RadNet stationary air monitors pull in air at an approximate flow rate of 60 cubic meters per hour. (Adults typically breathe at a rate of about 20 cubic meters per day.) The monitors collect any particles in the sample on a filter. Radiation detectors continuously measure the beta and gamma radioactivity from particles on the filter. Every hour, the stationary monitor sends an electronic report to EPA's National Analytical Radiation Environmental Laboratory (NAREL).
Most naturally occurring and man-made radionuclides emit either beta particles or gamma rays, and many emit both. The RadNet monitor sends a report to EPA that contains the total number of beta particles and gamma rays recorded by the detectors during the previous hour, called the count rate. The RadNet system alerts EPA staff if levels are significantly higher than normal for any monitor. EPA scientists then investigate the nature of the increased radiation level.
RadNet Stationary Monitor