Calendar Year

2008

• A new gamma clump was introduced for the Upper Los Alamos Canyon sampling stations.
• Stations 33 and 38 were opened in the summer to monitor sampling along the north side of Upper Los Alamos Canyon, south of Trinity Drive between 15th and 35th Streets. Background data are to be collected before sampling begins. Stations will be closed when sampling is complete.

2007

• In July stations 71, 72, 73, 74, 75 and 79 were installed along DP Road to improve sector coverage downwind of MDA-B during future clean-up operations.
• In March a temporary station 64 was installed to monitor Hillside 138 which is about 100 meters east of station 66 on Hillside 137. Once sufficient data had been collected, the station was closed at the end of the year.
• Station 18 was closed in March in response to complaints from residents. The ash pile cleanup was completed about this time.
• Station 52 was closed in January. The tank removal at TA-50 has been completed.

2006

• Station closings and openings (18, 40, 53 & 52)
• Station 18 was re-opened in November at a nearby location to continue downwind monitoring of the ash pile clean-up just north of the Los Alamos Airport terminal building.
• Station 18 was closed in August in response to complaints from residents.
• In August station 53 was re-opened to monitor MDA-C. It is on Pajarito Road at TA-50.
• Station 52 was installed in July to monitor the removal of a tank at TA-50. It will be removed when the operation is complete.
• Station 40 was opened in January at the east end of the Los Alamos Airport runway to provide sector coverage for residences near the eastern tip of Barranca Mesa.
• MDA-B stations
• A new gamma clump was introduced, exclusively for decommissioning and demolition (D&D) work at MDA-B.
• In June stations 42, 43, 44 and 46 were installed downwind of MDA-B to provide more comprehensive sector coverage for nearby communities during planned clean-up activities. These stations were installed to collect background data before any clean-up was planned to begin. Three of these stations are along East Road (SR 502); station 42 is on DP Road.

2005

• New station opened
• Station 18 was opened in October at the east end of North Mesa to provide downwind monitoring of the ash pile clean-up just north of the Los Alamos Airport terminal building.
• Closed sampler number 77 located at TA-36 (IJ site)
• This sampler was located in an old firing site that is a radiological control area with depleted uranium surface contamination. Depleted uranium has normally been detected in samples from this site because the sampler is located on top of the source. Even though this location may represent the highest possible concentrations onsite, it does not provide an indication of the amount of material being resuspended or transported offsite. The restart of the uranium, plutonium, and americium analyses for sites 23 and 30, provides a better estimate of the resuspension and offsite transport of depleted uranium.
• Discontinue all analyses for site 04, 05, and 31
• All analyses for site 04, 05, and 31 will be stopped at the beginning of 2005, but we will continue to collect samples. We will save these samples until the stack samples indicate that no accidental releases occurred during the sampling period because they may be needed to estimate exposures at TA-3 or the Los Alamos town site. Measurements of radioactive air contaminants at these sites have been consistently lower than at other nearby sites indicating that they are not needed to estimate maximum concentrations under typical operating conditions.
• Station status change
• Site 17 near the entrance to Bandelier and the replacement for site 25 (near the S-site cafeteria) are now considered compliance stations because public exposures would not otherwise measured at these locations. We are also installing radio communications at these sites, which are used at all compliance samplers, to help ensure that we meet the 95% sample collection criteria each year.
• Restart isotopic analyses for sites 23 and 30
• Beginning with the first quarterly samples for 2005, we will restart isotopic analyses for sites 23 and 30. These sites, along with site 49, measure much of the depleted uranium heading off site from the firing sites because they are in the predominant wind directions from the firing sites (N to E).
• Some changes may be made for the Area G network
• Some changes may be made to the Area G network. These may include moving site 35 NNE to the fence line and discontinuing uranium isotopic analyses for all area G samples. As of January 28, 2005 , these changes are not yet final.
• Changes to the gamma clumps
• Minor changes to the gamma clumps are needed to maintain comparability by having similar size sampled air volumes in each clump of filters. All filters from the AIRNET samplers are included in these gamma analyses. Beginning with the gamma analyses for 050103:
• eliminate clump CF (currently 17, 26, 39, and 77)
• move site 17 to clump CC (White Rock)
• move sites 26 and 39 to clump CH (Onsite)

2004

• Discontinue Sr-90 analyses
• We have never measured Sr-90 in the ambient air at concentrations greater than their 2s uncertainty since starting these analyses at the beginning of 2002. If the highest quarterly measurement were an annual average, it would represent a dose of about 0.04 mrem using the EPA NESHAP 10 mrem concentrations as dose conversion factors. Since this is objective evidence that Sr-90 cannot contribute to more than 10% of the offsite dose, these analyses will be discontinued.
• Reduce the counting time for the alpha isotopic analyses
• By cutting the counting time in half, two samples can be counted per day per instrument instead of one sample. The minimum detectable activity will increase by about 40%, but we still will be able to quantitatively measure concentrations less than 1% of the EPA NESHAP standard.
• Move site 25 to the back gate/Ponderosa campground
• This sampler would provide an indication of potential public exposures at the Ponderosa campground. Site 25 is too close to the WETF tritium stack to normally measure stack emissions. This move is planned, but the effective date is not yet known as of December 2003.
• Remove site 54 - TA-33 East
• This station was installed as part of the Consent Agreement. Tritium was measured from the D&D activities at TA-33, but these activities are now complete. There have been no measurable concentrations of plutonium, americium, or depleted uranium.
• Remove sites 76 and 78 at TA-15
• These two sites, along with site 77, were installed to measure releases from firing site activities. All three measure low levels of depleted uranium (DU), but site 77 consistently has the highest concentrations and will be continued. Measurable concentrations of plutonium and americium have not been measured.
• Discontinue isotopic analyses on the following samplers
• Archived filters can be analyzed if there is an accidental release or if high gross alpha, beta, or gamma measurements indicate the need for additional analyses. Over the past five years a few measurements have indicated the presence of plutonium, americium, or DU at these sites, but the maximum concentration for any sample was much less than 1% of the EPA public dose limit.

Site #	Station Name
04	Barranca School
05	Urban Park
23	TA-5 (formerly TA-52, Beta Site)
30	Pajarito Booster 2 (P-2)
31	TA-3

Beryllium

Beryllium

In the late 1980's and early1990's some AIRNET samples were analyzed for beryllium in an attempt to detect potential impact from regulated sources and releases from high explosive testing. All values were well below the New Mexico 30-day ambient air quality standard of 10 nanograms per cubic meter, and so these analyses were discontinued. Analysis of AIRNET samples for beryllium was restarted in 1998. Quarterly composited samples from 19 sites were analyzed for beryllium. These sites were selected because they were located near potential beryllium sources or in nearby communities. The number of AIRNET sites analyzed for beryllium was later expanded to include locations with different soil types and some dustier sites. In 2008 beryllium analysis was being done for around 40 stations.

The New Mexico ambient air quality standard for beryllium no longer exists, but there is a NESHAP standard of 10 nanograms per cubic meter (40 CFR Part 61 Subpart C National Emission Standard for Beryllium) that can be used, with EPA approval, as an alternative to meeting the emission standard for beryllium. Even though LANL does not need to use this alternative standard, since the permitted sources meet the emission standards, it can be used for comparison. The highest measured values are about one percent of this standard.

The following resource material is available. Web access may be restricted. Please contact envoutreach@lanl.gov for assistance in obtaining a copy.

• "Ambient Airborne Beryllium Measurements at Los Alamos National Laboratory (1989-2001)", J. Lochamy et al. LA-UR-03-0706

Gamma

Gamma-emitting Nuclides

Los Alamos has analyzed AIRNET filters for gamma-emitting nuclides for many years, with some Cs-137 data dating back to 1958. The Laboratory does not routinely emit significant quantities of gamma-emitting particulates into the atmosphere. Gamma spectroscopy is conducted primarily as a screening method to ensure that there have been no unreported, unplanned releases from non-monitored point or diffuse sources. These data are not required by DOE orders or the Clean Air Act.

Bi-weekly sampling period's samples from 5-9 stations are"clumped" together (non-destructively) to obtain lower detection limits and reduce analytical costs. If a high count is detected in any filter clump, it can subsequently be broken up and filters counted individually to determine which one(s) contain the radioactive material.

Tritium

Tritium

In 1999, the technique used to calculate tritium concentrations in ambient air was revised. Previously water vapor concentrations in the air were determined by gel uptake of moisture. In early 1998, it was discovered that the silica gel collection media was not capable of removing all of the moisture from the atmosphere leading to an underestimation of the atmospheric water vapor concentration. Data from the meteorological monitoring network provide much better measurements of atmospheric water vapor concentrations and have been used since. All individual data provided on these pages have been revised to reflect this enhancement.

NOTE: The tritium summary data for 1978-1996 found at this web site taken from the Laboratory's annual Environmental Surveillance Reports HAVE NOT been recalculated.

[See C. F. Eberhart, "Using Absolute Humidity and Radiochemical Analyses of Water Vapor Samples to Correct Underestimated Atmospheric Tritium Concentrations" LA-UR-98-1107. Proc.92nd Ann. Mtg Air & Waste Management Assoc. (June 1999).]

Filter Fractions

Filter Fractions

It was determined that the air concentration and sample fraction analyzed fields were incorrect between the years of 1981-1993 for Am-241, Pu-238, Pu-239, total U, U-234, U-235, and U-238.

Due to incomplete documentation of procedures, it was originally assumed that whole filters were analyzed. By meticulously examining handwritten notes, consulting with the appropriate personnel, and comparing calculated air concentrations to the annual concentrations reported in the Environmental Surveillance Reports, it was determined that half filters were analyzed instead.

The air concentrations had to be recalculated with the correct filter volumes. This means that the corrected air concentrations are twice that of the air concentrations previously posted for these years. The corrected data were posted to the web as of February 17, 2000.

Net Concentrations

Net Air Concentrations

In 2000, LANL began to subtract an average blank value from the analytical result to calculate a net air concentration. This is the current approved method for calculating air concentrations. Both net air concentrations and gross air concentrations, in which no blank correction has been applied, are posted to the web. In cases when the average blank value is negative, the net air concentration is greater than the gross air concentration. For tritium, americium, plutonium, and uranium isotopes, net air concentrations are calculated as far back as 1995. Alpha and beta net air concentrations are calculated as far back as 2000, and beryllium as far back as 1998.

Uncertainties

Uncertainties

The analytical and air concentration uncertainties for the alpha isotopics (Am-241, Pu-238, Pu-239, U-234, U-235, and U-238) for the period 1995 to 2000 were corrected after an error was discovered in the analytical laboratory documentation. All subsequent uncertainties are correctly reported.

Cerro Grande Fire Data

Cerro Grande Fire Data

From May 9, 2000 to May 14, 2004, air filters were collected more frequently than once every 2 weeks, due to the Cerro Grande Fire. These short-term filters were counted for gross alpha and beta and then halved. Half of each filter was dissolved and analyzed for americium, plutonium, and uranium isotopes. The other half was either dissolved for polonium-210 and lead-210 analysis or used in the quarterly composite (00Q2). For the AIRNET stations where the short term filters were analyzed for both the routine set of isotopics (U-234, U-235, U-238, Pu-238, Pu-239, Am-241) and polonium-210 and lead-210, no half filter remained for inclusion in the quarterly composite. In these cases, the short-term net air concentrations and uncertainties were combined, on a time-weighted basis, with the quarterly composite concentrations. Similarly, short-term alpha and beta net air concentrations were combined with the 000522 concentrations to better represent the two week period. Tritium data from 000522 were not affected since gel samples were left in the field for the entire two week period.