Hybrid Watchdog:  Hybrids and Electromagnetic Fields (EMFs)

Electromagnetic fields (EMFs) are invisible forces created whenever you have electricity or an electric charge. Televisions, power lines, cell phones, electric motors and stereo speakers are examples of products that generate EMFs. These fields also occur naturally, in static electricity on a sweater, for example, or in the clouds before a thunderstorm.  On April 27, the New York Times published an article on the EMF/hybrid subject noting the uncertainties on this issue, but there is a far larger picture than that painted in that piece.

Based on a review of the literature, there is no conclusive evidence to date that EMF poses a health threat at the low levels found in all automobiles today, including hybrids. A 2007 World Health Organization (www.who.int/peh-emf), report indicated that “current evidence does not confirm the existence of any health consequences from exposure to low level electromagnetic fields. However, some gaps in knowledge about biological effects exist and need further research.”

Hybrids do create EMFs.  One might naturally think that those fields would be larger than in standard cars because of the added batteries and electric motor.  However, a 1999 study by the Department of Transportation indicates that the low frequency EMF in electric vehicles is nearly the same as those in conventional vehicles and a thousand times below European Union standards (there are no standards in effect in the US). 

While it might be a little counterintuitive, the conclusions make sense when you consider the design of hybrids.  Hybrid vehicles use electricity to turn the wheels, however, the wiring in which the electricity passes is shielded, limiting the reach of any EMF (if they did not shield the wires, your stereo and cell phone would not work well due to the interference). In addition, the wiring is usually placed outside the passenger compartment. Furthermore, almost all of the EMF generated in a hybrid vehicle is static—meaning it does not vibrate. It’s the effect EMF vibration or frequency has on the human body that has been the focus on most health concerns. There is some higher frequency current and EMF associated with the hybrid electric system, but again, most of the health concerns are focused on low frequency.

Measuring EMFs accurately is tricky in itself.  The process needs to be conducted in an isolated chamber, because devices inside the vehicle, such as stereo speakers, and outside, such as power lines, can inflate the reading.  Indeed, the 1999 DOT study found that one of the dominant sources of EMF in gasoline and electric vehicles came from the residual magnetic field in the rotating tires. And not all EMF meters are created equal. You need sensitive instrumentation that can measure the field strength at each frequency, separately. So, there are plenty of sources that can cause elevated readings, especially in hand-held meters.

Given the national health benefits of hybrids, reducing smog-forming and global warming pollution, the overall energy benefits, and the savings to drivers at the pump, the EMF issue, while deserving of more study, should not hold back consumers or automakers from putting more hybrid vehicles on the road.