Japan Nuclear Information

Airborne Radiation Monitoring Status

No increased risk detected above background levels.

This page was prepared in response to public questions regarding potential air quality impacts from the damaged nuclear power plants in Japan, following the earthquake and tsunami that occurred on March 11, 2011.

The Air District continues working with US Environmental Protection Agency (EPA), California Air Resources Board, San Luis Obispo (SLO) County Office of Emergency Services and Public Health to assess the situation and keep the public informed. The U.S. EPA and the Federal Nuclear Regulatory Commission have indicated that there are no harmful levels of radiation expected to reach the United States. Monitoring still indicates very trace amounts of radiation from the Fukishima site at levels barely above the detection limit of the instruments, which is several thousand times less than the public health threshold. Real-time monitoring has shown us that all measurements in SLO County area are within normal background levels.

Information for SLO County is gathered from three monitoring networks: EPA (RadNet), California Department of Public Health and Pacific Gas & Electric (Diablo Canyon Power Plant). Both RadNet and the network established for Diablo Canyon use monitoring instruments that are extremely sensitive and can identify very small changes in ambient air levels. RadNet is a national network of monitoring stations that regularly collect air, precipitation, drinking water and milk samples for analysis of radioactivity. Real-time monitoring and basic radiation facts are available on EPA’s website.

The California Department of Public Health (CDPH), Radiologic Health Branch (RHB) also has a statewide network of monitoring stations that collect samples for analysis of radioactivity. The CDPH also has a useful set of FAQs concerning radiation from the Japanese nuclear plants. The California Department of Public Health is urging the public not to take potassium iodide tablets and for more information on this aspect please see the statement from CDPH.