Assessment of electromagnetic dosimetric values from non-ionizing radiofrequency sources in a conventional road vehicle

The use of different wireless communication systems operating in vehicular environments is growing rapidly. Most of these systems have been focused on providing comfort and security, and low consumption wireless technologies offered the possibility of implantation of intra-vehicular networks using ZigBee or Bluetooth, which coexist with long distance communication systems like mobile telephony systems (GSM, UMTS, HSPA, etc.) or location systems such as GPS inside the vehicle. Most works have been written about interferences among wireless systems inside cars, but few speak about dosimetry. These last studies have been usually done theoretically using simulation tools, calculating electric field and hence, Specific Absorption Rate values. In this work, a dosimetric evaluation inside a conventional car is performed in order to assess the compatibility with current exposure limits. The electric field produced by three wireless communication systems (ZigBee, GSM and UMTS) has been estimated using an in-house developed 3D ray launching code, and then measurements have been taken by means of a spectrum analyzer and a dosimeter. The ICNIRP has developed the most authoritative guidelines in order to regulate the exposure conditions to electromagnetic sources. Although the obtained values are below the ICNIRP limits, nowadays no definitive knowledge has been obtained about the effect of long-term low-level exposure to wireless technologies, so this 3D ray launching algorithm can aid in an adequate assessment of human exposure to nonionizing radiofrequency fields, obtaining the estimations of the E-field (see Fig. 1), specific regions of higher amplitudes or hot spots identification.