For instance, I was walking across the Brooklyn Bridge when the second plane hit the World Trade Center on 9/11. Now, no matter how often I come across statistics about flying being safer than driving, there's a part of me, deep down, that doesn't really believe it.
Still, it's helpful to remain rational. So hat's off to NPR's Richard Knox for doing the math and offering a reality check after some dire warnings from the World Health Organization about food contaminated by radiation emitted from the Fukushima Dai-ichi power plant in Japan.
Here's Knox's bottom line assessment, based on an interview with Peter Caracappa, a health physicist at Renssealaer Polytechnic Institute in Troy, N.Y. who has been calculating various radiation risks on specific foods, such as milk, spinach and drinking water: "...the risk of ingesting even the most highly contaminated Japanese foodstuffs reported so far is very, very small."
"The long and the short of it is that we're not going to be able to detect any statistically significant change in the cancer rate for anyone as a result of the events in Japan," Caracappa told Shots.
The Spinach Risk:
Caracappa figures someone would need to eat 41 pounds of that Hitachi spinach to reach the nuclear power plant worker's annual exposure limit. "That's a significant amount of spinach," he allows.
But what about cancer? That's probably what most people worry about when they hear about radioactivity in food. Well, it takes 20 million becquerels to yield a Sievert's worth of exposure; remember, that's what it takes to increase a lifetime cancer risk by 4 percent.
That translates to 820 pounds of spinach – more than two pounds a day for a year.
The Milk Risk:
Well, nobody eats spinach every day. But many people drink milk every day. And one lot of milk sampled from the town of Kawamata, 29 miles from the power plant, reportedly contained 1,510 becquerels of radiation per kilogram.
To reach the radiation dose limit for a power plant worker, you'd need to drink 2,922 eight-ounce glasses of milk. To raise your lifetime cancer risk by 4 percent, you'd have to drain more than 58,000 glasses of milk. That would take you 160 years, if you drank one 8-ounce glass a day.
This program aired on March 22, 2011. The audio for this program is not available.