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Records of recent climate from ice cores drilled in 2015 on the Guliya ice cap in the western Kunlun Mountains of the Tibetan Plateau, which with the Himalaya comprises the Third Pole (TP), demonstrate that this region has become warmer and moister since at least the middle of the 19th century. Decadal-scale linkages are suggested between ice core temperature and snowfall proxies, North Atlantic oceanic and atmospheric processes, Arctic temperatures, and Indian summer monsoon intensity. Correlations between annual-scale oxygen isotopic ratios (δ18O) and tropical western Pacific and Indian Ocean sea surface temperatures are also demonstrated. Comparisons of climate records during the last millennium from ice cores acquired throughout the TP illustrate centennial-scale differences between monsoon and westerlies dominated regions. Among these records, Guliya shows the highest rate of warming since the end of the Little Ice Age, but δ18O data over the last millennium from TP ice cores support findings that elevation-dependent warming is most pronounced in the Himalaya. This, along with the decreasing precipitation rates in the Himalaya region, is having detrimental effects on the cryosphere. Although satellite monitoring of glaciers on the TP indicates changes in surface area, only a few have been directly monitored for mass balance and ablation from the surface. This type of ground-based study is essential to obtain a better understanding of the rate of ice shrinkage on the TP.

In 2011 four ice cores were extracted from the summit of Alto dell'Ortles (3859 m), the highest glacier of South Tyrol in the Italian Alps. This drilling site is located only 37 km southwest from where the Tyrolean Iceman, ∼ 5.3 kyrs old, was discovered emerging from the ablating ice field of Tisenjoch (3210 m, near the Italian–Austrian border) in 1991. The excellent preservation of this mummy suggested that the Tyrolean Iceman was continuously embedded in prehistoric ice and that additional ancient ice was likely preserved elsewhere in South Tyrol. Dating of the ice cores from Alto dell'Ortles based on 210Pb, tritium, beta activity and 14C determinations, combined with an empirical model (COPRA), provides evidence for a chronologically ordered ice stratigraphy from the modern glacier surface down to the bottom ice layers with an age of ∼ 7 kyrs, which confirms the hypothesis. Our results indicate that the drilling site has continuously been glaciated on frozen bedrock since ∼ 7 kyrs BP. Absence of older ice on the highest glacier of South Tyrol is consistent with the removal of basal ice from bedrock during the Northern Hemisphere Climatic Optimum (6–9 kyrs BP), the warmest interval in the European Alps during the Holocene. Borehole inclinometric measurements of the current glacier flow combined with surface ground penetration radar (GPR) measurements indicate that, due to the sustained atmospheric warming since the 1980s, an acceleration of the glacier Alto dell'Ortles flow has just recently begun. Given the stratigraphic–chronological continuity of the Mt. Ortles cores over millennia, it can be argued that this behaviour has been unprecedented at this location since the Northern Hemisphere Climatic Optimum.

To ensure the health and safety of workers, integrated industrial hygiene methodologies often include biological monitoring of the workers to help understand their exposure to chemicals. To this end, a field-portable breath-analysis system was developed and tested to measure selected solvents in exhaled air. The exhaled breath data were evaluated using a physiologically based pharmacokinetic (PBPK) model to relate exposure to tissue dose. The system was designed to monitor workers every time they entered or left a work environment--a vast improvement over current 8-hour integrated monitoring strategies. The system combines (1) chemical dosimeters to measure airborne contaminant levels (analyzed in the field/ workplace); (2) real-time breath analysis to quantitate exposure; and 3) PBPK models to estimate internal target tissue dose. To evaluate the system, field tests were conducted at two locations: (1) at an incinerator in Tennessee monitoring benzene and toluene exposures; and (2) a waste repackaging facility in Washington State where hexane, trimethylbenzene, and methylene chloride was monitored. Exhaled breath was sampled and analyzed before and after each specific job task, which ranged from 15 min to 8 hours in duration. In both field studies several volunteers had posttask breath levels higher than pretask levels. The greatest increase corresponded to 573 ppb for methylene chloride and 60 ppb for toluene. Compared with breath analysis, the chemical dosimeters underpredicted the dosimetry, particularly for longer sampling intervals when the volume of air sampled may have diluted exposures. The results of the field studies illustrate the utility of monitoring workers for exposures throughout the day, particularly when job-specific tasks may indicate a potential for exposure.

This paper describes a field evaluation of a tandem mass spectrometer (TAGA) for use in measuring turbulence fluxes of trace gases. Measurements were made over a two-day period in a fallow farm field west of Columbus, OH. The results show that for weakly adsorbing species such as acetone, the effective time constant for the TAGA is

A comparison among modified and unmodified supercritical fluid extraction (SFE), enhanced-fluidity liquid extraction, and accelerated solvent extraction (ASE) techniques was made for the extraction of polynuclear aromatic hydrocarbons (PAHs) from an aged, spiked lignite coal fly ash. All of the attempted extraction conditions allowed the extraction of the PAHs to some degree, but no single extraction technique proved to be superior for all of the PAHs used. Three groups of PAHs with similar extraction efficiencies were identified. The group with the lowest molecular weights was best recovered using a 90% CO2-10% methanol mixture at 70 degrees C and 238 atm. The group of medium-molecular-weight PAHs was recovered equally well using any of three extraction conditions: SFE (100% CO2, 90 degrees C, and 238 atm), enhanced-fluidity liquid mixture (60% CO2-40% methanol, 70 degrees C, and 238 atm), and a methanol ASE mixture. The group of high-molecular-weight PAHs seemed to be equally well recovered with all of the attempted extraction conditions, but the enhanced-fluidity conditions (60% CO2-40% methanol, 70 degrees C, and 238 atm) had extraction recoveries (> 85%) with the lowest standard deviations (approximately 5%).

A comparison among supercritical fluid extraction (SFE), modified SFE, enhanced-fluidity extraction, and accelerated solvent extraction (ASE) techniques was made for the extraction of polynuclear aromatic hydrocarbons (PAHs) from an aged, spiked bituminous coal fly ash. Non-ASE extraction techniques used in this study could not recover PAHs with molecular weights greater than that of pyrene. ASE techniques using methylene chloride (with and without a static step) and toluene were able to recover most of the PAHs studied. None of the ASE techniques could quantitatively extract the low-molecular-weight PAHs from the bituminous fly ash. The medium-molecular-weight PAHs were best recovered with toluene ASE. The high-molecular-weight PAHs were best recovered with the toluene ASE technique (> 80%), but the overall precision of these measurements was low. Methylene chloride ASE with a static step recovered the high-molecular-weight PAHs with the next highest efficiency (approximately 55%) and had standard deviations less than 10% (longer extraction times [> 30 min] with the methylene chloride would increase the recoveries of these analytes.) A comparison of the results from this study with those of a previous study using lignite coal fly ash illustrates the difficulty in developing and adapting analyte-specific extraction methods for analytes that are adsorbed on different matrices.

An atmospheric sampling tandem mass spectrometer has been evaluated for aircraft monitoring of dimethyl sulfide (DMS) and then used for DMS monitoring during portions of six flights over the western North Atlantic Ocean. Laboratory evaluations demonstrated that the mass spectrometer is highly selective for DMS, and responds linearly over a wide range of mixing ratios. The detection limit for DMS is 1–2 ppt in dry air. However, the response is suppressed in the presence of water vapor, so the sample air must be dried or the response must be corrected for this effect. There appeared to be no consistent effect of altitude/pressure on instrument response. The mass spectrometer was installed on the Battelle Gulf stream G-1 research aircraft and used to monitor DMS and a number of other chemicals during flights over the western North Atlantic Ocean in August and September, 1992. DMS mixing ratios ranged from

Two direct air sampling interfaces have been evaluated in the laboratory for monitoring toxic air pollutants in real time by ion trap mass spectrometry in both single mass spectrometry and tandem mass spectrometry (MS/MS) modes. The mass spectrometer is the research-grade Finnigan MAT ion trap (ITMSTM) equipped with the Teledyne filtered noise field (FNF) module to eject unwanted ions and isolate only ions of interest. This results in enhanced sensitivity and selectivity for analyte ions of interest. MS/MS operation, for characterization of individual compounds with high sensitivity and specificity, is achieved by applying a supplementary RF signal to the end-caps of the ion trap. The direct air sampling interfaces are a semi-permeable helium-purged tubular membrane and an atmospheric sampling glow discharge ionization (ASGDI) source. Nonpolar and polar volatile organic compounds (VOCs) are measured at trace levels in air, using an environmental test chamber as the source of the target compound mixtures at known concentrations. Experiments conducted with the combination systems permit a comparison of the two direct air sampling interfaces for monitoring VOCs continuously in real time and illustrate the power of the FNF method to isolate ions with unit mass resolution and to perform MS/MS measurements.

A tandem mass spectrometer modified for aircraft applications was used to measure gas-phase formic and acetic acid mixing ratios over the western North Atlantic during late summer 1992. The sensitive, specific, and essentially real-time measurements provided by the mass spectrometer allow a true spatial evaluation of these compounds in the study area. Formic and acetic acid mixing ratios showed substantial vertical variation, varying by factors of up to 13 and 6, respectively, within 2-km profiles extending from the boundary layer into the free troposphere. Substantial horizontal variation was also observed at constant altitudes within both the boundary layer and free troposphere. Mixing ratios of the two acids were correlated (r²>0.70) throughout the study region.

This article describes a research aircraft for airborne measurements and the challenges that were overcome to deploy state-of-the-art measurement technology in an aircraft environment. We also focus on the chemical instrumentation and the recent addition of tandem mass spectrometry to the capabilities available for atmospheric characterization. The plane that we use to study atmospheric physical and chemical processes is a Grumman Gulfstream 1 (G-1), which is a twin-engine turboprop. The G-1 has a visual flight rule range exceeding 1500 nautical mi (endurance of about 6 h). It carries as much as 2800 lb of scientific payload with seats for four scientists and has a sampling speed range of 160-250 knots. The data acquisition system on the G-1 contains special interfaces to log data from a Long-Range Navigation system, the Global Positioning System, and an inertial navigation system, as well as particle measurement systems and other scientific probes. 3 refs., 7 figs., 2 tabs.

The fragmentation mechanism of tetraethyl ortho silicate and tetrapropyl ortho silicate was studied to determine if the consecutive alkene losses observed in their MS/MS daughter ion spectra were produced via a McLafferty rearrangement or by ion-neutral rearrangement mechanisms. The experiments were carried out using atmospheric pressure chemical ionization and low energy collision-induced dissociation. Deuterium labeling of the γ-position provided evidence that the rearrangement mechanism of the successive alkene losses proceeds predominantly via the ion-neutral complex mechanism. Because the energies imparted to the ions in this experiment are of the same order of magnitude as solution phase reactions, this mechanism may shed light on the formation of silica gels (e.g., aerogels) in that similar structures have been proposed as reaction intermediates in the polymerization of SiO2.

Measurement of nitrogen dioxide (NO2) and other oxidized nitrogen compounds in indoor environments can present some measurement difficulties not normally encountered in sampling outdoor air. This paper examines three methods that are in current use for monitoring indoor nitrogen dioxide. The methods include ozone-based and luminol-based chemiluminescence, and an electrochemical technique. We have examined these methods for accuracy, linear dynamic range, and interferences. Each of the methods was subject to interference. For indoor measurements, nitrous acid probably represents the most significant interference for the ozone-based chemiluminescence and electrochemical monitors.

Products of the photooxidation of toluene from an irradiated 5.1 ppm toluene/0.9 ppm NO/sub x/ mixture were identified by use of a triple-quadrupole MS/MS operated in an atmospheric pressure ionization mode. The reaction was carried out in a flow-mode 22.7-m/sup 3/ Telfon smog chamber. The steady-state reactant and product mixture was continuously transferred to the mass spectrometer inlet at 144 L/min. By using structurally similar standards, semiquantitative MS/MS analyses for many of the ring fragmentation products were conducted. Quantitative analyses by chromatographic methods and semiquantitative analyses by MS/MS were conducted for a variety of ring fragmentation products. The following products were found with yields of 1% (C/C) or greater: methylglyoxal, glyoxal, benzaldehyde, methylbutenedial, hydroxy-methylbutenedial, peroxyacetyl nitrate, oxoheptadienal, CH/sub 3/COOH, HCHO, hexadienal, and hydroxyoxo-heptadienal. The mutagenic activity of the steady-state product mixture was measured by using the Ames assay Salmonella typhimurium strain TA 100. The mutagenic activity data are discussed relative to our earlier findings that resulted from different reaction conditions.

For the first time, molecular ions from two different compounds have been simultaneously isolated in an ion-trap mass spectrometer and their subsequent tandem mass spectra (MS/MS) obtained. Isolation was achieved by applying a filtered-noise field (FNF) to the end-caps of a FinniganMAT ion-trap mass spectrometer (ITMS) using the Teledyne MEC/Hitachi HST-1000 Enhancement Kit. The HST-1000 generates a broadband waveform that would normally eject all ions from the trap. However, by setting notches in the waveform that correspond to certain resonant frequencies, individual masses can be isolated and stored in the trap without the need for the conventional DC voltage on the ring electrode. Using this FNF technique, the molecular ions of p-dichlorobenzene (m/z 146) and 1,3,5-trimethylbcnzene (m/z 120) were simultaneously isolated from a 42-component mixture of volatile organic compounds. Each molecular ion was collisionally dissociated by applying a resonance excitation (‘tickle’) voltage from the HST-1000, and the spectrum for each molecular ion was obtained by scanning the RF voltage to the ring electrode.

Recent research has demonstrated that nitrogen oxides are transformed to nitrogen acids in indoor environments, and that significant concentrations of nitrous acid are present in indoor air. The purpose of the study reported in this paper has been to investigate the sources, chemical transformations and lifetimes of nitrogen oxides and nitrogen acids under the conditions existing in buildings. An unoccupied single family residence was instrumented for monitoring of NO, NO2, NOy, HONO, HNO3, CO, temperature, relative humidity, and air exchange rate. For some experiments, NO2 and HONO were injected into the house to determine their removal rates and lifetimes. Other experiments investigated the emissions and transformations of nitrogen species from unvented natural gas appliances. We determined that HONO is formed by both direct emissions from combustion processes and reaction of NO2 with surfaces present indoors. Equilibrium considerations influence the relative contributions of these two sources to the indoor burden of HONO. We determined that the lifetimes of trace nitrogen species varied in the order NO approximately HONO > NO2 > HNO3. The lifetimes with respect to reactive processes are on the order of hours for NO and HONO, about an hour for NO2, and 30 minutes or less for HNO3. The rapid removal of NO2 and long lifetime of HONO suggest that HONO may represent a significant fraction of the oxidized nitrogen burden in indoor air.

Highly sensitive and specific continuous measurement of dimethylsulfide (DMS) in air has been demonstrated using triple quadrupole mass spectrometry with atmospheric pressure chemical ionization. Detection limits of 2 parts per trillion and 4 parts per trillion by volume in air are achieved for DMS using positive ion detection with benzene charge exchange and hot wire excitation, respectively. Either of these ionization modes provides sensitivity sufficient for continuous direct monitoring of dimethylsulfide in the atmosphere, with time response of approximately 1 s. This capability may be applicable to study the effect of oceanic DMS emissions on global climate. Detection limits in continuous monitoring were also determined for hydrogen sulfide (1 ppbv) and for methyl mercaptan, carbonyl sulfide, and carbon disulfide (≈ 10 ppbv).

We used real-time breath measurement technology to investigate the suitability of some volatile organic compounds (VOCs) as breath biomarkers for active and passive smoking and to measure actual exposures and resulting breath concentrations for persons exposed to tobacco smoke. Experiments were conducted with five smoker/nonsmoker pairs. The target VOCs included benzene, 1,3-butadiene, and the cigarette smoke biomarker 2,5-dimethylfuran. This study includes what we believe to be the first measurements of 1,3-butadiene in smokers' and nonsmokers' breath. The 1,3-butadiene and 2,5-dimethylfuran peak levels in the smokers' breath were similar (360 and 376 microg/m(3), respectively); the average benzene peak level was 522 microg/m(3). We found higher peak values of the target chemicals and shorter residence times in the body than previously reported, probably because of the improved time resolution made possible by the continuous breath measurement method. The real-time breath analyzer also showed the presence of the chemicals after exposure in the breath of the nonsmokers, but at greatly reduced levels. Single breath samples collected in evacuated canisters and analyzed independently with gas chromatography/mass spectrometry confirmed the presence of the target compounds in the postexposure breath of the nonsmokers but indicated that there was some contamination of the breath analyzer measurements. This was likely caused by desorption of organics from condensed tar in the analyzer tubing and on the quartz fiber filter used to remove particles. We used the decay data from the smokers to estimate residence times for the target chemicals. A two-compartment exponential model generally gave a better fit to the experimental decay data from the smokers than a single-compartment model. Residence times for benzene, 1,3-butadiene, and 2,5-dimethylfuran ranged from 0.5 (1,3-butadiene) to 0.9 min (benzene) for tau1 and were essentially constant (14 min) for tau2. These findings will be useful in models of environmental tobacco smoke exposure and risk.

We have developed and applied a new measurement methodology to investigate dermal absorption of chloroform while bathing. Ten subjects bathed in chlorinated water while breathing pure air through a face mask. Their exhaled breath was delivered to a glow discharge source/ion trap mass spectrometer for continuous real-time measurement of chloroform in the breath. This new method provides abundant data compared to previous discrete time-integrated breath sampling methods. The method is particularly well suited to studying dermal exposure because the full face mask eliminates exposure to contaminated air. Seven of the 10 subjects bathed in water at two or three different temperatures between 30 degrees C and 40 degrees C. Subjects at the highest temperatures exhaled about 30 times more chloroform than the same subjects at the lowest temperatures. This probably results from a decline in blood flow to the skin at the lower temperatures as the body seeks to conserve heat forcing the chloroform to diffuse over a much greater path length before encountering the blood. These results suggest that pharmacokinetic models need to employ temperature-dependent parameters. Two existing models predict quite different times of about 12 min and 29 min for chloroform flux through the stratum corneum to reach equilibrium. At 40 degrees C, the time for the flux to reach a near steady-state value is 6-9 min. Although uptake and decay processes involve several body compartments, the complicating effect of the stratum corneum lag time made it difficult to fit multiexponential curves to the data; however, a single-compartment model gave a satisfactory fit. Images Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6