A portable Wavelength Scanned-Cavity Ring-Down Spectrometer (Picarro L2120) fitted with a diffusion sampler (DS-CRDS) was used for the first time to continuously measure δ¹⁸O and δ²H of stream water. The experiment took place during a storm event in a wet tropical agricultural catchment in north-eastern Australia. At a temporal…

Temperature reconstructions across Heinrich stadials 1–3 are presented from an absolute-dated speleothem from Abaco Island in the Bahamas to understand the nature of climate change across these intervals in the subtropical Atlantic. The stalagmite carbonate record, dated by the U–Th geochronometry technique, includes higher δ¹⁸O and …

Insights into the effects of stormwater control measures (SCMs) on urban stream hydrology and in-stream processes are required to understand their effectiveness in mitigating the environmental problems associated with urbanization. Stable water isotopes were applied to understand processes occurring within SCMs and their effects on water sourcing in urban streams. We sampled ten…

The isotopic composition of near surface (or planetary boundary layer) water vapor on the south coast of Iceland (63.83°N, 21.47°W) has been monitored in situ between November 2011 and April 2013. The calibrated data set documents seasonal variations in the relationship between δ¹⁸O and local humidity (ppmv) and between deuterium…

Laser-based spectroscopic techniques, such as cavity ring-down spectroscopy (CRDS), provide a new, costeffective and more widely available approach to measure the oxygen isotope ratio in water molecules, H218O/H216O (d18O), and are used increasingly to measure d18O in the world’s oceans. Here, we present results froman interlaboratory comparison designed to evaluate the quality of…

Deuterium (dD) and oxygen (d18O) isotopes are powerful tracers of the hydrological cycle and have been extensively used for paleoclimate reconstructions as they can provide information on past precipitation,temperature and atmospheric circulation. More recently, the use of 17O excess derived from precise measurement of d17O and d18O gives new and additional insights in tracing the…

A correction for the undesirable effects of direct and indirect cross-interference from water vapour on ammonia (NH₃) measurements was developed using an optical laser sensor based on cavity ring-down spectroscopy. This correction relied on new measurements of the collisional broadening due to water vapour of two NH₃ spectral…

Carbon dioxide and oxygen are tightly coupled in land-biospheres CO2 - O2 exchange processes, while they are not coupled in oceanic exchange. For this reason, atmospheric oxygen measurements can be used to constrain the global carbon cycle, especially oceanic uptake. However, accurately quantifying the small (~1-100 ppm) variations in O2 is analytically challenging due…

As part of the DENCHAR (Development and Evaluation of Novel Compact Hygrometer for Airborne Research) inter-comparison campaign in northern Germany in 2011, a commercial cavity ring-down spectroscopy (CRDS) based gas analyzer (G2401-m, Picarro Inc., US) was installed on a Learjet to measure atmospheric water vapor, CO2, CH4, and CO. The CRDS components were identical to those chosen for…

We report the determination of ammonia (NH3) diffusive sampling rates for six different designs of commercial
diffusive samplers (CEH ALPHA sampler, Gradko diffusion tube, Gradko DIFRAM-400, Passam ammonia sampler,
and ICS Maugeri Radiello radial sampler (blue and white turbulence barriers)), together with the validation
test results for a pumped sampler (CEH DELTA denuder). The…

In this paper, we present an innovative CH₄, δ¹³CH₄, and C₂H₆ instrument based on cavity ring-down spectroscopy (CRDS). The design and performance of the analyzer is presented in detail. The instrument is capable of precision of less than 1‰ on δ¹³CH₄ with 1 in. of averaging and about 0.1‰ in an hour. Using this…

The reasons for the early Holocene temperature discrepancy between northern hemispheric model simulations and paleoclimate reconstructions—known as the Holocene temperature conundrum—remain unclear. Using hydrogenisotopes of fluid inclusion water extracted from stalagmites from the Milandre Cave in Switzerland, we established a mid-latitude European mean annual temperature reconstruction…

A warming climate results in sea ice loss and impacts to the Arctic water cycle. The water isotope
parameter deuterium excess, a moisture source proxy, can serve as a tracer to help understand hydrological
changes due to sea ice loss. However, unlocking the sea ice change signal of isotopes from ice cores requires
understanding how sea ice changes impact deuterium excess, which…

During the day, hummingbirds quickly metabolize floral nectar to fuel high metabolic
demands, but are unable to feed at night. Though stored fat is the primary nocturnal metabolic
fuel, it has been suggested that hummingbirds store nectar in their crop to offset fat expenditure
in the night or to directly fuel their first foraging trip in the morning. We examine the use of
…

The effects of climate change appear to be amplified in mountains compared with lowland areas, with rapid changes in plant community composition, soil properties, and increased substrate for biological development following retreat of glaciers. Associated soil gaseous fluxes in alpine ecosystems contribute to the global balance of greenhouse gases, but methane and carbon dioxide soil fluxes…

Methane (CH₄) is a strong greenhouse gas with a global warming potential 23 times larger than that of carbon dioxide. Characterizing ecosystems as either sources or sinks for methane and their magnitudes informs on biosphere contributions to the global CH₄ budget and to warming of the atmosphere. We quantified methane fluxes for the first time in a neotropical alpine…

Greenhouse gas (GHG) emissions from rivers are a critical missing component of current global GHG models.
Their exclusion is mainly due to a lack of in-situ measurements and a poor understanding of the spatiotemporal
dynamics of GHG production and emissions, which prevents optimal model parametrization. We combined simultaneous
observations of porewater concentrations along…

The North China Plain has been identified as a global hotspot for ammonia (NH₃). To date, NH₃ surface observations in the region have mostly been obtained by passive samplers with a time resolution of weeks (e.g., AMoN-China), and few studies have been performed with fast-response instruments. Thus, the detailed temporal variations of NH₃ …

To improve our understanding of chlorine chemistry indoors, reactive chlorine species such as hydrogen chloride (HCl) must be analyzed using fast time-response measurement techniques. Although well studied outdoors, sources of HCl indoors are unknown. In this study, mixing ratios of gaseous HCl were measured at 0.5 Hz in the indoor environment using a cavity ring-down spectroscopy (CRDS)…

Formaldehyde (HCHO) and nitrogen dioxide (NO₂) often co-exist in urban environments at levels that are hazardous to health. There is a demand for a solution to the problem of their combined removal. In this paper, we investigate catalysts, adsorbents and composites for their removal efficiency (RE) toward HCHO and NO₂, in the context of creating a pollution control…

Atmospheric sulfate aerosols have important impacts on air quality, climate, and human and ecosystem health. However, current air-quality models generally underestimate the rate of conversion of sulfur dioxide (SO₂) to sulfate during severe haze pollution events, indicating that our understanding of sulfate formation chemistry is incomplete. This may arise because the air-quality…

A monoclonal antibody drug product (DP) manufacturing process was transferred to a different production site, where aseptic filling took place within an isolator that was sanitized using vapor phase hydrogen peroxide (VPHP). A quality-by-design approach was applied for study design to understand the impact of VPHP uptake in the isolator on DP quality. A combination of small-scale and…

Isolators are commonly used in filling operations of pharmaceutical products. To ensure an aseptic inner environment, isolators are regularly sterilized with vaporized hydrogen peroxide. However, despite extensive purging with air, some residual H₂O₂ remains within the isolator atmosphere and may thus end up in the liquid pharmaceutical drug product, which subsequently…

We developed regression models for designing rapid and effective H₂O₂ decontamination processes in the manufacturing of sterile drug products such as injectables. Decontamination, which is typically performed by using H₂O₂, is a critical changeover process used to establish a sterile environment for filling products. In the process, there is a =…

As part of manufacturing a sterile drug product, we quantified the impact of H₂O₂ sorption by polymers  on the duration of aeration in pharmaceutical decontamination. Five polymers, which are typically used as materials/parts in sterile isolators, were investigated: polyethylene, polyvinyl chloride, Silicone, polyoxymethylene (POM), and chlorosulfonated…

Carbon content constitutes a major fraction of atmospheric particulate matter (PM) and directly influences the earth’s climate and human health. The stable carbon isotope ratios (δ¹³C) can be used to track potential sources and atmospheric processes of carbonaceous aerosols. Previously, determination of δ¹³C was always conducted in offline carbonaceous aerosol samples…

Raindrops interact with water vapour in ambient air while sedimenting from the cloud base to the ground. They constantly exchange water molecules with the environment and, in sub-saturated air, they evaporate partially or entirely. The latter of these below-cloud processes is important for predicting the resulting surface rainfall amount. It also influences the boundary layer profiles of…

In older persons, muscle loss is accelerated during physical inactivity and hypoenergetic states, both of which are features of hospitalization. Protein supplementation may represent a strategy to offset the loss of muscle during inactivity, and enhance recovery on resumption of activity. We aimed to determine if protein supplementation, with proteins of substantially different quality,…

High-resolution data on a field scale is very important for improving our understanding of hydrological processes. This is particularly the case for water-demanding agricultural production systems such as rice paddies, for which water-saving strategies need to be developed. Here we report on the application of an in situ, automatic sampling system for high-resolution data on stable isotopes…

A fundamental challenge in plant physiology is independently determining the rates of gross O₂ production by photosynthesis and O2 consumption by respiration, photorespiration, and other processes. Previous studies on isolated chloroplasts or leaves have separately constrained net and gross O2 production (NOP and GOP, respectively) by labeling ambient O₂ with ^18…

Sumatra Squalls, organized bands of thunderstorms, are the dominant mesoscale convective systems during the intermonsoon and southwest monsoon seasons in Singapore. To understand how they affect precipitation isotopes, we monitored the δ value of precipitation daily and continuously (every second and integrated over 30 s) during all squalls in 2015. We found that precipitation δ18O values…

Catchment response to precipitation is often investigated using two-component isotope-based hydrograph separation, which quantifies the contribution of precipitation (i.e., event water Qe) or water from storage (i.e., pre-event water Qpe) to total discharge (Q) during storm events. In order to better understand streamflow-generating mechanisms, two-component hydrograph separation studies…

A total of 2 to 3 million tons of spring water flushes out from the foot of Mt. Fuji, the largest volcanic mountain in Japan. Based on the concept of piston flow transport, residence time of stored groundwater at Mt. Fuji was estimated at  ∼  15–30 years by the 36Cl ∕ Cl ratio (Tosaki et al., 2011). This range, however, represents the average residence time of groundwater that was mixed…

• The internal CO₂ gradient imposed by mesophyll conductance (gm) reduces substrate availability for C₃ photosynthesis. With several assumptions, estimates of gm can be made from coupled leaf gas exchange with isoflux analysis of carbon ∆¹³C‐gm and oxygen in CO₂, coupled with transpired water (H₂O) ∆¹⁸O‐gm to partition…

https://analyticalsciencejournals.onlinelibrary.wiley.com/doi/10.1002/rcm.9078
https://doi.org/10.1002/rcm.9078

Rationale: Oxygen and hydrogen isotopes are important…

Privacy curtain contamination, including with multidrug-resistant organisms, and the associated infection transmission risks have been well described; however, current approaches for addressing these risks and available guidance are limited. The present study describes the successful reduction of curtain contamination in five different units within a tertiary care hospital utilizing…

Agricultural peatlands are estimated to emit approximately one third of global greenhouse gas (GHG) emissions from croplands, but the temporal dynamics and controls of these emissions are poorly understood, particularly for nitrous oxide (N₂O). We used cavity ring-down spectroscopy and automated chambers in a drained agricultural peatland to measure over 70,000 individual N_2…

Spectroscopic instruments are becoming increasingly popular for measuring the isotopic composition and fluxes of a wide variety of gases in both field and laboratory experiments. The popularity of these instruments has created a need for automated multiplexers compatible with the equipment. While there are several such peripherals commercially available, they are currently limited to only a…

A general feature in the diurnal cycle of atmospheric ammonia (NH₃) concentrations is a morning spike that typically occurs around 07:00 to 10:00 (LST). Current hypotheses to explain this morning’s NH₃ increase remain elusive, and there is still no consensus whether traffic emissions are among the major sources of urban NH₃. Here, we confirmed that the NH…

The reduced economic and social activities during the Chinese Spring Festival provide a unique experiment to evaluate reductions in anthropogenic NH₃ emissions in China. However, quantifying this unique scenario is challenging as meteorology may mask the real changes in observed NH3 concentrations. Here, we applied a machine learning technique to decouple the effects of…

Ventilation is of primary concern for maintaining healthy indoor air quality and reducing the spread of airborne infectious disease, including COVID-19. In addition to building-level guidelines, increased attention is being placed on room-level ventilation. However, for many universities and schools, ventilation data on a room-byroom basis are not available for classrooms and other key…

Coastal wetlands play an important role in nitrogen removal and are a vital blue carbon sink. The produced methane (CH₄) in coastal wetlands has been recently identified as a possible carbon source for denitrification process, providing a significant contribution to coastal nitrogen cycling. However, the in-situ correlation between CH₄ emissions and denitrification…

Total gaseous chlorine (TCl_g) measurements can improve our understanding of unknown sources of Cl to the atmosphere. Existing techniques for measuring TCl_g have been limited to offline analysis of extracted filters and do not provide suitable temporal information on fast atmospheric process. We describe high time-resolution in-situ measurements of TCl_g by…

Reliable, sensitive, and widely available hydrogen chloride (HCl) measurements are important for understanding oxidation in many regions of the troposphere. We configured a commercial HCl cavity ring-down spectrometer (CRDS) for sampling HCl in the ambient atmosphere and developed validation techniques to characterize the measurement uncertainties. The CRDS makes fast, sensitive, and robust…