Guide to Preparing the Current ARPANSA Environmental EME Report
This information is intended mainly for the guidance of those preparing ARPANSA Environmental EME reports.
However, the information may also be of interest to members of the community seeking more technical details of the information contained in EME reports.
The following guidance is provided to assist in preparing the current ARPANSA Environmental EME reports as required by the Communications Alliance Ltd Industry Code (PDF 1.46 mb).
Guidance for Preparation
The purpose of the ARPANSA Environmental EME report is to provide affected persons in the community with an objective and reliable estimate of the maximum levels of radiofrequency (RF) electromagnetic energy (EME) likely to be emitted by an existing, upgrade to an existing, or proposed mobile phone base station installation. Affected persons are usually those who live, work or play in close proximity to base station antennas. For practical purpose some limitations on the complexity of the calculation is necessary. Details of acceptable methods of carrying out the assessment of EME levels are provided in Prediction methodologies - Radiofrequency EME exposure levels .
A Single Report Format
Since its revision in 2013, there is a single format used for the ARPANSA Environmental EME report whether it refers to a new proposed installation or to an existing site for which an upgrade is being proposed. The calculated values of RF EME for the existing transmitting equipment and any proposed changes are now presented side-by-side in a single table.
The report should clearly identify the site that is being considered in a way that both the telecommunications companies involved and community members may understand. Precise street addresses and well-known names of buildings should be provided rather than geographical references that may become ambiguous in time (as, for example 'corner of Smith and Brown Streets').
The assessment of EME is intended to include all mobile phone emissions from the site under consideration. The address given for the site should be specific enough that there is no misunderstanding about which installations are included. This may require a more detailed address such as 'South tower, 12 Smith St, Brownville'.
Radio Systems at the Site
The descriptors for radio systems consist of a prefix indicating the transmission protocol (or 'air-interface') and a suffix indicating the frequency band of operation. The standardised names for current mobile technologies include:
These names should be used for consistency.
Calculated EME Levels
This table is different in the current EME report. The calculated values of RF EME for the existing transmitting equipment and any proposed changes are presented side-by-side in a single table. Previously two separate tables were used to report the calculated EME levels for 'existing' radio systems and/or 'existing and proposed' radio systems. Originally tables reported 'spot' estimates at prescribed distances from the antenna along the line of maximum EME intensity. Since 2006 the maximum EME level estimated to be found at any azimuth within each of a series of circular bands (annuli) has been reported.
In the original report format, the particular distance used for an estimate may have corresponded to a null in the vertical antenna pattern. This could lead to an EME estimate that, while accurate, was unrepresentative of the surrounding area. It is recommended that 'null fill' (see figure 1) antenna patterns be used to avoid this problem and the use of the maximum value within a circular band will help further. A null fill antenna pattern simply has any significant 'nulls' in the antenna pattern smoothed out or filled in and is therefore conservative when calculating EME levels.
Figure 1. To avoid unrepresentative predictions being made near nulls in the measured antenna pattern (shown dotted), it is recommended that a 'filled-in' pattern (shown as solid line) be used in preparing EME reports.
The calculated EME levels are all quoted as a percentage of the ARPANSA standard, Radiation Protection Standard - Maximum exposure levels to radiofrequency fields - 3kHz to 300GHz. The Standard provides limits that vary with frequency across the range used by mobile phone technologies and EME levels from individual services need to be divided by the appropriate limit before summing. An EME level of 1% of the ARPANSA Standard may represent between 0.045 and 0.10 W/m² depending on the frequency of the service.
Maximum EME level
The azimuth of the expected maximum is no longer provided. Given the typical symmetrical nature of EME levels around a base station, provision of a theoretical azimuth of the maximum could quite often lead to misunderstanding of the EME levels. It is recommended that the carrier provide further clarification if requested. The maximum EME level quoted at the foot of the table will now correspond exactly to one of the entries in the table, and be accompanied by the radial distance at which it is found.
Reference Height Datum
All EME levels, including the maximum value, presented in the Calculated EME Table, are to be calculated at 1.5 m above a flat and level ground at the same effective elevation as the base of the structure supporting the antennas. Where the base station is placed on excavated land that is unrepresentative of the surrounding accessible land, consideration should be given to choosing a more appropriate reference level and adjusting heights of antennas accordingly. The aim is to provide a reliable upper estimate of exposure levels from the base station. Where the surrounding topography is likely to alter the actual or perceived exposure levels, additional estimates should be provided in the Calculated EME levels at other areas of Interest table (see below).
Calculated EME Levels at Other Areas of Interest
The simplifying assumption of level ground used in the estimates above is a practical necessity for routine reports and will usually produce conservative estimates. Where the surrounding land rises in one direction, the associated sector antenna is likely to have reduced down-tilt or even up-tilt to compensate. However, where the ground rises non-uniformly, or it is not accompanied by reductions in down-tilt, actual exposure levels may exceed the estimates based on an assumption of level ground.
The presence of multi-storey buildings close to the antennas may also lead to potential exposures in excess of the predictions of the standard EME report. Depending on distance and height, locations within such buildings should be considered for inclusion in the 'Other Areas of Interest' table. Typically, buildings within 100m of proposed installations are likely candidates for inclusion. So, too, are buildings outside this radius but on direct line-of-sight and close to antenna height.
A scan over the whole height of the candidate buildings should be performed to locate the maximum value of EME. This maximum should be reported where it exceeds the maximum found in the standard 'flat-ground' table, or where it exceeds 1% of the public exposure limit of the ARPANSA Standard. In the interests of privacy, reports should include indications of the height at which the maximum occurs rather than identifying building floors or individual residences.
In some situations, while there may be no increase in actual exposure levels due to rising ground, there may be a perception by even reasonably informed people that EME levels may be raised.
In both cases, the EME report should provide additional estimates for EME levels in representative elevated locations. The exact number of additional estimates provided should depend on the circumstances at each site and the complexity of the topography and proximity of elevated locations.
There are currently no known health effects from exposure to EME from mobile base stations at levels below the general public exposure limit given in the ARPANSA Standard. ARPANSA, however, recognises that some members of the community still have particular concerns and often wish to know the EME levels in particular locations. In recognition of this, ARPANSA encourages inclusion of an estimation of EME levels at additional community locations. It is recommended that any additional locations be based on the community consultation plan or known areas of community concern (see below).
What if no Other Areas of Interest are Identified?
In some cases, after checking:
- Communications Alliance Ltd Industry Code community consultation plan
- topography or buildings near the antennas
- other locations, such as those identified as being of significant previous community concern,
no other areas of interest will have been identified. In this case, the EME Report should include the statement 'No locations identified' in the 'Other Areas of Interest' table, as shown below.
|Additional Locations||Height / Scan
relative to location
|Maximum Cumulative EME Level
All Carriers at this site
Existing and Proposed Equipment
|% of ARPANSA exposure limits|
|No locations identified|
How are specific community sensitive sites selected?
The areas of community interest should be chosen on a site by site basis and are linked to the 'community sensitive locations' identified by the carrier in the community consultation plan required by the Communications Alliance Ltd Industry Code for Mobile Phone base Station Deployment.
In keeping with the spirit of the Code, which promotes transparency and consultation, the following factors should be taken into account:
- Analysis of 'interested and affected' groups as identified in the carrier's community consultation plan.
- Views expressed by the local council.
- Closeness to the antenna of sites widely considered to be of special community interest, such as preschool and childcare facilities.
- For an existing site, previous feedback or objections from this community.
It is to be noted that the ARPANSA Report, including the 'Other Areas of Interest' Table, is a general report undertaken by the Carrier prior to the commencement of consultation with local communities. Any further EME calculations or reports undertaken by the carrier in the course of community consultation or feedback do not form part of the ARPANSA Environmental EME report.