A majority of Americans use their mobile phones to access the Internet, and a growing number use their handsets as their primary online device says a survey by Pew Research Center. The survey found 3 out of every 5 mobile phone owners now use their phone to go online. And because nearly all Americans now own a cell phone, this means that half regularly use their phones to surf the internet. The proportion of mobile phone owners who use their phone to go online has doubled since 2009, Pew found. That may raise public health concerns related to exposure to cell phone radiation emissions says Environmental Health Trust (EHT), a group promoting safer phone use especially for non-adult users and for pregnant users.