According to the survey of Ministry of Education, Culture, Sports, Science and Technology, in Kawamata machi, Fukushima, where is in the planned evacuation area, leaves of Japanese cedar contain 177,600 Bq/Kg of radioactive cesium.
In Okutama, just west to Tokyo, pollen of Japanese cedar contains 93.8 Bq/Kg,leaves contain 322 Bq/Kg, soil contains 1,381 Bq/Kg.
From their calculation, next year, pollen of over 50,000 Bq/Kg will fly around.
Pollen of Japanese cedar fly for tens of Km, over 300km when it’s on the wind.
Tokyo is only 220km away from Fukushima.
It is highly likely that Tokyo gets hit by the highly contaminated pollen.
I strongly recommend you to leave Tokyo before radioactive pollen hit here.
(Source)