– Moms Turn Activists in Japanese Crisis (Wall Street Journal, June 16, 2011):
Airborne radiation levels are within their average prequake range in most of Japan and at elevated but unalarming levels in some communities in Fukushima prefecture and the areas immediately surrounding it. The big exception is the city of Fukushima, 37 miles from the stricken plant, which on Wednesday had airborne radiation levels of about 1.5 microsieverts per hour, 30 to 40 times the usual average.
For the general public, the government sets a limit of one millisievert a year for exposure to nuclear plants or other man-made sources of radiation. The average person world-wide receives radiation totaling 2.4 millisieverts per year, or 2,400 microsieverts, from all sources— from natural sources to radon, but not from exposure from X-rays and airplane flights, according to Japanese officials.
Akiko Matsuoka, a mother of two girls, lives in Kashiwa, which has higher-than-normal airborne radiation levels of around 0.3 to 0.4 microsieverts per hour, according to city officials, one of the highest in the Tokyo metropolitan region. “I was very concerned about the situation and I didn’t have anyone to talk to,” she said. “I found people online. They wanted to create an online petition; I volunteered to do it.”