The RadNet system monitors the nation's air, precipitation and drinking water to track radiation in the environment. Over time, RadNet sample testing and monitoring results show the fluctuations in normal background levels of environmental radiation. The RadNet system will also detect higher than normal radiation levels during a radiological incident. There are several types of RadNet monitoring results available:
RadNet air monitoring and sampling stations are located across the entire U.S., with at least one fixed-air monitoring station located in each state, the District of Columbia and Puerto Rico. There are monitoring locations in most major population centers.
In addition to providing near-real-time exposure rate and/or gamma gross count rate measurements, the filters on RadNet air monitors capture particles from the air (airborne particulates). Staff analyze these filters and calculate the concentration of radionuclides on the filters to find trends in airborne radiation.
EPA scientists routinely test precipitation samples from sites in the U.S. to find trends in radionuclide concentration. There were precipitation samples collected from 28 sites in 2018. The stations submit precipitation samples to NAREL following rainfall, snow or sleet events. Under normal conditions, scientists composite the samples and analyze them monthly. The composite sample is analyzed for gamma-emitting nuclides.
EPA's RadNet program obtains quarterly drinking water samples from sites across the country for laboratory analysis. There were drinking water samples collected from 66 sites in 2018.