So we read news that the radiation level in Tokyo following the nuclear plant explosions at Fukushima (explosion at nuclear reactor 1 occurred on Saturday, 12 March, the day after the earthquake-tsunami catastrophe; and a second explosion at nuclear reactor 3 occurred on 13 March, Sunday), has risen 20 times, but still at a safe level. The next questions that come to mind but are not expanded on by these journalists are: What is this level? What is the safe level? At what level is it not safe?
The exact units of measurement vary, but light radiation sickness begins at about 50–100 rad (0.5–1 gray (Gy), 0.5–1 Sv, 50–100 rem, 50,000–100,000 mrem). The SI unit of radiation dose equivalent is the sievert, 1/1000 of a rem (1 mrem = 0.01 mSv). — Wikipedia
At a facility in Shinjuku Ward, a maximum level of 0.809 microsievert was detected at around 10am, but the hourly level went down to 0.151 microsievert after 11am (16 March, Wednesday). These figures compare with 0.035 to 0.038 microsievert detected Monday (14 March). Fifty (50) microsieverts is absorbed when one takes a chest X-ray. — Japan Times
So when journalists say that the radiation level in Tokyo has increased 20 times but is not detrimental to your health, the “not detrimental to your health” phrase doesn’t sound believable because the “20 times” sounds “detrimental” to your health. Except for the article in the Japan Times published Wednesday, all other articles on Tuesday using this phrase (that the “radiation levels has increased 20 times but is not detrimental to your health”), do not mention numbers and figures to substantiate their affirmation, only that stressful number “20 times.”
Little does the unsuspecting public know that 20 times of the fraction .04 mSv is .80 mSv. Based on the above maximum level, 80.9 mrem, computed as 0.01x mrem=.809 mSv, is significantly less than the 50,000 mrem, the level where radiation sickness occurs.
In conclusion, when journalists of dubious intelligence report that the radiation levels have risen 20 times without substantiating numbers or figures or calculations, they are SENSATIONALISING the news, causing a panic situation that affects business very badly and consequently, our financial future.