You might be curious to know why a reported weather data measurement doesn’t seem accurate. One reason is that weather data depends on where the measurement station is located. What this means is that in order to get precisely accurate weather data you either have to be as close as possible to where the weather stations are located, or you need to get your personal weather station. Measuring environmental radiation works similarly. Location of where the radiation detector is installed is an important factor in obtaining reliable radiation values at specific places. The U.S. Environmental Protection Agency (EPA) and other government agencies have a network of detectors for environmental radiation; however this infrastructure is not adequate and not relevant enough to address the lack of location-specific radiation data. In addition, some of the data generated from these detectors are not openly available to the public.
One approach to complement these networks is to involve citizens to participate in community environmental radiation monitoring. This concept, known as Citizen Radiation Monitoring (CRM), is a citizen science application which provides people with environmental radiation data that is accessible and pertinent to their location. This data can also serve as a validating tool to information supplied by government agencies.
This month, as part of NRDC’s CRM project, I got the opportunity to install a radiation monitoring system at a volunteer’s house in Shrub Oak, NY. Our volunteer was interested in monitoring the radiation levels in his backyard as he lives nine miles from the Indian Point Energy Center’s two operating nuclear reactors.
This radiation monitoring system installation is a collaboration between NRDC, Safecast, and International Medcom, IMI. Installation of the radiation monitoring station took less than an hour. The radiation monitoring system consists of a radiation detector and a near real-time data communication module (called “Pointcast”). The detector unit is intended to be installed outside of the house while the data communication module can be installed inside or outside. The detector system used is the dual sensor Hawk Radius. The pancake detector in the Hawk Radius detects alpha, beta, and gamma radiation. The Hawk’s compensated gamma sensor detects gamma radiation only. Thus each installation provides two data streams, one for each sensor.
The Pointcast measures data and transmits it every 5 minutes to a dedicated data transmission and visualization system. The system stores the data and is publicly accessible for further processing and visualization. An integrated SD card records the configuration as well as measurement data in case there is a communication problem.
Data from the Pointcast system can be seen at http://realtime.safecast.org. Each of the two radiation sensors in the Hawk Radius has its own dedicated webpage. For example, for the installation discussed above, the radiation data can be seen at http://realtime.safecast.org/sensors/200041/ for the Pancake sensor and http://realtime.safecast.org/sensors/200042/ for the compensated gamma sensor. The pages show the sensor location and ID number, as well as a status indication, at the top, and a map showing the sensor location to the right. The most recent reading is given in bold black letters, both in CPM and μSv/h, with the previous high reading in bold red. A small time series graph of the previous month appears to the right of the numerical readings. Clicking on “More sensor data” below the small graph will open a page for that sensor through which all collected data can be accessed. Clicking on the graph itself will open a detailed graph window. Actual counts are indicated by small orange crosses, while the simple moving average trend line is shown in blue.
This well- developed radiation monitoring system demonstrates that citizen-based monitoring systems can provide open radiation data to the public which is relevant to the area where they live. Involving more volunteers in the future could expand citizen radiation monitoring around Indian Point, the other 97 operating U.S. reactors and other man-made sources of radiation in the environment.