FAQ

JAPAN

Is it safe for me to visit Japan?

Short answer: Most likely.
Long answer: Depending on where in Japan you are planning to visit, radiation levels are no higher and sometimes lower than any other major city around the world. From our own measurements we can tell you that Tokyo and Los Angeles have similar radiation readings and the levels in Hong Kong are even higher than Tokyo. One explanation for this is that Japan may have had a lower average background radiation level than many other places before March 11, 2011 so even if overall levels increased, they may still be within the scope of what is average. It’s also worth noting that air travel, especially transcontinental flights subject passengers to elevated radiation, sometimes 20x as much as one might experience on the ground so it’s very likely that a person will be exposed to more radiation on the flight to Japan than the entire time they are on the ground there.
One caveat: Food measurements are still largely misunderstood and we can not yet make any claims to contamination levels of food within, our outside of Japan.

Did the contamination from Fukushima Daiichi spread outside of Japan?

Short answer: Yes.
Long answer: Traces of particles released by the event at Fukushima Daiichi have been found in every corner of the earth where they have been looked for. The world is one giant ecosystem and when a major contamination event takes place evidence of it can be found everywhere. It’s worth noting that there are also global traces of previous nuclear events such as Chernobyl, Hiroshima and Nagasaki, widespread nuclear testing from the 1950′s – so much so that there is actually a market for iron and concrete produced prior to WWII for the purpose of shielding environments for isotope identification, as all materials produced after WWII are contaminated and have a higher background radiation level.
One caveat: According to the research we’ve found, it seems 80% of the contamination went into ocean, 18% into Japan, and 2% globally.

Are the radiation levels changing?

Short answer: No
Long answer: While occasionally news of a “new hotspot” is being reported in the media, the reality is that these hotspots have existed (at least) since the 3/11 event but just haven’t been measured. Since 3/11 people have become much more aware of radiation and their immediate surroundings and are doing more measurements on their own, because of this much more granular data is being gathered and so hotspots which previously may have gone unnoticed are being discovered more regularly. The major contamination from Fukushima Daiichi is Cs137 which has a 30 year half-life, so it will be quite a while until effected areas see a radiation level decrease. Cs134 is also prevalent and has a 2 year half-life so this will be noticeable sometime in 2013
One caveat: Just because levels haven’t changed doesn’t mean they can’t. A new event involving a release of further radiation from any of the reactors at Fukushima Daiichi could result in new contamination. Additionally, a number of environmental factors may be involved in moving the existing contamination around to some extent.

Is Fukushima Daiichi stable?

Short answer: No
Long answer: All reports suggest that efforts to contain the contamination from the plant are ongoing, however access to the 20K exclusion zone around the plant is restricted and very difficult for anyone to research so independent confirmation of published reports is difficult to obtain.
One caveat: Information coming from the plant is fragmented and from various sources so it’s difficult to have a very clear idea of the exact situation inside the Fukushima Daiichi plant.

SAFECAST

What is the source of Safecast’s data?

Short answer: We collected it ourselves using industry standard 2″ pancake sensors.
Long answer: There are a number of different kinds of data represented on the Safecast website including crowd sourced measurements and aggregate data released by other agencies, however the official “Safecast data” that we reference and publish for others to use was collected by trained Safecast volunteers using professional quality devices. We use a combination of off the shelf commercial radiation monitors and devices we’ve built ourselves to better serve a specific purpose. In both of these cases the devices use the same sensor, the LND7317 which is commonly referred to as the 2″ pancake. This is a highly sensitive piece of equipment that is used by nuclear professionals all over the world so we’re confident and stand behind the readings taken with our devices. Additionally we use numbers of devices simultaneously to ensure against single device failure.
One caveat: The world is a big place and it’s not reasonable to think we’ll be able to measure every inch of it by ourselves, and as we continue to grow we’ll soliciting more crowd sourced measurements, but we’re also working very hard to make variations in equipment used transparent, and to ensure that all data we publish is interoperable.

What are differences in the data published by Safecast and official/governmental sources?

Short answer: Safecast data has much higher resolution geographically and better consistency.
Long answer: We know from our efforts that radiation levels can fluctuate in very short distances, sometimes simply crossing a street can yield dramatically different readings. Readings that have been published by official sources are not that specific and sometimes have been just a single reading for an entire city. We feel those readings are at best too vague to be useful and at worse intentionally misleading. Because of this our efforts have been to map readings on a street by street level, so that readings as specific as a street address can be looked at. Additionally it’s not clear what devices are used for the governmental reports, at Safecast we use the same device on the same surface under the same consistency. Finally all Safecast data is freely and openly published using a CC0 designation, all the data from governmental sources is use restricted somehow.
One caveat: How measurements are taken is as important as what the measurement is. Some agencies take readings at 10 meters above ground. Since we don’t know many people who spend their time floating 10 meters above ground, we take our readings closer to 1.5 meters above ground which is where people actually are.

Is Safecast an anti nuclear activist group?

Short answer: No
Long answer: Safecast is not anti nuclear, or pro nuclear – we are pro data. Data is apolitical. Safecast was created because we identified a lack of data and realized we could help fill that gap. Our goal is simply to provide more information, data where it didn’t exist so that people can make more informed decisions based on fact rather than the fear and speculation that comes from uninformed rumor.
One caveat: It’s worth noting that data can be interpreted in different ways, and visualized to highlight or downplay different aspects which is why in addition to our our visualizations we make our raw data available for anyone to examine and interpret on their own.

Is Safecast working with the Government?

Short answer: No
Long answer: In efforts to remain independent and uninfluenced by politics of any kind, Safecast is not working with any government or government agency directly. We have not reached out to any government, nor has any government contacted us.
One caveat: Because of how freely we publish our data, it’s impossible for us to know if any governments are using our data after we publish it or not.

Are readings effected by Driving?

Short answer: No
Long answer: Under normal conditions radiation the speed of a moving car (with a geiger counter attached) does not effect the readings taken when compared against readings taken in the same area with a still sensor. Safecast has verified this with our collaborations with Keio, Tokyo and Nihon Universities.
One caveat: Safecast’s “bGeigie” system is mounted outside of the car so that readings are not effected by the car itself. Some other groups have taken mobile readings from within a car which provides shielding and blocks out much of the radiation so it’s important to verify how all readings were taken.

RADIATION MONITORING

What kind of Geiger counter should I buy?

Short answer: Something by a “googleable” brand name, that measures alpha, beta and gamma radiation.
Long answer: Radiation measurement is not a simple as measuring something like temperature. It’s important that if you are going to purchase a sensor that it actually gives you useful information. A rule of thumb is that any device that gives only red/green or safe/unsafe feedback may not be detailed enough – it’s important to know the scope of the measurement. It’s also worth knowing why you want a geiger counter. If you want to measure radiation in the air and on surfaces near you, then a geiger counter is the device you want. If you want to measure food/water contamination or to see if you or your family have been irradiated, a geiger counter is not the right equipment and will not help you. We also recommend you stay away from any company that didn’t sell geiger counters before March 2011.
One caveat: After the 3/11 Fukushima Daiichi event the global demand for geiger counters sky rocketed. This has resulted in both a significant backorder time from major and reputable manufactures and an increase in availability of less accurate or poorly constructed devices. Because of this it’s very important to make sure any device you buy is reliable.

What is Safe?

Short answer: Good question.
Long answer: Unfortunately there is very little agreement within the health physics world about what is safe and what is unsafe. While there are some things that are generally agreed upon, children and pregnant women are at greater risk for example, there is no clear measurement that is the cut off point for safe or not. What’s most important is being aware of what you are exposed to, and what others are exposed to so you can decide if that is acceptable or not. The matter is very complex because risk factors are very different for individual people based on age, existing health issues, exposure time, areas of exposure, etc… therefore risk is best gauged on an individual basis and not generalized to the entire population.
One caveat: Individual comfort levels should not be discounted, and different people will be more or less comfortable with various levels.

Alpha, Beta, Gamma?

Short answer: Confusing isn’t it?
Long answer: These are the three kinds of radiation that are most commonly associated with nuclear plants. Gamma is very high energy and gamma particles can pass through walls, buildings, and people. A very high dose of gamma radiation can kill a person almost immediately. Alpha and Beta are lower energy, and can be blocked with a sheet of paper or thick clothing. Alpha and beta pose a greater risk if they are inhaled or ingested. The Cs137 that was released by Fukushima Daiichi is primarily a beta emitter which is why food contamination is such a concern.
One caveat: A lot of readings that are being published are gamma only, which Safecast doesn’t feel tells the full story.

How can I find out the radiation level near me?

Short answer: We’re working on that.
Long answer: The best bet from our perspective is to check out the maps we link to above. Hopefully some of those will give you some information. If not stay tuned or get in touch with us to see when we might be able to get data from your area.
One caveat: The wold is a big place and until recently no one seemed to be concerned with mapping this kind of info, so it’s a big job but we’re doing what we can.

Has Safecast found evidence of plutonium, iridium or strontium?

Short answer: No
Long answer: While we’re aware that other organizations have claimed to have detected these particles, though in very small traces, no samples that Safecast have looked at have contained them.
One caveat: Safecast is a group of volunteers doing what we can, but unfortunately do not have our own fully stocked isotope lab. Because of these we can’t analyze as much as we’d like and rely on the help of labs we work with to do deep investigation for us.