Spatial and Temporal Mapping of Radiofrequency Fields

Abstract

The objective of this study was to explore the spatial and temporal distribution of radiofrequency (RF) fields due to wireless device transmissions in areas of maximum human exposure in Halifax, Nova Scotia. These RF fields are subject to a public perceived risk of adverse health effects, and results from many epidemiological studies are largely inconclusive. Previous analyses of the effects of non-ionizing radiation on health are limited because the intensity of radiation depends on other covariates such as spatial orientation and time. This exploratory study aimed to demonstrate the feasibility of mapping RF radiation to reduce such spatial and temporal limitations of future epidemiological studies. Using a selective radiation spectral analyzer, we measured radiofrequency fields between 80Hz-3GHz in busy areas along Spring Garden Road and its side streets. We selected for the ranges of frequencies used by wireless devices to transmit and receive information, specifically those of cell phone base stations and wireless local area networks. We accounted for the time-varying elements of the radiofrequency fields by randomly selecting sampling periods from the 24 hours in a day. We combined RF field strength data and per-second location coordinates from a Global Positioning System (GPS) and displayed the spatial variation on ArcGIS maps for each time period sampled. Temporal variation was found to be statistically significant. Aggregated field strengths from the cell phone and WLAN RF bands did not exceed the recommended exposure limits in Health Canada's Safety Code 6.