Mammoth knows more about natural radiation than almost any other place in the country.
We sit atop radioactive rock, we ski so high that we are exposed to 70 percent more radiation than people living at sea level.
But calls are still coming into the county health department, people worrying about radiation coming across the ocean on a plume, in the water, through our food.
The bottom line, according to Dr. Rick Johnson, the county’s public health officer, is not only are fears about Japan’s radiation reaching us in large enough doses to be dangerous over-rated (barring any massive, new problems with the reactors), the true danger here is the one we already live with and many do far too little about – the brilliant, high-country sun.
“What Eastside residents really have to worry about, and many don’t, is the natural radiation from the sun,” Johnson said.
Yes, the sun. Mammoth had the highest UV readings in the country when solar radiation measurements were taken in a 2003 study, according to a recent New York Times article.
“Scientists studying sun safety took multiple readings of ultraviolet radiation at 32 high-altitude ski areas in western North America,” the December 2010 article states.
The readings were taken in March 2003.
“Readings were generally highest in high-altitude resorts in Arizona and New Mexico, but the highest UV rating – 10 UV index units – was taken at Mammoth Mountain in California.
“That rating is “just as intense as being smack-dab in the middle of the sun at Jones Beach (New York) in June,” says Peter A. Andersen, a professor of health communications at San Diego State University.”
Andersen, whose work focuses on skin cancer research, spoke to the Mammoth Times Thursday and detailed why the UV rays here in Mammoth are so comparatively high.
“Number one, it’s your relatively high altitude, compared to other resorts,” he said.
“This reading was taken at the top of Dave’s Run, above 10,000 feet (Dave’s Run starts at 11, 053 feet).
For every 1,000 feet of elevation, you get another six percent to eight percent increase in UV exposure, so you have 70 percent more UV exposure here than you would at sea level.”
“Second, it’s because Mammoth Lakes is so far south, relative to the other ski resorts (the farther south in altitude until the equator, the more direct the sun’s rays are, with the rays being the most direct at the equator).”
The third factor is the clean air in Mammoth.
“Mammoth’s air is very clean, due to the lack of humidity and because there is so much clean air blown in off the Pacific,” Andersen said.
He noted the irony that pollution actually protects from skin cancer, due to the particulates in the air, while at the same time, increasing lung cancer.
Another factor Andersen noted is the fact that Mammoth gets so much snow, and is relatively free of tree cover. Those two facts also increase exposure to the sun.
Andersen said the study also revealed something disturbing. While skin cancer is one of the most preventable cancers, by wearing sunscreen and avoiding direct sun, only about 50 percent of the people in the study did it.
But it was worse two decades ago.
“In the 90s, it was only 23 percent,” he said.
The study also showed that more people took proper precautions regarding the sun on warmer days, thinking there is a correlation between warmth and sun exposure.
There isn’t, except insofar as the fact that later in the year, the sun’s rays are more direct and direct light is usually warmer light.
The danger comes not from the heat, but the direct nature of the light.
So, a cold, sunny day in the middle of January with less direct light than spring, but at high elevations and on a mountain completely covered in snow requires sunscreen just as much as a hot day in March, he said.
Even a cloudy day on Mammoth Mountain is dangerous.
“It’s a case that less sun is always better,” Andersen, who has already battled skin cancer several times, said.
And there’s more.
Eastern Sierra residents are also more exposed to another source of naturally occurring radiation, the gases from uranium-bearing granite rocks, which occur here in larger amounts than almost anywhere else in the country.
Granite is the backbone of most of the High Sierra peaks outside your window and granite contains uranium, which, as it decays over time, gives off a gas called radon.
“Southern Mono County and northern Inyo County are well known areas for radon gas seepage,” Dr. Johnson said.
Radon is not the sexy, high profile kind of radiation you hear about on the evening news, but it can be a real issue for local residents, as it gets trapped in garages and basements and under homes.
A simple, cheap test from the health department can test your home for radon gas, although the cost of fixing the problem can be significantly more expensive.
But all that said, is the Eastside really that dangerous, due to radiation?
No, says Dr. Johnson.
“About 17 percent of the naturally occurring radiation we are exposed to comes from the sun,” said Johnson.
“Twenty percent comes from the earth’s crust (radon, etc.). Another 13 percent comes from the food we eat, fruits and vegetables, which concentrate radiation.”
The rest is in water.
“This might all sound frightening,” Johnson said, “but even with Mammoth’s increased risks due to the sun, it’s nothing compared to the man-made sources of radiation that more and more people expose themselves to: CT scans, even smoking.”
A CT scan exposes you to 100 times as much radiation as a chest X-ray.
(With cigarettes, the radiation from the chemicals in the cigarettes is concentrated in the smoke, making smoking even more dangerous than many believe, he said.)
All these things and more, including riding in an airplane, expose residents to far more radiation than experts believe could be released from Japan’s ailing reactors and reach this country.
So, what is worth worrying about, and what can you do about it?
“Sure Mammoth residents, by choosing to live here, expose themselves to two or three times the amount of solar radiation than other people would,” Johnson said.
“But it’s still not very much, given the low percentage of natural radiation that comes from the sun overall. And, it can be mitigated, with sunscreen and staying out of the sun.”
So while more than half of all cancers are skin cancer (according to Andersen) skin cancer is also very easy to prevent.
It’s far more dangerous to do the things we do every day: drive to work, cross the street, smoke, eat too much. Those are the four biggest killers of Americans, Johnson said.
Worth some thought, don’t you think?