Crowdsourcing Radiation Monitoring

Safecast uses the power of the crowd to put radiation measurements in the cloud

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Last year, we had a story about how a team of election monitors were using the Internet to collect reports of voting problems and irregularities in the Sudan. That idea—collecting disparate reports from affected people and creating public databases out of them—has a lot of power.

Suppose, for example, you live in an area that recently had a big earthquake, tsunami, and nuclear reactor meltdown. The government issues radiation reports, but, you might say to yourself, that’s all fine and well, but how much radiation monitoring can they do? It’s not like the government can be everywhere at once—but we the people can. In fact, we are!

You’d face some challenges, of course. You have to get monitoring equipment out to lots of people. You have to try to ensure the accuracy of the data. You have to collect the data. You have to distribute the data in useful and meaningful ways. Come to think of it, there are a lot of challenges, and they’re not small ones. Nevertheless, the challenges are being met—by a group called Safecast. Here’s how they describe themselves: Safecast is a global sensor network for collecting and sharing radiation measurements to empower people with data about their environments.

My guest today is Joe Moross. He’s one of the lead safecasters in Japan and has been personally responsible for more than his share of Safecast measurements. Joe, welcome to the podcast, and given that it’s about midnight there, thanks for staying up.

Joe Moross: Thank you Steven. I’m happy to help.

Steven Cherry: Joe, lets start with the measurements themselves. Tell us what it’s like to go out and measure radiation.

Joe Moross: We have a number of different kinds of monitors, but the one we use the most is what we call a bGeigi. That’s kind of shortened for Bento Geigi because it’s kind of built in a box that looks like a Japanese lunch box. We hang that on our car and it has a GPS receiver and a data card and a little controller that helps us organize the data. And then we just hang it on the car and drive around, and every five seconds it records the time stamp, the GPS coordinates, and the current radiation level.

Steven Cherry: And the motion of the car doesn’t create a problem for collecting the data?

Joe Moross: Well, we’ve thought about that a bit and we decided that both based on theory and on our tests that it doesn’t seem to have any effect. We do have some averaging or smearing of the data because we take both an instantaneous reading and an average over the last 60 seconds, and we look at how much that changes and it doesn’t seem to be affected by speed or location too much, so we’ve decided that isn’t an issue and are happy with the readings we’re getting.

Steven Cherry: And so on the other hand I saw on the Safecast website that the radiation levels themselves can vary wildly even from one side of the street to the other.

Joe Moross: Yeah, we see micro hot spots, we see—depending on the specific reason that the radiation is there—you can get a very different reading even just centimeters different, if there’s a space where the cesium that came down and has adhered to something, or if there’s an area that has been cleaned up or the land has been turned over from tilling or something, then, yeah, but we’re trying to collect data on a scale much more—on a much finer scale than the government is doing. Instead of doing it like one sensor per city, basically at about every 5 seconds we’re about 50 meters to a hundred meters resolution.

Steven Cherry: So how many measurements have you personally taken?

Joe Moross: I think I’m responsible for about 400 000 of our data measurements, but quite a few number of those were—in the early days, we were trying to verify the equipment, so I took one of the sensors and hung it on the front window of my house and left it there for a week to determine both that the equipment was stable and—we didn’t have a fixed monitor network then—so this also acted as a fixed sensor, basically measuring the same place for about 200 000 measurements.

Steven Cherry: Yeah, tell us about the fixed sensors.

Joe Moross: The fixed sensor network—we have a number of different sensors—one doesn’t have the GPS module but otherwise it’s very similar. It uses the same Geiger counter, it has the same Arduino microcontrol, but it has a direct Internet connection. So what it does is, it measures the radiation once a minute and automatically uploads it to the Internet where it can be displayed by a number of different mappers, the most prominent one is Yahoo. Yahoo Japan actually created a page that’s linked off their weather reports that displays the readings from our fixed sensor network.

Steven Cherry: So how many measurements are in the database in total now?

Joe Moross: So for the mobile database—the last I heard was about a week ago—was just over one and a quarter million.

Steven Cherry: Wow, so you’ve taken quite a significant fraction of those.

Joe Moross: And it’s growing fast, because when we first had only a few mobile sensors and not a lot of time, we would put it on a car and drive maybe about once a week. But then we got volunteers who contacted us from up in the Fukushima region and they didn’t have to go anywhere to make the readings. They could basically start at their home and drive around in Iwaki and Fukushima City and Nihonmatsu and the places that are the areas of most concern. And as the number of sensors and number of volunteers has grown then the rates of the data coming in has been accelerating. So in July we were at the half million point and then we hit the million mark about a month ago and now we’re really close to 1.5 million and still accelerating.

Steven Cherry: Terrific. So the database has some geographical breadth to it. I guess also, there’s starting to be some historical depth. Is the data over time telling you anything yet?

Joe Moross: We’ve only just started to look at time series to see if we’re seeing decay rates and results of remediation and things like that. There is some trend in that but it is far from clear. It looks like there’s been a slight reduction in the areas we’ve covered repeatedly but it’s not obvious yet, and then the half-life of the most prominent isotope is 30 years, so we don’t expect to see any strong trend at this point.

Steven Cherry: So you’re up to a million and a half measurements and growing quickly. At a certain point, the real challenge is visualizing the data in useful ways. How’s that being done?

Joe Moross: We have a number of people who are making maps of the data. In fact, we just got a new visualization routine that we’re working on just this week. One of our other volunteers Lionel Bergeret, he’s added for the first time the ability for us to screen the data by date and location, so instead of seeing just a growing aggregation, you can, say, cut off everything from more than six months ago or just look at a window. In fact, it makes a really cool animation if you set it to just display one weeks data and let it run, you know, slide the date along from when it started to the present.

Steven Cherry: It looks like other people are using the data as well now.

Joe Moross: Well, one of the most important things about our data is that it’s all under a creative commons zero license, which makes it public domain. We are very emphatic about making the data available to any researcher or anyone that wants to use it. We really hope that somebody, maybe not even in contact with us, will take our data and do something very powerful with it, or make a new visualization, or that researchers will use it to correlate with, I don’t know, health data or weather data or anything else like that.

Steven Cherry: There’s a collaboration with Keio University?

Joe Moross: Yeah, since Safecast has gotten going, several of us have become designated as associate researchers at Keio University, and some of the people there are longtime experts in geographics and mapping and interpolation. We’re working with them to both manage the network and display the data.

Steven Cherry: There’s a great set of frequently asked questions on the website and I really liked one that asked, “Is Safecast an antinuclear activist group?” and the answer was, “Safecast was not antinuclear or pronuclear; we are prodata. Data is apolitical.” Here in the U.S., being prodata is actually taking a political side sometimes, though obviously it shouldn’t be.

Joe Moross: Well, I suppose our leader, Sean Bonner, he professes that we’re completely apolitical, but I would say if we do have a political agenda, it’s for transparency. We want data to be shared, information to be shared, and people to make their own decisions based on information that’s credible and independently verifiable.

Steven Cherry: Safecast got some money on Kickstarter. Is that the main source right now?

Joe Moross: It’s not our main source of funding, but it’s our largest initial source. The Kickstarter project generated, I think, $35 000 to $37 000, specifically to provide Geiger counters to people in the disaster-affected areas and I helped deliver a lot. Some of those, in the beginning, we took some to orphanages, to schools, and sometimes just to individuals that were in need of data. And that was—one of our first ideas was, you give these things to people that are in the areas that need to be measured and just have them go on the Internet. We had a page that they could put in their readings every day or as often as they could and that was our initial methodology for getting the information. But while we’re still doing that, and some people are still sending in data manually, the idea to automate it and make it much more mechanical has really expanded the amount of data we can collect.

Steven Cherry: And so that’s where the Arduino enhanced ones come in, is that right?

Joe Moross: Right. And we’ve had three or four generations of those. Right now, this week, we’re in the process of a functional test for our latest iteration of that that removes the SD card and the regular alkaline batteries to make something that has a rechargeable lithium battery and embedded memory, so you just plug it in as a USB device and then read out the data. But we’re going to take a little bit of time to prove that that has consistent measurements and is reliable and if it does then we’ll be rolling out that design as soon as possible.

Steven Cherry: How much does it cost to put something like that in someone’s hands?

Joe Moross: There’s a bit of debate about that because far and away the most expensive component in there is the Geiger counter, which is an Inspector Alert from International Medcom, and those retail for about $650 in the U.S. But we don’t pay that for them because we have a close cooperation with Medcom. We’ve got the Arduino board, which I think is a standard part as a—one of our volunteers had sold that as part of a kit device and it’s about $35 or $40. So the total parts may add up to about $850 or $1000, depending on which way you measure it, but the labor of course is all done by volunteers. The number we like to say is, it’s basically about a thousand dollars of stuff put together and deployed.

Steven Cherry: And so basically everyone is a volunteer at this point?

Joe Moross: Yes, everyone in the organization is completely volunteer.

Steven Cherry: That’s terrific. So how much do you think of your time do you devote to Safecasting?

Joe Moross: Well, I’d say I probably put in about 90 to 100 hours a week lately.

Steven Cherry: Wow.

Joe Moross: But I’m—there’s two of us, me and Peter Frank who’s the lead in Japan. We do nothing else other than Safecast right now, so we put in more time than most. But most of the other volunteers, they have full-time jobs so they help when they can, but even the key members who have other work, they’re still putting in probably 40 to 60 hours a week on Safecast.

Steven Cherry: Wow, that’s terrific. And I guess ultimately you all would like this to spread outside of Japan.

Joe Moross: We want it to be global and also we want it to, in the future hopefully, spread away from just radiation monitoring to pollution monitoring, both particulates and anything that’s going to affect health or has a broad effect on the environment and people.

Steven Cherry: That’s terrific. You know, it seems like it’s a little bit like genealogy or Wikipedia. There’s a real opportunity to build a global database that just continues forever and gets more useful.

Joe Moross: Well, there’s so many angles to this, and I concentrate on moving the sensors around and getting the sensors built specifically in Japan because that’s where I’ve lived for the last 22 years. But there are other people, in California and on the East Coast, that are working on how do you manage a database of this size?

Steven Cherry: That’s terrific. Well, thanks so much for talking to us and good luck with this great work.

Joe Moross: Thank you.

Steven Cherry: We’ve been speaking with Joe Moross about the organization Safecast, which is crowdsourcing the collection of radiation measurements in Japan. For IEEE Spectrum’s Techwise Conversations, I’m Steven Cherry.

Announcer: “Techwise Conversations” is sponsored by National Instruments.

This interview was recorded 16 November 2011.
Audio engineer: Francesco Ferorelli

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