After two days of rain in Tokyo I woke up to a thick coating of this yellow stuff all over my car. What looks like a glare between the glass and the body of the car is actually pollen. My first thought was "ewe! Radioactive sludge from Fukushima?" But no, we have been 'assured' and now I am convinced that it was just massive amounts of pollen.
Note: Every year, huge plumes of pollen waft off the cedar trees surrounding the Kanto Plain where Tokyo is located. Not sure where this video is shot, but it illustrates it perfectly: http://youtu.be/Qgdq-RjmJhw The same thing happens in Texas. Look it up on Youtube. Any rain picking this up as it passes over the mountains would release it as yellow rain on the city below. I haven't yet lost my hair. According to the experts there is an abundance of pollen this year because of last year's hot summer.
Note: It is now a week since posting this. I haven't lost my hair. Radiation levels, according to my iphone app are low and Tokyo is sadly devoid of tourists. A lot of people will go out of business because of the natural fear of radiation, but Tokyo is open for business. Don't succumb to fear. Of course be safe and return to Tokyo when things calm down. This is not a Chernobyl by far. Tokyo is 140 miles from the reactor.