of changes between successive one-minute records were 51 and
26 V/m.
While these observations appear generally consistent with
recent survey measurements of these parameters near ac lines
[6]–[8], they provide information about frequency and duration
of potential exposure that survey measurements, that are focused
on maximum or short-term average values, do not. Based on
this study, ac transmission lines appear to have a minor impact
on potential long-term exposure to space charge (ions and/or
charged aerosols) beyond the ROW.
ACKNOWLEDGMENT
The electric-field and ion data analyzed here were the product
of a dedicated project team that included R. Layman, J. Hornig,
L. Dickson, and W. Hoppel. Without their talents, skills, and
perseverance in the long New Hampshire winters these analyses
would not have been possible. The authors gratefully acknowledge
the contributions of J. Dudman to data management, data
analysis, and production of this manuscript. The assistance and
cooperation of C. H. Moser and his staff at National Grid are
greatly appreciated.