RadNet national air monitoring program

Abstract

The United States Environmental Protection Agency has operated a variety of national radiological air monitoring systems for more than four decades. The current system, RadNet, operates approximately 140 fixed monitoring systems across the United States including Alaska and Hawaii. The system provides nearreal-time gamma spectroscopy data and limited gross beta radiation data as detected on a 4 in. air filter on a high volume air sampler. Filters are analyzed hourly and results are sent electronically to an EPA laboratory for review. Any anomalous results outside of normal background variation are reviewed by an EPA scientist. In addition to the fixed monitoring systems, there are 40 deployable units that include low and high volume air samplers and electronically transmit ambient gamma exposure readings. The system provided continuous data to the public and interested scientists during the Fukushima release. RadNet is able to remotely detect typical gamma emitting isotopes at levels several orders of magnitude below protective action guidelines. In order to provide even more sensitive analytical results, RadNet air filters are sent to an EPA laboratory for analyses approximately twice weekly. Potential updates to the system include improved radiation detectors and improved communication devices for deployable RadNet systems.