Safety Guidelines of Mobile Phone Base Stations and Radio Frequency Radiation

A typical mobile phone base station consists of radio equipment rack with transmitters and receivers, and directional antennas. The antennas are usually mounted on rooftops of tall buildings like HDB flats, condominiums and commercial/industrial buildings or on monopoles, that provide the required height for the intended service coverage. The MNOs have installed mobile phone base stations island-wide to cater for users' demand and must meet IMDA's quality of service standards. Each base station emits certain amount of RF radiation as part of its service coverage, which may range between 500m and 2km in radius. This is also known as the radio network coverage distance.

The purpose of each base station is to connect mobile phone users to the mobile network to make calls or access the Internet. 

Electromagnetic field ("EMF") radiation refers to the waves of electric and magnetic energy that are transmitted through the air at the speed of light. Different types of EMF radiation are categorised by their wavelengths or frequencies. RF is the portion of EMF radiation with frequencies ranging from 3 kilohertz ("kHz") to 300 Gigahertz ("GHz"). In radio-communication systems, RF is used to carry audio, video and data information such as voice and video call, short message, e-mail, data file, etc. from one point (antenna) to another (radio receiver).

The figure below shows a snapshot of the electromagnetic spectrum and examples at different frequencies in Singapore.

RF radiation is a form of non-ionising radiation and is different from X-rays and Gamma rays which are a form of ionising radiation.

Non-ionising radiation moves atoms in a molecule around or causes them to vibrate (which would generate heat) but does not have enough energy to remove electrons from atoms and break chemical bonds in our cells^#.

Ionising radiation possesses enough energy to knock electrons out of atoms and poses a health risk as it can potentially damage tissue and DNA in genes. Long-term exposure to ionising radiation at high levels can harm people’s health^#.

Reference:

^# NEA. Radiofrequency (RF) Radiation. https://www.nea.gov.sg/our-services/radiation-safety/radiofrequency-radiation/background

RF radiation is a form of non-ionising radiation and is different from X-rays and Gamma rays which are a form of ionising radiation. The WHO has found no convincing scientific evidence of adverse health effects in populations or individuals who are exposed to very low levels of RF radiation, over varying periods of time.

The WHO indicated in its fact sheet entitled Electromagnetic fields and public health: mobile phones (issued on 8 October 2014) that: "A large number of studies have been performed over the last two decades to assess whether mobile phones pose a potential health risk. To date, no adverse health effects have been established as being caused by mobile phone use." For the full text of the fact sheet, please refer to the WHO website here.

Mobile communication has become an integral part of everyday life, where consumers expect comprehensive and high-quality mobile coverage. MNOs deploy base stations in suitable locations (both in-building and outdoor) in order to meet the stringent mobile coverage quality of service standards imposed by IMDA. 

Having a mobile phone base station installation nearby will improve weak coverage spots in the vicinity and mobile connectivity experience for the residents. With a nearer mobile phone base station, a mobile phone will operate at lower RF power when connecting to the mobile phone base station during calls and/or surfing the Internet. 

The ICNIRP guidelines is widely used as a benchmark by many countries, like Australia, Germany, Japan, Norway, South Korea, and Sweden. The consensus of many expert reviews is that there are no established health risks when RF-EMF levels comply with the limits in the ICNIRP guidelines.

From the ICNIRP guidelines for RF radiation, the reference levels for general public exposure to RF radiation depend on the frequency of the RF radiation. The reference levels for common sources of RF radiation ranges from 4.5 to 10 W/m2 for frequencies related to mobile phones and mobile phone base stations. These reference level limits are similar to the common source of RF radiation for frequencies related to Wi-Fi routers and microwave ovens.

IMDA and NEA have jointly conducted measurements in HDB flats, Condominium and Commercial/Industrial Buildings. Results of measurements showed that the RF radiation levels near mobile phone base stations have complied with the safety guidelines set by ICNIRP. Measurements also showed that the ambient RF radiation levels in Singapore are typically thousands of times below the limits in the ICNIRP guidelines.

For more information on the guidelines for RF radiation, please refer to the NEA website here.

IMDA considers the public concerns over the effects of RF radiation from mobile phone base station, as the licensing authority. We have therefore specified technical specifications, such as limiting the emission power of base stations, so that they operate within the standards developed by the ICNIRP. In addition, IMDA works closely with NEA to ensure RF radiation from mobile phone base stations installed island-wide are within the safety guidelines specified by ICNIRP. The current RF radiation levels in publicly accessible areas around mobile phone base stations are far below the ICNIRP exposure limits and are therefore safe.

For more information on RF radiation, please refer to the NEA website here.