Assessment of Non-ionizing Radiation Exposure Levels in Selected Commercial and Residential Areas of Nairobi City

Abstract

Assessment of non-ionizing radiation (NIR) exposure levels in both urban and rural areas is necessary owing to the vast utilization of wireless communication and associated devices that utilize radio-frequency energies. Excessive NIR exposure has been linked to negative human health effects such as nerve stimulation and changes in cell membrane permeability. The International Commission for Non-Ionizing Radiation Protection (ICNIRP) provides NIR exposure guidelines for both occupational workers and the general public. The city of Nairobi is the headquarters for many telecommunication companies in Kenya, and it is densely populated. Thus, many base transmission stations (BTS) have been installed by various telecommunication providers. However, there has been no scientific study undertaken so far to assess the NIR exposure levels. This work provides a preliminary study of NIR exposure levels to the general public in Nairobi. Electromagnetic frequency fields (EMF) were measured systematically using a spectrum analyzer (Spectran HF6065) connected to an antenna (HyperLOG 7060) in the city’s Central Business District (CBD) and in three densely populated areas at the outskirts of the CBD. The observations were assessed and compared with the ICNIRP standards. The median values for the total exposure to EMF in Nairobi CBD and residential areas were 0.90 +/ 0.30 V/m and 0.81+/-0.25 V/m respectively, while the total exposure values to EMF range 0.14 V/m and 3.67 V/m. The GSM900 was found to contribute higher exposure to NIR than the other frequency bands (LTE700, LTE800, GSM1800, UMTS2100 and LTE2600) considered in this work. Using the Kriging technique, a spatial map showing the distribution of the EMF measurements was generated showing areas with high probability of EMF exceeding 2 V/m in the CBD. The results obtained showed that the exposure to EMF in all the areas assessed was below the limits provided by the ICNIRP guidelines. The findings of this study can be used to establish a baseline for future NIR exposure studies.