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Welcome to RCT Continuing Training. This training will discuss the process for: collecting and evaluating radiological air samples and submitting samples to HPAL. This training consists of viewing the online presentation and completing its associated exercise guide, Utrain number 53850. It is recommended that you have the exercise guide with you while following along with the online training
The Underground Nuclear Explosion Signatures Experiment (UNESE) sought to use 37 Ar as a tracer for measuring noble-gas migration in the soil surrounding historic Underground Nuclear Explosions (UNE). One unexpected observation was the presence of the much longer-lived isotope 39 Ar from historic UNEs. Quantifying the activity of 39 Ar proved difficult due to the lack of capability to measure significantly-above-background levels of 39 Ar and a general discomfort to repeatedly expose Ultra-Low-Background Proportional Counters (ULBPCs) to significant radioactivity. Because the whole-air samples collected for the 37 Ar tracer measurement were already being measured on the above-ground argon capability, it was decided to expand that capability to include 39 Ar. This document describes the efforts required to achieve quantitative reporting of the 39 Ar backgrounds measured during experiments at the sites of the historic Barnwell and Disko Elm UNEs.
A series of multi-physics experiments, referred to as Physics Experiment 1 (PE1) is underway at the United States’ Nevada National Security Site (NNSS). The PE1 series includes detonations of three underground chemical explosions in P-tunnel, with fully coupled (PE1 A), partially decoupled (PE1 D L ), and fully decoupled (PE1 B) emplacements. Canisters with gas tracers are imbedded in the explosives, and the tracers are released when the canister is destroyed by the detonation. A dedicated electromagnetic (EM) experiment (EMX) generates well-characterized EM signals at an underground location near the chemical explosive experiments. A series of atmospheric experiments (METEX, REACT, and METREX) release smoke and radioactive tracers around Aqueduct Mesa to test gas transport in complex topography. Each of the chemical explosive experiments includes a network of sensors to record seismic, acoustic, and electromagnetic waves, measurement of atmospheric conditions, and air sample collection for measurement of tracer concentration. EMX records EM signals underground and on the surface of Aqueduct Mesa. METEX, REACT, and METREX include measurement of atmospheric condition, as well as tracking smoke releases. REACT and METREX add low-level radioactive gas tracers to the atmospheric releases.
PNNL has successfully integrated a commercial aerosol detector and the imprinted micelle technology. The integrated systems have been shown to have a limit of detection between 33-47 particles with several options for data analysis presented that vary on computational requirements. It is possible to integrate these systems and receive response data on the second time scale. While more work is needed, these technologies are compatible, which opens up a large field of air sampling looking for specific contaminates.
This data set reports 13C (carbon) and 14C signatures of air from Spruce and Peatland Responses Under Changing Environments (SPRUCE) experimental study plots located in the S1-Bog at the Marcell Experimental Forest in northern Minnesota from 2016-2025 (2016-04-13 to 2025-09-24). Air measurements were collected approximately five times throughout each active growing season beginning in 2016 and included the 10 SPRUCE experimental plots (Plots 4, 6, 8, 10, 11, 13, 16, 17, 19, and 20) two ambient co-located ambient plots (Plots 7 and 21) and a site at the Marcell Experiment Station’s S2-Bog meteorological station (MET) located 1.7 km northeast of the SPRUCE experimental site on the S1-Bog. Air samples were assessed for both 13C- and 14C-CO2 (carbon-carbon dioxide) signatures. 13C and 14C isotopic signatures can be used in end-member analysis and C-cycle models to track the movement of C within the experimental ecosystem, calculate turnover times within plant tissues, and to test mechanisms used in models. This dataset contains one data file in comma separate (*.csv) format. Additional metadata are provided: one data dictionary and a file-level metadata file in comma separate (*.csv) format and a user guide in PDF (*.pdf) format.
This data set presents globally averaged atmospheric concentrations of chlorofluorocarbon 11, known also as CFC-11 or F-11 (chemical name: trichlorofluoromethane; formula: CCl3F). The monthly global average data are derived from flask air samples collected at eight sites in six locations over the period August 1980-July 1992. The sites are Barrow (Alaska), Cape Meares (Oregon), Cape Kumukahi and Mauna Loa (Hawaii), Cape Matatula (American Samoa), Cape Grim (Tasmania), Palmer Station, and the South Pole (Antarctica). At each collection site, monthly averages were obtained from three flask samples collected every week. In addition to the monthly global averages available for 1980-992, this data set also contains annual global average data for 1975-1985. These annual global averages were derived from January measurements at the South Pole and in the Pacific Northwest of the United States (specifically, Washington state and the Oregon coast).For access to the data files, click this link to the CDIAC data transition website: http://cdiac.ess-dive.lbl.gov/ndps/db1010.html
For more than a decade, the United States has performed environmental monitoring by collecting and analyzing air samples for a handful of biological threat agents (BTAs) in order to detect a possible biological attack. This effort has faced numerous technical challenges including timeliness, sampling efficiency, sensitivity, specificity, and robustness. The cost of city-wide environmental monitoring using conventional technology has also been a challenge. A large group of scientists with expertise in bioterrorism defense met to assess the objectives and current efficacy of environmental monitoring and to identify operational and technological changes that could enhance its efficacy and cost-effectiveness, thus enhancing its value. The highest priority operational change that was identified was to abandon the current concept of city-wide environmental monitoring because the operational costs were too high and its value was compromised by low detection sensitivity and other environmental factors. Instead, it was suggested that the focus should primarily be on indoor monitoring and secondarily on special-event monitoring because objectives are tractable and these operational settings are aligned with likelihood and risk assessments. The highest priority technological change identified was the development of a reagent-less, real-time sensor that can identify a potential airborne release and trigger secondary tests of greater sensitivity and specificity for occasional samples of interest. This technological change could be transformative with the potential to greatly reduce operational costs and thereby create the opportunity to expand the scope and effectiveness of environmental monitoring.
Recent advances in the development of large eddy simulation (LES) atmospheric models with corresponding atmospheric transport and dispersion (AT&D) modeling capabilities have made it possible to simulate short, time-averaged, single realizations of pollutant dispersion at the spatial and temporal resolution necessary for common atmospheric dispersion needs, such as designing air sampling networks, assessing pollutant sensor system performance, and characterizing the impact of airborne materials on human health. The high computational burden required to form an ensemble of single-realization dispersion solutions using an LES and coupled AT&D model has, until recently, limited its use to a few proof-of-concept studies. An example of an LES model that can meet the temporal and spatial resolution and computational requirements of these applications is the joint outdoor-indoor urban large eddy simulation (JOULES). A key enabling element within JOULES is the computationally efficient graphics processing unit (GPU)-based LES, which is on the order of 150 times faster than if the LES contaminant dispersion simulations were executed on a central processing unit (CPU) computing platform. JOULES is capable of resolving the turbulence components at a suitable scale for both open terrain and urban landscapes, e.g., owing to varying environmental conditions and a diverse building topology. In this paper, we describe the JOULES modeling system, prior efforts to validate the accuracy of its meteorological simulations, and current results from an evaluation that uses ensembles of dispersion solutions for unstable, neutral, and stable static stability conditions in an open terrain environment.
In October-November 2011 we measured the trace gas emission factors from 7 prescribed fires in South Carolina, U.S. using two Fourier transform infrared spectrometer (FTIR) systems and whole air sampling (WAS) into canisters followed by gas-chromatographic analyses. The fires were intended to emulate high-intensity burns as they were lit during the dry season and in most cases represented stands that had not been treated with prescribed burns in 10+ years, if at all. A total of 97 trace gas species are reported here from both airborne and ground-based platforms making this one of the most detailed field studies of fire emissions to date. The measurements included the first data for a suite of monoterpene compounds emitted via distillation of plant tissues during real fires. The known chemistry of the monoterpenes and their measured abundance of ~0.40% of CO (molar basis), ~3.9% of NMOC (molar basis), and ~21% of organic aerosol (mass basis), suggests that they impacted post-emission formation of ozone, aerosol, and small organic trace gases such as methanol and formaldehyde in the sampled plumes. The variability in the terpene emissions in South Carolina (SC) fire plumes was high and, in general, the speciation of the emitted gas-phase non-methane organic compounds was surprisingly different from that observed in a similar study in nominally similar pine forests in North Carolina ~20 months earlier. It is likely that the slightly different ecosystems, time of year and the precursor variability all contributed to the variability in plume chemistry observed in this study and in the literature. The ΔHCN/ΔCO emission ratio, however, is fairly consistent at 0.9 ± 0.06 % for airborne fire measurements in coniferous-dominated ecosystems further confirming the value of HCN as a good biomass burning indicator/tracer. The SC results also support an earlier finding that C 3 -C 4 alkynes may be of use as biomass burning indicators on the time-scale of hours to a day. It was possible to measure the chemical evolution of the plume on four of the fires and significant ozone (O 3 ) formation (ΔO 3 /ΔCO from 10-90%) occurred in all of these plumes. Slower O 3 production was observed on a cloudy day with low co-emissions of NO x and the fastest O 3 production was observed on a sunny day when the plume almost certainly incorporated significant additional NO x by passing over the Columbia, SC metropolitian area. Due to rapid plume dilution, it was only possible to acquire high quality downwind data for two other species (formaldehyde and methanol) on two of the fires. In all four cases significant increases were observed. Finally, this is likely the first direct observation of post-emission methanol production in biomass burning plumes and the precursors likely included terpenes.
Abstract. Hydrogen (H2) is a promising low-carbon alternative to fossil fuels for many applications. However, significant gaps in our understanding of the atmospheric H2 budget limit our ability to predict the impacts of greater H2 usage. Here we use NOAA H2 dry air mole fraction observations from air samples collected from ground-based and ship platforms during 2010–2019 to evaluate the representation of H2 in the NOAA GFDL-AM4.1 atmospheric chemistry-climate model. We find that the base model configuration captures the observed interhemispheric gradient well but underestimates the surface concentration of H2 by about 10 ppb. Additionally, the model fails to reproduce the 1–2 ppb yr−1 mean increase in surface H2 observed at background stations. We show that the cause is most likely an underestimation of current anthropogenic emissions, including potential leakages from H2-producing facilities. We also show that changes in soil moisture, soil temperature, and snow cover have most likely caused an increase in the magnitude of the soil sink, the most important removal mechanism for atmospheric H2, especially in the Northern Hemisphere. However, there remains uncertainty due to fundamental gaps in our understanding of H2 soil removal, such as the minimum moisture required for H2 soil uptake, for which we performed extensive sensitivity analyses. Finally, we show that the observed meridional gradient of the H2 mixing ratio and its seasonality can provide important constraints to test and refine parameterizations of the H2 soil sink.
New particle formation (NPF) is the atmospheric process whereby gas molecules react and nucleate to form detectable particles. NPF has a strong impact on Earth's radiative balance as it produces roughly half of global cloud condensation nuclei. However, the time resolution and sensitivity of current instrumentation are inadequate in measuring the size distribution of sub-3 nm particles, the particles critical for understanding NPF. Here we present the Condensation Particle Counters For Atmospheric Rapid Measurements (CPC FARM), a method to measure the concentrations of freshly nucleated particles. The CPC FARM consists of five CPCs operating in parallel, each configured to operate at different detectable particle sizes between 1–3 nm. This study explores two methods to calculate the size distribution from the differential measurements across the CPC channels. The performance of both inversion methods was tested against the size distribution measured by a pair of stepping particle mobility sizers (SMPSs) during an ambient air sampling study in Pittsburgh, PA. Observational results indicate that the CPC FARM is more accurate with higher time resolution and sensitivity in the sub-3 nm range compared to the SMPS.
The cloud condensation nuclei counter measures the concentration of aerosol particles by drawing an air sample through a column with thermodynamically unstable supersaturated water vapor that can condense onto aerosol particles. Particles that are activated, i.e., grown larger in the process, are counted and sized by an optical particle counter (OPC). In this way the CCN measures activated ambient aerosol particle number concentration as a function of supersaturation. ARM operates both one- and two-column versions of the CCN.
The continuous light absorption photometer (CLAP) operates on the same principle as the particle soot absorption photometer (PSAP), i.e., continuously measuring transmission through a filter substrate as sample air is drawn through it. The absorbing aerosol particles are collected in the filter. The CLAP is part of the aerosol observing system (AOS).
This data set contains ice-nucleating particle (INP) concentration spectra collected during the SAIL-Net sampling period, which complemented the Surface Atmosphere Integrated Field Laboratory (SAIL) campaign in the East River watershed near Crested Butte, Colorado. SAIL-Net was a distributed aerosol measurement network designed to investigate aerosol variability across complex mountainous terrain. The data set includes samples from multiple SAIL-Net sites, including AOS, Gothic, Snodgrass, Pumphouse, Irwin, and Top. INP concentrations are reported as a function of freezing temperature, together with confidence limits, sampling times, site location, elevation, sampled air volume, and treatment information. These data provide an analysis-ready record of the INPs across the SAIL-Net network.
Molecular hydrogen, methane, water vapor and tritium concentrations near stratopause from air samples collected on Aerobee flight with liquid hydrogen cooled cryocondenser
Mass and infrared spectrometric and gas chromatographic analysis of air samples from space station simulator during 90 day manned test
Potassium permanganate (KMnO4) was evaluated for application in removing mercury vapor from exhaust air systems. The KMnO4 may be used in water solution with a liquid spray scrubber system or as a solid adsorber bed material when impregnated onto a zeolite. Air samples contaminated with as much as 112 mg/cu m of mercury were scrubbed to 0.06mg/cum with the KMnO4-impregnated zeolite (molecular sieve material). The water spray solution of permanganate was also found to be as effective as the impregnated zeolite. The KMnO4-impregnated zeolite was applied as a solid adsorber material to (1) a hardware decontamination system, (2) a model incinerator, and (3) a high vacuum chamber for ion engine testing with mercury as the propellant. A liquid scrubber system was also applied in an incinerator system. Based on the results of these experiments, it is concluded that the use of KMnO4 can be an effective method for controlling noxious mercury vapor.