Assessment of human body influence in exposure measurements of electric field in indoor enclosures

Abstract

For Review Personal exposure meters (PEMs) for measuring exposure to electromagnetic fields (EMF) are typically used in epidemiological studies. As it is known, these measurement devices introduce a perturbation of the real EMF exposure levels due to the presence of the human body in its immediate proximity. This paper aims to model the alteration caused by the body shadow effect (BSE) in motion conditions and in indoor enclosures, at the Wi-Fi frequency of 2.4 GHz. For this purpose, simulation techniques based on ray-tracing have been employed, and their results have been verified experimentally. A good agreement exists between simulation and experimental results, in terms of electric field levels, and considering the cumulative distribution function (CDF) of the spatial distribution of amplitude. Kolmogorov–Smirnov (KS) test provides a p-value greater than 0.05, even close to 1. It has been found that the influence of the presence of the human body can be characterized as an angle of shadow that depends on the dimensions of the indoor enclosure. The CDFs show that the electric field (E-field) levels in indoor conditions follow a Lognormal distribution in absence of the human body, and under the influence of the BSE. As a conclusion, the perturbation introduced by the BSE in the PEMs readings cannot be compensated by correction factors: although the mean value is well adjusted, the BSE causes changes in the CDF that require particular attention in order to avoid systematic errors.