Everyone on this planet is exposed to some naturally occuring background radiation every day. About
2.5mSv/year. However, some areas have higher levels (Ramsar Iran at
250mSv/yr ) of background and others less, also an individuals activities (frequent mountain climbing, air travel, spaceman) can change this number.
An additional
20mSv/yr is considered an acceptable safe dose for a Nuclear Energy Worker.
At the most recent published maximum dose rates that I could find in the Fukushima area (about
.003mSv/hour in exclusion zone, near but NOT at the plant site) measured last April, you would reach
20mSv in about
278 days if you lived there full time during that period. Dose rates in Tokyo and Supporo, or even in other areas of Fukushima prefecture are way lower. Dose rates in Soeul Korea are higher than Tokyo. New York has the same rate as Tokyo. I could be wrong though, the site was in Japanese.
So, depends on how close to Fukushima and for how long. Possibly the direction of wind as well as direction of current could be a factor. Are they coming from the Fukushima area??
I hope this puts this subject into some perspective. Personally, I would not be too concerned about kiting in Asia (or most places for that matter) due to radiation.