Summary of Review by Cambridge Environmental Inc. of Newton Tower Materials

Memorandum

To:             J. David Naparstek, Commissioner, Newton Health Department
From:         John M. Osepchuk and Peter A. Valberg
Subject:     Summary of our Review of Newton Tower Materials
Date:         December 6, 1998

        

OVERALL CONCLUSIONS:

We have reviewed the series of reports by Don Haes on measurements and calculations of Radiofrequency fields in the vicinity of the ATS tower at 1165 Chestnut Street, in Newton Upper Falls. We have also conducted our independent sets of measurements using a broad-band Holaday 3004 survey probe as well as spectrum analyzer measurements, using a linear monopole antenna. We have confirmed that most of the energy in the environment is from existing FM sources on the tower. Contributions from other nearby towers is minor.

Our measurements agree roughly with theoretical predictions, to the degree that would be expected. The latter show a peak of ~3% of the 200µW/cm2 maximum permissible public exposure (MPE), or 6.0 µW/cm2. We have measured values from 0 to 8.6 µW/cm2, i.e., peaking at about 4.6% of MPE. This is reasonable agreement, recognizing the random spatial variability of RF patterns as modified by the complex topography. We note also that the measurements of Bob Watkins, of the Commonwealth Public Health Department, are in the same rough range.

Measurements by Don Haes have yielded generally less than 1% MPE readings, or < 2 µW/cm2, except for the data at unit #13 at 1175 Chestnut Street, where up to 1.5% MPE, or 3 µW/cm2, was measured. The difference of about 2 to 1 between the data of Haes and Watkins and ourselves is not unreasonable, considering calibration errors, measurement errors, and the variability in the selection of spot for measurements. It may be that Haes selected spots more randomly or did better averaging, while Watkins and ourselves tended only to record localized peak fields.

We are confident that the existing and proposed towers will exhibit field levels on the ground far below the MPEs specified by the Federal Communications Commission (FCC) and the Commonwealth of Massachusetts, and well below 10% of the MPE. Most of the energy is now and will in the future be located in the FM band.

We note that there are localized "hot spots" of energy close to guy wires, although they are still significantly below the MPE. These have not been accessible to us and we assume they will not be accessible to the general public. We have not studied the radio-wave environment on tower property.

We are confident that the existing and proposed towers will exhibit field levels on the ground far below the MPEs specified by the Federal Communications Commission (FCC) and the Commonwealth of Massachusetts, and well below 10% of the MPE. Most of the energy is now and will in the future be located in the FM band.

We note that there are localized "hot spots" of energy close to guy wires, although they are still significantly below the MPE. These have not been accessible to us and we assume they will not be accessible to the general public. We have not studied the radio-wave environment on tower property.

Our review of the work of Don Haes and our independent measurements and calculations all support the conclusion that the Radiofrequency environment around the existing ATS tower and also the proposed ATS tower. with its expanded number of sources, both are in compliance with the FCC Rules. (Report and Order, FCC-326, August 1, 1996; First Memorandum and Order, FCC-487, December 23, 1996; Second Memorandum Opinion and Order and Notice of Proposed Rulemaking, FCC 97-303; August 25, 1997.)

We are in the process of a more complete review of the literature supplied to us in support of the thesis that the FCC Rules are inadequate. We will complete our analysis and respond to these materials. Based on our knowledge of the literature, however, we believe it is very unlikely that the supplied literature will provide convincing reasons for abandoning our confidence in existing standards adopted by responsible authorities all over the world. Overall, we do not see significant problems with Don Haes’ calculations or measurements. Overall, we both endorse the validity of the exposure standards for the general public that are presented in Don Haes’ reports.

SUPPORTING MATERIAL (arranged in the order of the agreed-upon tasks

(1) We have reviewed the following reports provided by Don Haes, and we have spoken with Don Haes whenever we encountered an aspect of the analysis we did not clearly understand. The list below identifies the various reports, gives a short summary of each Don Haes report, and gives our comments on that report.

(a) September 9, 1998, Evaluation of Compliance, Existing Newton Tower. 57 pp.Calculating the contribution all sources on the ATS tower together gives a maximum impact of 2.87% MPE at a distance of 575 feet from the base of the tower. RF field measurements (August 28, 1998) were obtained at locations at a distance of 20 cm (8 inches) from guy wires, and the maximum spatial average readings are reported as 13.5% MPE.

(b) September 15, 1998, Evaluation of Compliance, Proposed Newton Tower. 82 pp.Conclusion is that overall theoretical maximum exposure will decrease by 30% (2.87% MPE decreasing to 2.02% MPE).

COMMENTS ON (a) AND (b): Antenna attenuation factors (the "Relative Field Factor") were not part of the reports we received, but were provided to us by Don Haes upon request. These data give antenna transmitting energy a function of elevation angle and permit calculation of ground levels per formulas endorsed by the FCC (Report OET-65), including worst-case assumptions such as calculation at a height of 6 feet above ground, with inclusion of a substantial ground reflection contribution.

We have checked the theoretical calculations in the reports by Don Haes, dated Sept. 9 and Sept. 15, 1998. There are some errors in the text that Mr. Haes has acknowledged -- e.g. the antenna designations for existing sources in report (b) are erroneous and there is some ambiguity about the location of WCRB. With the appropriate corrections, we have checked and verified all the theoretical calculations except one and have found them to be accurate when the correct designation of antenna is used. The only exception is the calculation for the proposed three new UHF NTSC TV stations, which has the assigned antenna type, ALP-32L3-HSWR, per the report. The available data for the ALP32 antenna yield calculations that do not agree with the calculations published in Table XVII, pp. 51 - 53 of report (b). Don Haes reports that a different antenna was actually selected. He is attempting to locate the gain data for that antenna. We expect this discrepancy to be resolved soon.

We conclude that the theoretical calculations are accurate and appropriate for predicting rough spatial patterns of energy in the environment in the vicinity of the tower. For the existing tower (Table IV in the first report) the calculations show a peak of ~ 2.8% MPE at around 500 feet distance from the tower and mostly from the FM stations. This is confirmed by our empirical spectral analysis data.

The calculations for the proposed tower show a maximum from existing sources of ~1.99% MPE at 2000 feet--almost all from FM sources. The newer antennas reduce the field close to the tower at the expense of moderate increase further out. Note that the new predicted maximum of 1.9% MPE is less than the predicted maximum of 2.8% for the existing tower. (See Table XXV in report (b)).

All the new sources on the proposed tower are predicted to produce a maximum field of < 0.3% MPE at around 250 feet. The new sources will therefore be a minor contribution to the total Radiofrequency environment. (See Table XXVI in report (b)).

The predictions, thus, are for significant decrease (2- to 8-fold) in maximum fields on the ground close to the tower (0-800 ft), with the location of maximum fields moving from 500 feet out to 2000 feet out. The explanation for these changes is increased height of the tower plus the use of new antennas on the proposed tower with greater directivity or reduced downward radiation. Aside from some difficulty in associating specific field factors with specific antennas, these calculations are overall correct.

(c) September 10, 1998, Tutorial explanation of technical terms in 9/9/98 report. 4 pp. COMMENT: ONLY EDITORIAL

(d) September 17, 1998, Summary of Evaluations. 2 pp. COMMENT: ONLY EDITORIAL

(e) September 10, 1998, Physical measurements of RF and 60-Hz EMF. 10 pp.

RF measurements were made on August 28, 1998. Tower base maximum was 9.4% MPE. Maximum of all other measurements was 0.8% MPE. Maximum of guy wire measurements was 13.5% MPE. The maximum power-line EMF reading was 5.2 mG

COMMENT: "EMF" is not relevant to the antenna tower operations. Failure to detect RF power with the H-field meter probably reflects lack of sensitivity in this meter rather than absence of RF H-fields. E-field meter results are acceptable.

(f) September 15, 1998, Supplement to 9/10/98 report on RF measurements. 8 pp. Measurements (Sept. 14, 1998) were obtained in response to a request from the community. 16 locations were measured, all less than 0.7% MPE.

COMMENT: H-field meter results reflect a lack of instrumental sensitivity. E-field meter results judged acceptable.

(g) October 28, 1998, Supplemental Measurement for Apt. #13, 1175 Chestnut Street, Newton, MA. Maximum level measured was 1.55% MPE, with an indication that the maximum contributor is TV Channel 2 (not on the ATS tower).

COMMENT: Our measurements are in general agreement with those of Don Haes, although our estimate of the contribution of Channel 2 is not as large as suggested by Haes’ report.

(f) November 17, 1998, Theoretical Evaluation Supplement for combined impact of four towers within 3 miles of the ATS tower. Maximum impact from cumulative sources does not exceed 0.8 % MPE.

COMMENT: These calculations appear to be in general agreement with our spectral analysis of the vicinity of the Newton Tower.

(2) We have performed confirmatory broadband RF measurements. Broadband RF measurements were made on Friday, November 27, 1998, from 12:00 noon to 4:00 pm. Additional measurements were made on November 30 and December 3 as part of the spectral analysis task. The broadband RF instrument used was the Holaday HI-3004 Broadband Isotropic Electric Field Strength Meter, S/N 87152, calibrated on September 28, 1998. The readout of the instrument is an analog meter calibrated in "volts per meter" (V/m). The "V/m" readings can be converted into power levels (microwatts per square centimeter, µW/cm2) when measurements are made at a distance from the source many wavelengths away, which was always the case for the measurements reported here. The High-Sensitivity Electric (HSE) field strength probe, in association with the HI-3004 field strength meter, provided the following sensitivity ranges over the frequency band from ½ to 1,500 megahertz (MHz):

Instrumental sensitivity ranges of the HI-3004:

- 1 V/m (0 - 0.26 µW/cm2)

• 0 - 3 V/m (0 - 2.4 µW/cm2)

• 0 - 10 V/m (0 - 26 µW/cm2)

• 0 - 30 V/m (0 - 240 µW/cm2)

The specified location was surveyed over a horizontal area of about plus or minus 10 yards, and over such an area, the meter reading typically would vary about a factor of two. The reading reported below is the higher end of this range. The sensor probe was held at about 3 to 5 feet above ground level, which generally resulted in maximum readings. The street locations listed below yielded the RF levels indicated below. The "%MPE" values are calculated on the assumption that the most conservative public exposure limit applies, namely, 200 µW/cm2. To the extent that frequencies outside the 3 - 300 MHz range were likely measured, this calculation may be a significant overestimate of "% MPE."

V/m µW/cm2 "% MPE"
(% of 200 µW/cm2)

(1) Pette Street (off Elliot) playground at end 1.90 0.9 0.5

(2) Intersection of Pette, High, Elliot, Oak         1.45 0.6 0.3

(3) Pennsylvania and Oak    2.05 1.1 0.6

(4) Pennsylvania and Ohio                         2.75 2.0 1.0

(5) Pennsylvania and Indiana 3.15 2.6 1.3

(6) Indiana and Indiana Court 4.40 5.1 2.6

(7) Pennsylvania and Chestnut 3.40 3.1 1.6

(8) Officer Bobby Braceland Playground 3.75 3.7 1.9

(9) Pennsylvania and Keefe 3.90 4.0 2.0

(10) Chestnut Grove, space in front of Unit #11 4.85 6.2 3.1

(11) Chestnut Grove, space in front of Unit #13 5.50 8.0 4.0

(11) End of Sweet Street, within parking lot 5.70 8.6 4.3(12) Saco and Butts 4.70 5.9 3.0(13) Oak Street & Bay Colony RR tracks 4.90 6.4 3.2

(14) Development, Saco Street end (Oak Park) 3.85 3.9 2.0

The overall conclusion to be drawn is that all RF power levels encountered were within the sensitivity range of the probe, and were well below the RF levels permissible for general public exposure, a conclusion that is consistent with the measured RF levels that Don Haes reported.

(3) We have performed a (narrowband) spectral analysis (SA) of RF levels in the vicinity of the Chestnut Grove condominiums (1175 Chestnut Street). On November 30 and December 3, 1998, we conducted spectrum analyzer (SA) measurements of the RF environments at condominiums #7 and #13 , respectively, at 1175 Chestnut Street in Newton. About 10 spectra were recorded at each location, using scans of 0 to 1 GHz, 25 to 125 MHz, and 100 to 300 MHz. Attached are 4 samples of these spectra.

The equipment used was:
Hewlett-Packard Spectrum Analyzer 8569B
Hewlett-Packard Plotter 7090A
Coil-loaded whip antenna of 3 foot length plus connectors, cables, and coaxial attenuators.

Measurement of spectra at different points and under different conditions of antenna location and orientation (polarization) reveals the complexity of the electromagnetic (EM) environment in which the approximately 10 FM signals, 10 TV signals and comparable number of low-power wireless signals are present. Each frequency will exhibit a spatial pattern that is different to patterns at other frequencies, with no correlation expected among the separate patterns. In the same vein, we note that the SA data provide no simple correlation with broad-band probe data, but do provide a complementary view of the complex distribution of RF signals. Both spot measurements with broad-band probes at different locations and a variety of SA records provide sets of data encompassing statistical variations.

We assume that spectral levels at different points and polarizations are distributed in a log normal fashion. Thus, it is reasonable to average log values to get a measure of probable field levels. We have 8 sets of data for 25 - 125 MHz, 4 sets for 0 - 1 GHz, and 2 sets for 100 - 300 MHz. The calculated averages are tabulated below.

Table 1: Average Signal Strength in 0 - 1 GHz Spectra

Channel Number 2 4 5 FM 7 19 25 38 44 56

(unresolved)

Levels (dBm) -24 -31 -31 -10 -30 -39 -31 -40 -49 -38

Table 2: Average Signal Strength in 25 - 125 MHz Spectra

Channels/Stations

2 4 5 wbor wbos wjmn wsjz wbmx _?_ wcrb wods wror wmjx

Levels (dBm)

-22 -33 -35 -40 -23 -17 ----- -20 -16 -21 -14 -52 -53

Table 3: Average Signal Strength in 100 - 300 MHz Spectra

Channel 7: approx. -22 dBm

We conclude that the major, by far, portion of the RF energy in these environments is from the FM sources, most of which are identified as being mounted on the ATS tower at 1165 Chestnut Street. We conclude that the contributions from nearby towers, i.e., the VHF and UHF TV signals, while significant, are minor compared to the FM signal strengths.

Thus, because the RF levels (in toto) near the ATS tower are well below the FCC compliance limits, it is also unlikely that RF levels at points midway between towers will approach compliance limits. Note that this is reasonable if one recognizes that levels on the ground decrease rapidly with distance from the tower when close to the tower, but out further the decrease is slower. This is borne out in theoretical calculations for the existing and proposed sources on the ATS tower.

(4) Our narrative summary of the conclusions from the above tasks is that the available evidence supports the conclusion that both the present and proposed Newton ATS tower at 1165 Chestnut Street is compliant with applicable RF standards. We believe that current scientific evidence supports the protective nature of the RF standards against adverse health effects in general, and adverse neurological and behavioral effects in particular. Periodic RF monitoring at several locations might well serve the purpose of allaying any anxiety about just what quantity of RF energy is present. Finally, if ATS is willing to guarantee that RF levels at public locations are a specified fraction of the applicable standard (e.g., 10%), this again might be effective at allaying anxiety. However, there is no established evidence that such a limitation will be "more safe" than the current standards.

(5) Our initial review of the articles submitted by the opponents to the ATS tower does not suggest that the current standards are flawed. Scientific data on any particular subject is constantly being generated, published, and reviewed. Publication per se does not signify that the results are accepted by the scientific community as valid, and in fact, publication is the beginning rather than the end of the review of the reported results by the general scientific community. The essential test of scientific validity is a finding that is reproduced in other laboratories and by other scientists. The available RF data have been reviewed recently (1998) by groups such as the World Health Organization and the International Commission on Non-Ionizing Radiation Protection. These "blue-ribbon" reviews remain consistent with the earlier reviews by the National Radiation Protection Board, Environmental Protection Agency, and others, in failing to find reliable evidence for "non-thermal," adverse biological effects at very low RF levels.

Peter A. Valberg, Ph.D.
John M. Osepchuk, Ph.D.

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