## 2 Materials and Methods
### Selected Urban and Suburban Environments  
The measurements were conducted in four regions--two urban and two suburban--each covering approximately 4-7 km\({}^{2}\) in the regions of Attica and Central Macedonia, Greece. Table 1 provides an overview of these regions, which are subdivided into the noted municipalities and include various points of interest (POIs) such as parks, bus stations, university campuses, and shopping malls, areas that typically have higher public concentrations. Within each region, a grid was established by appropriately spacing measurement points, considering the existence of POIs, thus creating a grid with 100 measurement points at ground level. As an example, Figure 1 illustrates the Attica urban region with measurement points, POIs, locations of base station antennas (BSAs), small cell antennas (SCAs) and NOEF broadband and selective stations. The initial placement of each point was predetermined; however, adjustments may have been necessary if (a) physical access to a point was obstructed by obstacles or private properties or (b) closer proximity to POIs was required. \begin{table}
\begin{tabular}{c c c c c c} \hline \hline \multirow{2}{*}{**Region**} & \multirow{2}{*}{**Municipalities**} & \multirow{2}{*}{**Surface (km\({}^{2}\))**} & \multirow{2}{*}{**Number of Residents (2021 Census)**} & \multirow{2}{*}{**Base Station Antenna (BSA) + Small Cell Antenna (SCA) Density (Antennas/km\({}^{2}\)) *} & \multirow{2}{*}{**Number of 5G**} \\  & & & & & \\ \hline A. Attica, urban & Athens & 39.0 & 637,798 & \(\sim\)120 & 31 \\ \hline B. Central & \multirow{2}{*}{ \begin{tabular}{c} Thessaloniki \\ urban \\ \end{tabular}  } & \multirow{2}{*}{19.3} & \multirow{2}{*}{319,045} & \multirow{2}{*}{\(\sim\)55} & \multirow{2}{*}{15} \\  & & & & \\ \hline C. Attica, suburban & Agia Paraskevi & 7.9 & 62,147 & & \\ \cline{1-1} \cline{3-5} \cline{7-7 In the Results section, we performed a Kruskal-Wallis test to compare the measurement results across the various environments and regions. This non-parametric statistical method assesses whether there are statistically significant differences between two or more groups. Consistent with prior research, we anticipated significant differences in values between urban and suburban environments, as observed in previous studies [13]. Regarding cellular networks, BS density typically correlates with population density. Suburban areas, characterized by lower populations, more sparse development, and shorter buildings \begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Region** & **Municipalities** & **Surface** & **Number of** & **Base Station Antenna** & \\  & **(km2)** & **Residents** & **(BSA) + Small Cell** & **Number of 5G** \\  & & **(km2)** & **Antenna (SCA) Density** & **BS (3.5 GHz)** ** \\  & & & **(Antennas/km2)* & \\ \hline D. Central & & & & \\ Macedonia, & & & & \\ suburban & & & & \\ \hline  & & & & \\  & & & & \\ \end{tabular} Note: * based on the official registry for mobile communication installations in Greece ([[https://keras.eett.gr/](https://keras.eett.gr/)]([https://keras.eett.gr/](https://keras.eett.gr/))), operated by the Hellenic Telecommunications and Post Commission (EETT); ** the number of 5G base stations (BSs) refers specifically to those operating in the 5G FR1 band during the measurement period, as confirmed through official communication with all three national mobile network providers following the completion of the measurements.  
\end{table} 
Table 1: _Cont._  
Figure 1: Selected measurement points, POIs, locations of base station antennas (BSAs), small cell antennas (SCAs) and NOEF broadband and selective stations in the urban region of Attica (Athens city center) over an area of 2 \(\times\) 2 km2. The BSA locations shown, along with information about their technical characteristics, are based on the data publicly available through the official EETT database [12]. compared to urban areas, likely have fewer BS. This, in turn, contributes to lower EMF values in these regions.