ALMOST without exception, scientists and policy makers agree that hybrid vehicles are good for the planet. To a small but insistent group of skeptics, however, there is another, more immediate question: Are hybrids healthy for drivers?
There is a legitimate scientific reason for raising the issue. The flow of electrical current to the motor that moves a hybrid vehicle at low speeds (and assists the gasoline engine on the highway) produces magnetic fields, which some studies have associated with serious health matters, including a possible risk of leukemia among children.
With the batteries and power cables in hybrids often placed close to the driver and passengers, some exposure to electromagnetic fields is unavoidable. Moreover, the exposure will be prolonged — unlike, say, using a hair dryer or electric shaver — for drivers who spend hours each day at the wheel.
Some hybrid owners have actually tested their cars for electromagnetic fields using hand-held meters, and a few say they are alarmed by the results.
Their concern is not without merit; agencies including the National Institutes of Health and the National Cancer Institute acknowledge the potential hazards of long-term exposure to a strong electromagnetic field, or E.M.F., and have done studies on the association of cancer risks with living near high-voltage utility lines.
While Americans live with E.M.F.’s all around — produced by everything from cellphones to electric blankets — there is no broad agreement over what level of exposure constitutes a health hazard, and there is no federal standard that sets allowable exposure levels. Government safety tests do not measure the strength of the fields in vehicles — though Honda and Toyota, the dominant hybrid makers, say their internal checks assure that their cars pose no added risk to occupants.
Researchers with expertise in hybrid-car issues say that while there may not be cause for alarm, neither should the potential health effects be ignored.
“It would be a mistake to jump to conclusions about hybrid E.M.F. dangers, as well as a mistake to outright dismiss the concern,†said Jim Kliesch, a senior engineer for the clean vehicles program at the Union of Concerned Scientists. “Additional research would improve our understanding of the issue.â€
Charges that automobiles expose occupants to strong electromagnetic fields were made even before hybrids became popular. In 2002, a Swedish magazine claimed its tests found that three gasoline-powered Volvo models produced high E.M.F. levels. Volvo countered that the magazine had compared the measurements with stringent standards advanced by a Swedish labor organization, not the more widely accepted criteria established by the International Commission on Non-Ionizing Radiation Protection, a group of independent scientific experts based near Munich.
Much of the discussion over high E.M.F. levels has sprung from hybrid drivers making their own readings. Field-strength detectors are widely available; a common model, the TriField meter, costs about $145 online. But experts and automakers contend that it is not simple for a hybrid owner to make reliable, meaningful E.M.F. measurements.
The concern over high E.M.F. levels in hybrids has come not just from worrisome instrument readings, but also from drivers who say that their hybrids make them ill.
Neysa Linzer, 58, of Bulls Head in Staten Island, bought a new Honda Civic Hybrid in 2007 for the 200 miles a week she drove to visit grocery stores in her merchandising job for a supermarket chain. She said that the car reduced her gasoline use, but there were problems — her blood pressure rose and she fell asleep at the wheel three times, narrowly averting accidents.
“I never had a sleepiness problem before,†Ms. Linzer said, adding that it was her own conclusion, not a doctor’s, that the car was causing the symptoms.
Ms. Linzer asked Honda to provide her with shielding material for protection from the low-frequency fields, but the company declined her request last August, saying that its hybrid cars are “thoroughly evaluated†for E.M.F.’s before going into production. Ms. Linzer’s response was to have the car tested by a person she called her wellness consultant, using a TriField meter.
SNIP
http://www.nytimes.com/2008/04/27/automobiles/27EMF.html?_r=4&pagewanted=1&oref=slogin&oref=sloginInteresting. Over my head, but interesting nonetheless.
