While media around the world continue to present the Fukushima nuclear crisis as an Armageddon moment for Japan and the world, Japanese media are going out and taking measurements of radiation levels all around the Kanto region. Because I have not been able to find this type of information easily in English I have translated a radiation map of Japan into English and created a clear overview for you here.
Before we jump into the map, I’d like to direct you to an article and a blog shared with me by two Americans living in Sendai, near the epicenter of the Tohoku Earthquake and where the tsunami struck. For those still feeling panicked by media reports, please read what Greg Harbin and Aimee McFarlane have to say. If you are willing to believe first-hand accounts, this will completely change your perspective on the situation.
Now, on to the map, I was able to get new readings for Monday, March 21, 2011 in Japanese from Yomiuri Shimbun. I have updated the infographic below with these new readings.
You can click the map above to open a larger view.
You can still access my map with the March 18 readings if you would like to compare. Note that some labels differ because Yomiuri Shimbun is using some city names instead of prefecture names on the March 21 map or took readings at different nearby locations.
The readings for March 21 show small increases in some areas and small decreases in others. Overall the levels are slightly higher but are still far below levels that could affect human health. Levels near Fukushima have dropped considerably, down from 10.90 microsieverts on Friday, March 18, to 7.47 microsieverts on Monday, March 21. This is at the perimeter of the 60km evacuation area. Outside of this area the highest reading found was 0.340 microsieverts at Mito. Apart from this there are a few readings around the 0.1 microsievert level. Tokyo came in at 0.125 microsieverts on March 21. Most others are closer to the 0.05 microsievert level. None of these are of concern to human health.
The measurements on this map ware taken by the Yomiuri Shimbun, one of Japanese largest newspapers. I have seen separate readings from Asahi TV’s Hodo. Their readings were slightly different than these, but essentially the same. The point being that various private organizations are taking their own readings, so do not fall for those who claim the Japanese government or TEPCO is hiding or understating risks.
I should also point out that all of the measurements on this map are in microsieverts (μSv). A sieviert is a measure of the biological effect of radiation. 1,000 microsieverts = 1 millisievert. We all receive around 2 millisieverts (mSv) per year just from the natural background radiation.
To this end I have also put together some tables showing annual natural radiation exposures, annual exposures from common activities, and single dose exposures from medical procedures. In these tables I show the difference between these levels and current Tokyo levels, and the amount of time Tokyoites would need to be exposed to current radiation levels in order to equal the exposure from these natural sources and activities.
I have updated these tables to reflect the radiation level recorded for Tokyo on March 21.
All of the measurements in these tables are given in millisieverts (mSv).
Source: Table data from various studies and journals as cited here. Column for time it would take Tokyo levels to equal the annual or single dosage is based on the level of 0.125μSv/hour for Tokyo as found in the Yomiuri measurements. That’s 0.125 x 24 hours x 365 days which totals 1,095 microsieverts for the year or 1.095 millisieverts.
My purpose is not to deny the seriousness of the Fukushima situation or the fact that radiation levels have increased greatly from normal peacetime levels. Rather my purpose is to inject some reality into the overhyped media reports that have people as far away as Pennsylvania buying iodide tablets. Just because an increase is mathematically large doesn’t mean it is harmful.
I live 320km (200 miles) from Fukushima. Pennsylvania is 11,000km away (6,800 miles). If I am exposed to current radiation levels continuously for the next five years I will receive over that period the equivalent of what we all receive from nature’s background radiation each year. Arm yourself with math and scientific facts and then listen to the media reports. You’ll be able to put what is being said into real context.
Dose rates in Tokyo and other cities remain far from levels which would require action—in other words they are not dangerous to human health.
I will just update this post when new readings are available rather than creating new posts for the radiation map each time. That will help avoid the confusion that could be caused by multiple maps.
Japan Radiation Levels (In English)
UPDATED MARCH 22, 2011
While media around the world continue to present the Fukushima nuclear crisis as an Armageddon moment for Japan and the world, Japanese media are going out and taking measurements of radiation levels all around the Kanto region. Because I have not been able to find this type of information easily in English I have translated a radiation map of Japan into English and created a clear overview for you here.
Before we jump into the map, I’d like to direct you to an article and a blog shared with me by two Americans living in Sendai, near the epicenter of the Tohoku Earthquake and where the tsunami struck. For those still feeling panicked by media reports, please read what Greg Harbin and Aimee McFarlane have to say. If you are willing to believe first-hand accounts, this will completely change your perspective on the situation.
Greg has been blogging through the quake and aftermath here.
And Aimee penned this excellent account for Salon titled “Why I’m Staying in Japan.”
Now, on to the map, I was able to get new readings for Monday, March 21, 2011 in Japanese from Yomiuri Shimbun. I have updated the infographic below with these new readings.
You can click the map above to open a larger view.
Source of Data: Yomiuri Shimbun. You can see the original Japanese map here.
You can still access my map with the March 18 readings if you would like to compare. Note that some labels differ because Yomiuri Shimbun is using some city names instead of prefecture names on the March 21 map or took readings at different nearby locations.
The readings for March 21 show small increases in some areas and small decreases in others. Overall the levels are slightly higher but are still far below levels that could affect human health. Levels near Fukushima have dropped considerably, down from 10.90 microsieverts on Friday, March 18, to 7.47 microsieverts on Monday, March 21. This is at the perimeter of the 60km evacuation area. Outside of this area the highest reading found was 0.340 microsieverts at Mito. Apart from this there are a few readings around the 0.1 microsievert level. Tokyo came in at 0.125 microsieverts on March 21. Most others are closer to the 0.05 microsievert level. None of these are of concern to human health.
The measurements on this map ware taken by the Yomiuri Shimbun, one of Japanese largest newspapers. I have seen separate readings from Asahi TV’s Hodo. Their readings were slightly different than these, but essentially the same. The point being that various private organizations are taking their own readings, so do not fall for those who claim the Japanese government or TEPCO is hiding or understating risks.
I should also point out that all of the measurements on this map are in microsieverts (μSv). A sieviert is a measure of the biological effect of radiation. 1,000 microsieverts = 1 millisievert. We all receive around 2 millisieverts (mSv) per year just from the natural background radiation.
To this end I have also put together some tables showing annual natural radiation exposures, annual exposures from common activities, and single dose exposures from medical procedures. In these tables I show the difference between these levels and current Tokyo levels, and the amount of time Tokyoites would need to be exposed to current radiation levels in order to equal the exposure from these natural sources and activities.
I have updated these tables to reflect the radiation level recorded for Tokyo on March 21.
All of the measurements in these tables are given in millisieverts (mSv).
Source: Table data from various studies and journals as cited here. Column for time it would take Tokyo levels to equal the annual or single dosage is based on the level of 0.125μSv/hour for Tokyo as found in the Yomiuri measurements. That’s 0.125 x 24 hours x 365 days which totals 1,095 microsieverts for the year or 1.095 millisieverts.
My purpose is not to deny the seriousness of the Fukushima situation or the fact that radiation levels have increased greatly from normal peacetime levels. Rather my purpose is to inject some reality into the overhyped media reports that have people as far away as Pennsylvania buying iodide tablets. Just because an increase is mathematically large doesn’t mean it is harmful.
I live 320km (200 miles) from Fukushima. Pennsylvania is 11,000km away (6,800 miles). If I am exposed to current radiation levels continuously for the next five years I will receive over that period the equivalent of what we all receive from nature’s background radiation each year. Arm yourself with math and scientific facts and then listen to the media reports. You’ll be able to put what is being said into real context.
A reliable statement on the actual risk came from the IAEA in their briefing on Friday (March 18):
Dose rates in Tokyo and other cities remain far from levels which would require action—in other words they are not dangerous to human health.
I will just update this post when new readings are available rather than creating new posts for the radiation map each time. That will help avoid the confusion that could be caused by multiple maps.
I hope you find this helpful.
Chris