Mobile phone masts, which have been blamed for illnesses ranging from headaches to cancer, do not cause short-term health effects, according to a British study published on July 25.
Independent scientists at the University of Essex said they had conducted one of the largest studies into whether symptoms such as tension, anxiety and tiredness could be linked to phone masts beaming conventional 2G (second-generation) and higher-frequency 3G (third-generation) signals.
The team of scientists tested 44 people who had already reported symptoms or sensitivity to mobile phone technology and 114 people who had not reported any health effects at a specially designed laboratory.
According to the study, the heart rate, blood pressure and skin conductance - which is considered a good measure of physiological response to environmental stress - of participants was not affected by whether the mast was on or off.
"It is clear that sensitive individuals are suffering real symptoms and often have a poor quality of life," said Professor Elaine Fox, the principal investigator in the three-year study.
"It is now important to determine what other factors could be causing these symptoms, so appropriate research studies and treatment strategies can be developed," she added.
Scientists around the world have been monitoring the effects of radio-frequency (RF) fields, which are generated by devices such as mobile phones, television remote controls and wireless security systems, on human health for around 60 years.
David Coggon, professor of occupational and environmental medicine at the University of Southampton, said the latest study was consistent with other research that suggests so-called "electro-sensitivity" in some people was psychological rather than a toxic effect of radio waves in most cases.
Nevertheless, a rising tide of public concern about possible health risks related to mobile phone technology has triggered protests in Britain at plans by mobile phone companies to site masts near schools or hospitals.
The World Health Organisation (WHO) has said that reviews conducted so far have shown that exposure to low-level radio frequencies does not produce any known adverse health effects. But is has also said further research is needed.
Meanwhile, Vodafone Group Plc, the world's largest mobile phone company outside China, said on July 24 that it was among a large group of companies being sued in the United States over health concerns related to mobile phone use.