Introduction
Mobile phones are now an integral part of modern telecommunications in many places including Hong Kong. The mobile phone technology relies on the transmission of radiofrequency (RF) signal which generates electromagnetic fields (EMF).
Are there any health effects?
Unlike ionizing radiation such as X-rays and nuclear radiation, radiofrequency electromagnetic fields generated by mobile phone technology are a type of non-ionizing radiation. Simply put, non-ionizing radiation has lower energy and is insufficient to change the chemical properties of substances. It cannot cause harm by breaking chemical bonds in the human body.
At present, the well-established health effect of RF EMF exposure is mainly related to heating. RF EMF from mobile phone may be absorbed into the body and generates small amount of heat. As the body's normal thermoregulatory processes can carry this heat away, there is no substantiated evidence to show adverse health effects from normal use of mobile phone.
The International Agency for Research on Cancer (IARC) under the World Health Organization launched an international study (INTERPHONE Study) in Year 2000 to determine whether mobile phone use increases the risk of brain cancer. In 2010, the Study Report concluded that "Overall, no increased risk of brain cancer was observed with the use of mobile phone. There were suggestions of an increased risk at the long-term heavy use of mobile phone, but biases and errors prevent a causal interpretation. The possible effects of long-term heavy use of mobile phone require further investigation". After reviewing the evidence critically in 2011, the IARC has classified RF EMF as "possibly carcinogenic to humans" (Group 2B). Generally speaking, there is less than sufficient evidence in experimental animals and only limited evidence in humans showing that agents classified under Group 2B are carcinogenic. As a matter of fact, the proven health risk is far lower than that of asbestos, smoking, second-hand smoking, nicotine and ionizing radiation, etc. Further investigation of long-term, heavy use of mobile phone and brain cancer risk is merited.
Minimizing the risk
While conclusive evidence of adverse health effects from use of mobile phone awaits the results of further investigation, some precautionary measures could be adopted to reduce exposure to RF EMF, such as limiting the length of mobile phone calls and using "hands-free" devices that keep the mobile phone further away. Some members of the public may be particularly concerned that children and adolescents may be more vulnerable to the effects of radiofrequency electromagnetic fields, because this technology has been available to them from their early years. As a precautionary measure, the use of mobile phone by children for non-essential calls should be minimized.