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What information is on the report?

The report gives the address of the installation, together with a list of the companies using the site and the types of mobile network currently installed and being proposed. It also includes details of calculated levels of RF EME. If the site already has antennas in place, the report includes separate information on the existing and for the combined existing and proposed installations. The report estimates RF EME from all of the identified mobile phone transmitters at this site. The calculated levels do not include RF EME from other types of radio transmitters which may be installed on the same structure as the mobile phone equipment.

EME Levels

The tables of predicted EME levels on the report provide maximum levels of EME found at various distances from the base of the tower or supporting structure. Within each range of distances, the highest value is given regardless of direction. The values of EME are given as percentages of the permitted limit in the ARPANSA Standard. On this scale, a value of 100% corresponds to the general public exposure limit. A typical highest value of 1% means that the total EME level from all mobile phone transmitters on the site, all operating at their maximum power, will be no more than one hundredth (1/100) of the limit set by the ARPANSA Standard for members of the public.

Effect of Landscape (topography)

The tables of predicted EME levels provide values calculated at 1.5 m above a flat landscape. Commonly, base stations are located on a high point and the assumption of flat ground provides a worst-case estimate for these situations. Sometimes, however, the ground may slope upwards away from the base station and this can cause concern that levels may be higher than predicted. In these cases an additional table, “Other Areas of Interest”, may be included to provide levels of EME at a selection of heights where maximum levels are expected.

Other Areas of Interest

The ACIF Code requires the companies to take account of community concern about locations of particular interest, such as places where children spend a lot of time, or multistorey residential buildings facing the antennas. The table “Other Areas of Interest” on the report provides additional estimates of EME levels at a small number of such locations. These locations may be identified during the ACIF consultation process as being of particular community concern. Typically, levels may be given for the closest point of a children’s facility, or for a small number of other locations.

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Why do the EME levels vary with distance?

The calculations of the maximum levels are based on well understood principles of physics that deal with how electromagnetic waves travel and spread out. The total amount of energy emitted from the antenna is limited by the power of the amplifier used and cannot exceed a certain specified amount. As the energy leaves the antenna, it spreads out to cover bigger and bigger areas and so gets less intense the further away it gets.

The antenna is usually designed to direct most of the energy out towards the horizon, or a few degrees below, so that most of the energy goes where it is needed to communicate with the mobile phone handsets furthest away. As one moves along the ground, the levels first increase as you move away from the base station up to a maximum and then get less as you move still further away. Typically, the maximum EME level at ground level will occur between 75 m and 200 m from the base of the antenna.

The companies sometimes need to adjust the angle of the antennas to obtain the best coverage and this can alter slightly the distance at which the maximum occurs and exactly what EME level is found there. Often, the ARPANSA EME Report will take likely alterations into account and include the highest levels that might occur if the antenna is moved in the future.

How Accurate are the Calculated Values?

The values of EME provided in the report are intended to be maximum levels that can almost never be exceeded when the base station is operating. The values assume, for example, that all the planned transmitters are installed and are all operating at maximum power. Some of the transmitters at a base station are only used when there are a certain number of telephone calls actually in progress; otherwise they are turned off. Even when a call is in progress, the power transmitted is adjusted to be only as high as necessary to communicate with the handset. If the handset is close, or in a good signal area, the base station transmitter will reduce its power automatically.

The calculations do not take into account trees, vegetation or buildings which may alter the EME levels, generally decreasing them. Some of the EME is reflected from buildings and the ground and often this signal is used by a handset when the direct signal is blocked by a building. When the reflected signal and direct signal combine the overall level can be lower or higher than the direct signal alone depending on the exact location.

Measurements around base stations have shown actual values of EME are usually less than calculation by factors of 10 to 1000 or even more. Values of EME indoors will typically be even lower as walls, windows and roofs absorb or reflect the energy.

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Example Table of Predicted EME Levels

The example table below provides the following information.

• The predicted highest level of RF EME coming from this base station is found at a distance of 175 m and is 0.37% or approximately 1/270 of the ARPANSA Standard exposure limit. This value is only expected to occur when the transmitters are all operating at full power and where there is clear line-of-sight to all antennas. Levels indoors will be lower.
• At any location within 50 m of the base of the tower, the EME levels should not exceed 0.02% or 1/5000 of the ARPANSA Standard exposure limit.
• At a location 330 m from the tower, that is between 300 m and 400 m, the predicted level will be less than 0.16%, or 1/625 of the ARPANSA Standard exposure limit. In many directions, and at most times, the actual level will be much lower than this predicted level.

Predicted EME Levels – “existing and proposed” or “proposed”

Distance from the antennas at Base station address in 360? circular bands	Maximum Cumulative EME Level – All mobile services (Fraction of ARPANSA exposure limit) Public exposure limit = 100%
0m to 50m 50m to 100m 100m to 200m 200m to 300m 300m to 400m 400m to 500m	0.02% 0.02% 0.37% 0.32% 0.16% 0.08%
Maximum EME level 1.5 m above ground, 174.73 m from the antennas at Base station address	0.37%

For a new base station where there are no antennas already installed, the report will contain a single table of this kind. Where a base station is being upgraded, two tables of this kind will be included, one for the existing installation and one for the upgraded installation.

Example Other Areas of Interest Table

Other Areas of Interest Table

Additional Locations	Height/Scan relative to location ground level	Maximum Cumulative EME Level – All Carriers at this site (Fraction of ARPANSA exposure limit) Public exposure limit = 100%
SeaView Apartments 321 Beach Parade.	0m to 30m	0.011
ACME Health Solutions Level 1, Hillcrest Crt.	2m - 5m	1.8
Play & Learn Child Care (Adventure playground, NW corner)	0m to 10m	0.16

The “Other Areas of Interest” table provides predicted levels of RF EME at locations considered to be of special community interest or at elevated locations where there may be concern about higher levels of EME.

Where is more information available?

ACIF Code of Practice (PDF 660kb)

ARPANSA Radiation Protection Standard No.3 (RPS3)- Maximum Exposure Levels to Radiofrequency Fields - 3kHz to 300GHz

Australian Communications and Media Authority

 

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