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Introduction A radiofrequency (RF) survey was conducted in response to a request from Helen Doyle, Manager, Health Protection Division, York Region Community and Health Services Department, at the Al Palladini Community Centre and the Pierre Berton Library on May 23, 24 and 25, 2012. The reason for the survey was to address concerns regarding a radio communication tower which is located approximately 150 metres from the back entrance of the Al Palladini Community Centre. The measurements were done in accordance with Health Canadas RF exposure guidelines, Limits of Human Exposure to Radiofrequency Electromagnetic Energy in the Frequency Range from 3 kHz to 300 GHz, known as Safety Code 6 (SC6) (Health Canada, 2009a). The term RF (radiofrequency) refers to part of the electromagnetic spectrum that is used for radio communications purposes. Figure 1 below shows the RF bands, together with the ranges of frequencies commonly used for various other applications, including those used for telecommunications, industry and in medicine. Figure1: Spectrum Frequency
Frequencies LF: low MF: medium HF: high VHF: very high UHF: ultra high SHF: super high EHF: extremely high
Source: Health Protection Agency (2012) Ontario Agency for Health Protection and Promotion Page 1
Safety Code 6 The Safety Code 6 (SC6) standard specifies limits of human exposure to RF fields (in the range 3 kHz to 300 GHz) to prevent adverse health effects. The standard is applicable whenever any member of the general public may be exposed to RF fields. The limits given are for exposure averaged over a 6 minute period. Frequency range measured In this survey, the electromagnetic field within the frequency range of 9 KHz 6 GHz was sampled and recorded. Probes used Because the frequency range covered was so large, three RF probes were used: Three axis Isotropic Response Magnetic-field antenna 3581/02 ( 9 KHz to 27 MHz) Three axis Isotropic Response Electrical-field antenna 3501/03 (27 MHz to 450MHz) Three axis Isotropic Response Electrical-field antenna 3502/01 (450 MHz to 6 GHz)
RF instrument used Narda Selective Radiation Meter (SRM 3006) Calibration: Last calibrated on March 6, 2012 A non-conducting wooden support pole was used to mount the probe and a wooden pedestal was used to mount the RF survey meter (see Appendix A). The measurements were taken above the ground, at eye level (1.75 metres).
Locations Measured Measurement of the radiofrequency electromagnetic field intensity levels were taken at six different locations around the site (see Appendix B). Five measurements (Site 1-4, 6) were taken outside where the public has general access, and one was taken inside (Site 5). Site 1: In front of Al Palladini Community Centre, in the handicap parking lot, about 240 metres from the communication tower Site 2: In the back parking lot, about 80 metres from the communication tower Site 3: Pierre Berton Library, 10 metres from front, 105 metres from the communication tower Site 4: Hill between Emily Carr Secondary School and the Al Palladini Community Centre, about 100 metres from the communication tower Site 5: Al Palladini Community Centre, Meeting Room 1 Site 6: Path to rear entrance of Al Palladini Community Centre, about 100 metres from the communication tower
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Method All readings taken were as a percentage of SC6 for the general population limit measured over a six minute period. Both the cumulative total maximum value and the six minute time-averaging RF intensity values were logged for each RF probe. For each Site, total combined values for the RF spectrum measured (9 kHz to 6GHz) were calculated by adding results from the 3 RF probes (Health Canada, 2009b). The following locations were measured on May 23 (Day 1), 24 (Day 2) or May 25 (Day 3): Site 1: Day 1 and Day 2 Site 2: Day 1 and Day 2 Site 3: Day 1 and Day 2 Site 4: Day 2 Site 5: Day 1 and Day 2 (420MHz to 6GHz only). Site 6: Day 3 Results Both the highest cumulative maximum and 6 minute time-averaging RF levels, relative to SC6 limits, for each site measured are listed in Table 1 (detailed results can be found in Appendix C). The cumulative 6 minute time-averaging value represents a more realistic sample of actual exposure as opposed to the cumulative maximum values, which represent a less realistic but higher exposure scenario. Almost all (98% on average) of the RF energy levels found at each location lay between 420 MHz and 6 GHz. For a visual representation of the frequency spectrum [9 kHz to 27 MHz; 27 MHz to 420MHz to 6 GHz] please see Appendix D. For the locations surveyed, the highest cumulative time-averaging SC6 levels of all measurable signals (9 kHz to 6 GHz) was 0.0789%, or about 1267 times below the recommended SC6 limit (cumulative maximum value was 0.13544%, or about 738 times below the recommended SC6 limit). This level was recorded in front of the Pierre Berton Library, about 100 metres from the communication tower (Site 3). The second highest cumulative time-averaging SC6 level was recorded in the back parking lot of the Al Palladini Community Centre, about 80 metres from the communication tower (Site 2). Its level was 0.07779%, or about 1286 times below the recommended SC6 limit (cumulative maximum value was 0.17512%, or about 571 times below the recommended SC6 limit).
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Table 1: SC6 levels at measured locations (where more than one measurement was performed, the highest value was used for comparison and analysis purposes).
MAXIMUM LOCATION % OF SC6 GENERAL PUBLIC LIMIT NUMBER OF TIMES BELOW SC6 TIME AVERAGING 6 MINUTE TIMEAVERAGED (% OF SC6 GENERAL PUBLIC LIMIT) NUMBER OF TIMES BELOW SC6
Site 1: In Front of Al Palladini Community Centre, front parking lot, about 240 metres from the communication tower Site 2: In the back parking lot of Al Palladini Community Centre, about 80 metres from the communication tower Site 3: Pierre Berton Library, 10 metres from front entrance, 105 metres from the communication tower Site 4: Hill between Emily Carr Secondary School and the Al Palladini Community Centre, about 100 metres from the communication tower Site 5: Al Palladini Community Centre, Meeting Room 1 (this measurement was performed for interest and is not included in the average) Site 6: Path to rear entrance of Al Palladini Community Centre, about 100 metres from the cellular tower AVERAGE
0.04543
2,201
0.02680
3,731
0.17512
571
0.07779
1,286
0.13544
738
0.07890
1,267
0.05531
1,808
0.03492
2,864
0.02000
5,000
0.01200
8,333
0.10755
930
0.06238
1,603
0.10377
964
0.056158
1,781
The cumulative time-averaging SC6 level at the path to the rear entrance of the Al Palladini Community Centre, about 100 metres from the cellular tower (Site 6), was 0.06238%, or about 1600 times below the recommended limit (cumulative maximum value was 0.10755%, or about 929 times below the recommended SC6 limit). The cumulative time-averaging SC6 level on the hill between Emily Carr Secondary School and the Al Palladini Community Centre, about 100 metres from the cellular tower (Site 4), was 0.03492%, or about 2864 times below the recommended limit (cumulative maximum value was 0.05531%, or about 1807 times below the recommended SC6 limit). The highest cumulative time-averaging SC6 level in front of the Al Palladini Community Centre, about 240 metres from the cellular tower (Site 1) was 0.02680%,
Ontario Agency for Health Protection and Promotion Page 4
or about 3731 times below the recommended limit (cumulative maximum value was 0.04543%, or about 2201 times below the recommended SC6 limit). The major contributor in the back parking lot, on the hill, in front of the library and at the rear entrance path was dominated by an older mobile cellular phone frequency (806 MHz 890MHz). In the front parking lot, the dominant contributor was also a cell phone frequency, but in the range of 1850 MHz to 2000 MHz (see Appendix E for greater details). To put the RF exposure levels found here in context, levels measured by Industry Canada in the City of Toronto are compared (Industry Canada, 2007) below. o The highest cumulative 6 minute average level found by Industry Canada was at the Metro Hall grounds. The level was 2.11%, or 47 times less than the SC6 limit. o The second highest average level found was at the Spadina Avenue Parkette. The level was 0.44%, or 227 times less than the SC6 limit. o Industry Canada noted that if both the Metro Hall and Spadina Parkette measurements were to be removed from the calculation, because of their proximity to the clustered broadcast facilities in the core of Toronto, the average SC6 percentage for commercial areas would be 0.0556%, or 1798 times less than the SC6 limit. The average SC6 percentage in our survey was almost exactly the same 0.056158%, or 1,781 times less than the SC6 limit. Please note the inside measurement in Meeting Room 1 was not included in the calculating the overall average. As a matter of interest, measurements were performed in Meeting Room 1, Al Palladini Community Centre (Site 5) using Probe 1 (420 to 6 GHz). The use of only Probe 1 is justified because almost all (98% on average) of the RF energy for the 6 minute time-averaging radiofrequency levels found at each location lay between 420 MHz and 6 GHz. The highest cumulative 6 minute time-averaging SC6 level recorded was 0.01200%, or 8333 times below the recommended SC6 limit (cumulative maximum value was 0.02000%, or about 5000 below the recommended SC6 limit).
Conclusion The recorded data indicated that the cumulative 6 minute time-averaging SC6 levels for all sites are only a small fraction of the SC6 requirements for the general public and therefore comply by a wide margin.
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REFERENCES Health Canada (2009a). Limits of Human Exposure to Radiofrequency Electromagnetic Energy in the Frequency Range from 3 kHz to 300 GHz, Safety Code 6 (2009) Health Canada (2009b). Technical Guide for Interpretation and Compliance Assessment of Health Canada's Radiofrequency Exposure Guidelines Nguyen B., Mohabeer S., Lai V. and Lander E (2000). Evaluation of Electromagnetic Field Intensity in the City of Toronto, Report for Industry Canada, Spectrum Management, Ontario Regional Engineering, Canada, June 2002. Lai V (2007). Measurement and Analysis of Radiofrequency Electromagnetic Field. Intensity in the Vicinity of the Union Street Water Tower, Simcoe, Report for Industry Canada, Spectrum Management, Ontario Regional Engineering, Canada, September 2007 Health Protection Agency (April 2012). Health Effects from Radio Frequency Electromagnetic Fields.
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Appendix A
Instrument set up
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Appendix B
Sites
Pierre Berton Library
Site 3 Site 5
AL Palladini Community Center
Site 4
Site 1: In Front of Al Palladini Community Centre in the handicap parking lot, about 240 metres from the communication tower Site 2: In the back parking lot of Al Palladini Community Centre, about 80 metres from the communication tower Site 3: Pierre Berton Library, 10 metres from the front, 105 metres from the communication tower Site 4: Hill between Emily Carr Secondary School and the Al Palladini Community Centre, about 100 metres from the communication tower Site 5: Al Palladini Community Centre, Meeting Room 1 Site 6: Path to rear entrance of Al Palladini Community Centre, about 100 metres from the communication tower
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Site 2: In the back parking lot, about 80 meters from the cellular tower 23-May-12 Number of times below SC6 256,410 136,986 575 571 6 minute Time- Number of averaged (% of times below SC6) SC6 Time 0.00020 0.00059 0.07700 0.07779 500,000 169,492 1,299 1,286 11:59:00 AM 11:49:00 AM 12:13:00 PM 24-May-12 6 minute TimeNumber of Number of times averaged (% times below SC6 of SC6) below SC6 285,714 12,346 746 702 0.00019 0.00064 0.06700 0.06783 526,316 156,250 1,493 1,474
Site 3: : Pierre Berton Library, 10 meters from front, 105 meters from the cellular tower 23-May-12 Number of times below SC6 238,095 116,279 943 932 6 minute Time- Number of averaged (% of times below SC6) SC6 Time 0.00019 0.00069 0.06000 0.06088 526,316 144,928 1,667 1,643 12:39:00 PM 12:48:00 PM 12:29:00 PM 24-May-12 6 minute TimeNumber of Number of times averaged (% times below SC6 of SC6) below SC6 294,118 111,111 745 738 0.00019 0.00071 0.07800 0.07890 526,316 140,845 1,282 1,267
Site 4: Hill between Emily Carr Secondary School and the Al Palladine Community Centre, about 100 meters from the cellular tower 24-May-12 Maxium (% of SC6) 0.00038 0.00093 0.05400 0.05531 Number of times below SC6 263,158 107,527 1,852 1,808 6 minute Time- Number of averaged (% of times below SC6) SC6 0.00020 0.00072 0.03400 0.03492 500,000 138,889 2,941 2,864
Site 5: Al Palladine Community centre, Meeting Room 1 23-May-12 Number of times below SC6 5,000 6 minute Time- Number of averaged (% of times below SC6) SC6 Time 0.01200 8,333 2:55:00 PM 24-May-12 6 minute TimeNumber of Number of times averaged (% times below SC6 of SC6) below SC6 7,143 0.00888 11,261
Time 2:54:00 PM
Site 6: Path to rear entrance, about 100 meters from the cellular tower 25-May-12 Number of times below SC6 714,286 243,902 935 930 6 minute Time- Number of averaged (% of times below SC6) SC6 0.00019 0.00019 0.06200 0.06238 526,316 526,316 1,613 1,603
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Appendix D
Spectrum 9 kHz to 27 MHz
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Appendix E Major Contribution Source Contribution Table 6 minute Average Fmax (MHz) % 890.0000 0.0700 890.0000 0.0500 890.0000 890.0000 2000.0000 2000.0000 0.0530 0.0500 0.0200 0.0057
Location Back parking lot Hill Front of the library Rear entrance path Front parking lot Meeting Room 1
Source Cellular Phone Cellular Phone Cellular Phone Cellular Phone Cellular Phone Cellular Phone
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