An official website of the United States government.

RadNet

RadNet Air Filter Analysis Results From San Diego, CA

Air filters are collected from each RadNet stationary monitor and sent to the National Analytical Radiation Environmental Laboratory (NAREL) for gross beta air concentration screening and possibly additional analyses. Learn more about RadNet.

Air filters undergo three separate analytical processes, as illustrated below. Results from the initial hourly measurements of gamma radiation emitted from particulates takes place in Step 1. Air filter analysis results (Steps 3 and 4) are reported below in the conventional unit of curies (Ci) per cubic meter of air.  Learn more about curies and the international SI unit of becquerel (Bq).

Flowchart of RadNet air filter analysis process

On this page:

View RadNet Near-Real-Time Air Monitoring Results from San Diego, CA

Gross Beta Air Concentration Filter Analysis Results

Monitor operators change RadNet air monitor filters and send them to NAREL for analysis. A gross beta air concentration screening is performed at the laboratory on each filter, followed by gamma spectrometry if the beta activity is greater than the screening level of 1 pCi/m3. Following a known release, this screening level may be reduced and additional analyses may be performed. The graph below shows all beta air concentration filter results for this monitoring location.

Top of Page

Radionuclide-specific Air Filter Analysis Results

Gamma spectrometry results are viewable in the Radionuclide-specific Filter Analysis Results table below.

Columns are sortable. See results key below.

Top of Page

Annual Composite Sample Analysis Results

All air filters collected from a location for each calendar year are composited into one sample representing that location. The composite sample for each location is then analyzed by gamma spectrometry (see table above) and, on a four-year rotational basis, for plutonium (Pu-238 and Pu-239/Pu-240) and uranium (U-234, U-235 and U-238) (see table below).

Columns are sortable. See event key below.

Top of Page

Results Key

Result Description

Non-Detect

The radionuclide was not detected with 97.5% confidence. Either no result was measured or a result was less than twice the uncertainty level.

Not Analyzed

The sample was not tested for this radionuclide.

Top of Page

Event Key

Label Description

Non-Event

These air filters are not associated with any large scale radiological incident. Examples include analyses initiated in response to exceeding screening levels or analyses conducted in response to very low level detections by other international air monitoring agencies. Learn more about RadNet Air Filter Inquiries.

Composite

At the end of each year, scientists combine all the air filters for each monitor and run gamma analyses. Alpha analyses are performed on the composites from one-fourth of the stations on a four-year rotating schedule.

Event A

Chinese Nuclear Test
October 16, 1980

Air filter analysis results from July through December 1980 can be viewed in Environmental Radiation Data Report (ERD) 23 and 24. Search EPA Archive

Event B

Chernobyl, Ukraine
April 26, 1986

These air filters were analyzed in the 90 days following the Chernobyl Nuclear Power Plant incident. The results are not necessarily related to this event. Learn about EPA's Radiological Monitoring during Chernobyl.

Event C

Tokaimura, Japan
September 30, 1999

These air filters were analyzed in the 90 days following the Tokaimura Nuclear Reactor accident. The results are not necessarily related to this event. 

Event D

Los Alamos, New Mexico
May 8, 2000

These air filters were analyzed in the 90 days following the Cerro Grande fire, which threatened a historically contaminated site. The results are not necessarily related to this event.

Event E

Hanford, Washington
June 27, 2000

These air filters were analyzed in the 90 days following the fires at the Hanford Nuclear Reservation. The results are not necessarily related to this event.

Event F

Fukushima, Japan
March 11, 2011

These air filters were analyzed in the 90 days following the tsunami that damaged the Fukushima Daiichi Nuclear Power Plant. The results are not necessarily related to this event. Learn about EPA's Radiological Monitoring during Fukushima.

Event G

Los Alamos, New Mexico
June 26, 2011

These air filters were analyzed in the 90 days following the Las Conchas fire, which threatened a historically contaminated site. The results are not necessarily related to this event.

Note: All results (activity concentrations) have been radioactive decay corrected back to the sample collection end date/time (UTC).

Top of Page