## 2 Materials and Methods  
### Virtual Measurements  
When workers are at some distance from the EMF source, they receive EMF exposure at \"far-field conditions\", which may justify the exposure evaluation being performed based on the E-field measurements [30]. In the case of \"near-field conditions\" which exist in proximity to the EMF sources, the evaluating of hazards from exposure is based on Specific Absorption Rate (SAR) being a measure of thermal effects, which denotes how much energy per unit time and unit mass is absorbed by the tissue. The use of multi-location distributed RF EMF exposure evaluation was studied using virtual measurements mimicking a series of measurements in various far-field exposure scenarios through relevant numerical simulations. The investigations covered models of 24 exposure scenarios corresponding to typical exposure conditions in the environment, characterized by various directions of homogeneous RF EMF propagation with regard to the vertical axis of the human body model (Figure 3). The models of exposure scenarios represent various positions of the person against the EMF source through diverged RF EMF propagation: (i) transverse--from right to left side and E-field vertical; (ii) sagittal--from front to back and E-field vertical; (iii) vertical--from top to bottom and E-field horizontal perpendicular to the frontal cross-section; (iv) vertical--from top to bottom and E-field horizontal perpendicular to the sagittal cross-section. The simulations were repeated for typical frequencies of EMF emitted from different wireless radio communications systems: 100, 400, 700, 1000, 1800, 2600 and 3600 MHz, which cause usually far-field exposure in the urban environment as shown at Figure 1.  
In the simulations, a constant value of 10 V/m of the E-field strength amplitude of continuous wave (CW) RF EMF was set at the edge of the analyzed area, from the boundary of space where the electromagnetic wave was radiated. It means, that the exposure scenarios showed the EMF distribution near the worker's body exposed to RF EMF at the workplace, which would be evaluated at a level of 10 V/m of unperturbed EMF (i.e., in the absence of the worker at the workplace under inspection). On the basis of the results of relevant calculations regarding RF EMF spatial distribution, the E-field strength was determined at seven locations near the exposed body model: 5-55 mm away from the front (F), back (B), left and right sides (L and R) and top of the body model (H), for horizontal cross-sections at heights: 1.08 m for the waist (W) from the front and back; 1.34 m for the chest (C) from the front and back; 1.39 m for the right and left arms (A); and 1.82 cm for the head (H) (Figure 4). The locations of the analysed measurement points were selected to take into account the locations of PEMs which may be considered for the work environment measurements. As mentioned, for the measurements taken with research projects on public exposure in mind, PEMs were located in different placeson body without limitations on where. However, in work environments potential PEM locations have to respect significant limitations--they cannot hinder the normal activities of the exposed worker and cannot cause any safety hazards in the work environment. For example, a location at the side of the waist may hinder the free hanging of the arms, while a location on the shoulder may increase the body's outline and cause related discomfort or hazards for workers. It was assumed that the applied locations of point-assessment of the E-field in the numerical simulations would mimic the results of real measurements from wearable  
Figure 4: Location of E-field point assessment on waist (W), arms (A), chest (C) and head (H); view on the front, back and left side of the Duke body model.