Dear EarthTalk: What's the latest research on the question of whether cell phone use causes cancer? -- William Thigpen, via e-mail
Cell phones have only been in widespread use for a couple of decades, which is far too short a time for us to know conclusively whether or not using them could cause cancer. Research thus far appears to indicate that most of us have little if anything to worry about.
According to the federally funded National Cancer Institute, the low-frequency electromagnetic radiation that cell phones give off when we hold them up to our heads is "non-ionizing," meaning it cannot cause significant human tissue heating or body temperature increases that could lead to direct damage to cellular DNA. By contrast, X-rays consist of high-frequency ionizing electromagnetic radiation and can lead to the kind of cellular damage resulting in cancer. Nonetheless, some cell phone users and researchers still worry about our cell phone usage, given how much we now use them and how little we know about their potential long-term effects.
The reason the issue keeps coming up is that some initial studies in Europe, where cell phone usage caught on a decade before the U.S., showed links between some forms of tumors and heavy cell phone usage. As a result, researchers teamed up to do a more definitive study, called the "Interphone" study, across 13 countries between 2000 and 2004. The results, published in May 2010 in the peer-reviewed International Journal of Epidemiology, indicated no increased risk of developing two of the most common types of brain tumors, glioma and meningioma, from typical everyday cell phone usage. Study participants who reported spending the most time on their phones showed a slightly increased risk of developing gliomas, but researchers considered this finding inconclusive due to factors such as recall bias, whereby participants with brain tumors may have simply remembered past cell phone use differently from healthy respondents.
Researchers looking to get past the relatively short timing window and the recall bias issues of the Interphone study recently launched a longer term study, dubbed COSMOS (short for Cohort Study on Mobile Communications), in Europe. Some 250,000 cell phone users between the ages of 18 and 69 and located in Britain, Finland, the Netherlands, Sweden and Denmark will participate by allowing researchers to track their cell phone usage and health over three decades. According to an April 22, 2010, article in Reuters, the study will factor in the use of hands-free devices and how people carry their phones and will also be on the lookout for links to neurological diseases such as Parkinson's and Alzheimer's.
There are some precautions you can take to minimize whatever risk may exist. The Federal Communications Commission (FCC) suggests reserving the use of cell phones for shorter conversations, or for times when a conventional phone isn't available. Also, using a hands-free device places more distance between the phone and your head, significantly reducing the amount of radiation exposure. If the fact that many states require hands-free devices for using a cell phone while driving isn't enough to make you go out and spend the extra money on such an accessory, maybe the cancer risk, perceived or real, will.
More InformationFact box
Dear EarthTalk: In his recent State of the Union Address, President Obama called for a million electric vehicles on American roads by 2015. How likely is it that we'll attain that goal? -- Jerry Mitlitski, Salem, ORE.
"We can break our dependence on oil ... and become the first country to have 1 million electric vehicles on the road by 2015," President Obama said in his January 2011 State of the Union address. "The future is ours to win."
It's difficult to say how likely such an arbitrary goal might be, but green leaders and others are optimistic. The waiting list for the new electric Nissan Leaf, rolling off the factory floor as we speak, is some 20,000 Americans long. The auto industry expects similar demand for other new electric and plug-in hybrid cars hitting U.S. roads this year and next from General Motors, Ford, Toyota, Mitsubishi and others.
Of course, the Obama administration realizes that attaining such a goal will be impossible without help from the federal government. To that end, consumers and businesses can get tax credits worth up to $7,500 on the purchase of each new electric vehicle (EV). The feds have also committed $2.4 billion for research and development into improving EV batteries, and another $115 million for the installation of EV charging infrastructure in 16 different metro areas around the country -- not to mention some $300 million in clean cities grants to dozens of American communities working to reduce petroleum use, and the $25 billion being doled out to help U.S. auto makers retool. So much federal involvement has helped spur state governments and private industry to make significant investments in the EV sector as well.
But even with all this funding, a million EVs on the road by 2015 may still be just a pipe dream. James Sweeney of Stanford University's Precourt Energy Efficiency Center calls the plan "very aggressive." He reasonED that it took over a decade for hybrids -- which "did not require any difference in infrastructure and had as great a range as conventional vehicles, neither of which is likely to be the case with electric vehicles" -- to capture three percent of the U.S. passenger car and light truck market. EVs would have to achieve the same market share in just four years if Obama's goal is to be realized. "Even with a large subsidy, it would be very hard to move to such a large market share that quickly," Sweeney concludeD.
The Electrification Coalition, an organization of pro-EV business leaders from companies including Nissan, Federal Express, Coda Automotive and Coulomb Technologies, would take issue with that conclusion, however. The group's November 2009 study, dubbed the Electrification Roadmap, predicted that as many as 14 million EVs could be on American roads by 2020 if lawmakers create "electrification ecosystems" in several major U.S. cities simultaneously. If the group is anywhere near the mark, reaching Obama's goal of a million EVs by 2015 should be a no-brainer. The group also says that EVs could account for as many as 75 percent of all miles driven by light duty vehicles in the U.S. by 2040.
Now if only we could clean up our supply of electricity too, then we really might be onto something good for the planet.
Send your environmental questions to: EarthTalk, c/o E -- The Environmental Magazine, P.O. Box 5098, Westport, CT 06881; earthtalk@