[en] In April 1972, the National Environmental Research Center-Las Vegas initiated a ten-station network of continuous air samplers to monitor noble gas radioactivity on and around the nuclear explosive testing ground (Nevada Test Site). The network uses compressed air samplers designed and built by the Center. The samplers are described and operating experience and sample results are reported. After one year of operation, the network has shown its ability to document ambient levels of krypton-85 and to detect the occasional low-level releases of xenon-133 at the Nevada Test Site. Analysis of the data shows a small, but significant, higher level of krypton-85 concentrations measured at on-site locations compared to off-site. Average concentrations over the year were 15.7 +- 2.4 pCi/m³ off-site and 16.2 +- 2.4 pCi/m³ on-site. A systematic variation in krypton-85 levels at off-site stations was similar to that found in weekly grab samples collected off-site in Las Vegas during the preceding year