## 5 Conclusions  
In this research study case performed in Vilnius (the largest urban community in Lithuania) an original investigation methodology for RF EMF assessment was proposed, taking into consideration all presented technical aspects, which could be of interest to specialists in mobile telephony base station antennas and public health, respectively. The measurements of the RF electric field strength and RF EMF power density conducted in the near- and far-fields of the mobile telephony base station antennas, lead to the following conclusions:  
1. In the near-field (up to a distance of 30 m), the values of the strength of the RF electric field radiated by the antennas varied from 7 to 195 V/m. In the near-field, the RF EMR intensity parameters exceeded the allowable norm (ICNIRP Guidelines);
2. The RF EMF power density values of the high effective radiation power emitted into the environment by the mobile antenna up to a distance of 500 m amount to approximately 0.01%-10% of the allowable level (10 \(\upmu\)W/cm\({}^{2}\)). This is influenced by the effective radiation power of the mobile antenna, the downtilt angle, and the height of the antenna above the earth's surface;
3. The high effective radiation power of the directional mobile antenna revealed that the antenna with a height of 30 m has small values of RF EMF power density, reaching about 0.01%-0.04% of the allowable level (10 \(\upmu\)W/cm\({}^{2}\));
4. The RF EMF power density values of the mobile antenna with a height of 14 m at a distance of 50 m reached 0.98 \(\upmu\)W/cm\({}^{2}\), but decreased significantly at greater distances (100 m or more), and amounted to only 0.005%-0.01% compared with the ICNIRP allowable values;
5. The RF EMF power density values on the ground surface at a distance of 50-200 m from the mobile antenna were very small and varied from 0.01 to 0.98 \(\upmu\)W/cm\({}^{2}\), which is 100 to 10 times lower than the allowable level (10 \(\upmu\)W/cm\({}^{2}\));
6. The RF EMF power density values of mobile antennas with high effective radiation power and a height of up to 30 m are significantly higher and reach 1 \(\upmu\)W/cm\({}^{2}\). This influences the direction diagrams of mobile antennas in the vertical plane. In this position, where the basic diagram's slip reaches the earth's surface, topical maxima are formed. Depending on the antenna's height and electrical and mechanical downtilt, the maxima of the power density of the RF EMF can form at a distance of 100-300 m;
7. The RF EMF power density values of mobile telephony base station antennas in the air at ground level increase farther from the antenna. The highest values can be observed at the point where the main antenna radiation zone reaches the earth's surface; farther away, these decline.  
The field measurements conducted were financed by European Higher Education Area, including Lithuania and Poland. The costs of publication in open access were also included.  
[PERSON] performed the experimental measurements of electromagnetic radiations; [PERSON], [PERSON], [PERSON], [PERSON] and [PERSON] analyzed the obtained data; [PERSON] contributed with their competences to all mechanical design and technical support during the experimental part, including construction and maintenance of high antennas used for different type of GSM system; [PERSON], was involved as specialist on Buildings and Civil Engineering, dealing with design of the anchorage for supporting antenna on the roof of high buildings in order to support a wind speed of 100 km/h; [PERSON], conceived and designed the experiments, coordinated the activities for each the proposed objectives of this study.  
The authors declare no conflict of interest. The founding sponsors had no role in the design of the study; in the collection, analyses, or interpretation of data; in the writing of the manuscript, and in the decision to publish the results.