RadNet Air Filter Analysis Results From Seattle, WA

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 in the following graphic. 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 later on this page 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:

Gross beta air concentration filter analysis results
Radionuclide-specific air filter analysis results
Annual composite sample analysis results
Results key
Event key

View gamma radiation monitoring results in near-real-time on the RadNet Dashboard.

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 following graph shows all beta air concentration filter results for this monitoring location.

Radionuclide-specific Air Filter Analysis Results

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

Columns are sortable. See results key.

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 the following table).

Columns are sortable. See event key.

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.

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).