Selective ultra-trace atmospheric passive sampling of gaseous perfluoroalkyl carboxylic acids.

Acidic pollutants have long been known to have detrimental impacts on remote ecosystems. They have been subject to assessment through long-term monitoring with low cost methodologies, such as passive sampling. Atmospheric oxidation is becoming recognized as a source of persistent perfluorinated carboxylic acids (PFCAs) derived from volatile poly- and perfluorinated alkyl substance (PFAS) precursors.

Atmospheric fate and deposition of polyhalogenated carbazoles in urban environment.

Polyhalogenated carbazoles (PHCZs) are of emerging environmental concern due to their dioxin-like toxicity and widespread distribution in the aquatic environment. However, knowledge of the occurrence, fate, and impacts of PHCZs in the atmospheric environment is limited. The present study investigated air concentrations and atmospheric deposition of 11 PHCZs in Toronto, Canada, during the winter of 2024.

Particulate Matter and Total Volatile Organic Compound Emissions Following Surface Cleaning: Comparison of Cleaning Agents and Locations.

Cleaning activities are essential for maintaining hygiene in indoor environments but can significantly influence indoor air quality (IAQ). We investigated emissions of volatile organic compounds (VOCs) and particulate matter (PM) during cleaning events across various indoor settings including two laboratories, an office, and a residential bathroom, with room volumes ranging from 22 to 206 m and air changes rates (ACR) of 0.85-9.

Commercial kitchen operations produce a diverse range of gas-phase reactive nitrogen species.

Gas-phase reactive nitrogen species (N) are important drivers of indoor air quality. Cooking and cleaning are significant direct sources indoors, whose emissions will vary depending on activity and materials used. Commercial kitchens experience regular high volumes of both cooking and cleaning, making them ideal study locations for exploring emission factors from these sources.

Chemical Fate of Oils on Indoor Surfaces: Ozonolysis and Peroxidation.

Unsaturated triglycerides found in food and skin oils are reactive in ambient air. However, the chemical fate of such compounds has not been well characterized in genuine indoor environments. Here, we monitored the aging of oil coatings on glass surfaces over a range of environmental conditions, using mass spectrometry, nuclear magnetic resonance (NMR), and electron paramagnetic resonance (EPR) techniques.

Suppressor and calibration standard limitations in cation chromatography of ammonium and 10 alkylamines in atmospheric samples.

Ammonia (NH) and alkylamines are ubiquitous in the atmosphere and have been suggested to play important global roles through new particle formation and aerosol growth. In this work, we optimized an ion-chromatographic (IC) method to separate and quantify the ten most abundant atmospheric alkylamines with high selectivity and separation efficiency, using 4 μm packed columns and resin-based suppressors, alongside stabilizing amine standards. Modern resin suppressors operating on a gradient elution program affected the linear response of this IC technique.

A Rapid Derivatization for Quantitation of Perfluorinated Carboxylic Acids from Aqueous Matrices by Gas Chromatography-Mass Spectrometry.

Ultrashort-chain perfluorinated carboxylic acids (PFCAs) are receiving more attention due to their ever-increasing presence in the environment. Methods have been established for the analysis of short- and long-chain PFCAs, while robust quantitation of ultrashort-chain species is scarce. Here, we develop a novel derivatization method using diphenyl diazomethane for quantitation of C2-C14 PFCAs in aqueous matrices.

Indoor and outdoor air quality impacts of cooking and cleaning emissions from a commercial kitchen.

Gas and particulate emissions from commercial kitchens are important contributors to urban air quality. Not only are these emissions important for occupational exposure of kitchen staff, but they can also be vented to outdoors, causing uncertain health and environmental impacts. In this study, we chemically speciated volatile organic compounds and measured particulate matter mass concentrations in a well-ventilated commercial kitchen for two weeks, including during typical cooking and cleaning operations.

Emerging investigator series: an instrument to measure and speciate the total reactive nitrogen budget indoors: description and field measurements.

Reactive nitrogen species (N), defined here as all N-containing compounds except N and NO, have been shown to be important drivers for indoor air quality. Key N species include NO (NO + NO), HONO and NH, which are known to have detrimental health effects. In addition, other N species that are not traditionally measured may be important chemical actors for indoor transformations ( amines).

Near-source hypochlorous acid emissions from indoor bleach cleaning.

Cleaning surfaces with sodium hypochlorite (NaOCl) bleach can lead to high levels of gaseous chlorine (Cl) and hypochlorous acid (HOCl); these have high oxidative capacities and are linked to respiratory issues. We developed a novel spectral analysis procedure for a cavity ring-down spectroscopy (CRDS) hydrogen peroxide (HO) analyzer to enable time-resolved (3 s) HOCl quantification. We measured HOCl levels in a residential bathroom while disinfecting a bathtub and sink, with a focus on spatial and temporal trends to improve our understanding of exposure risks during bleach use.

Elevated levels of chloramines and chlorine detected near an indoor sports complex.

Chloramines (NHCl, NHCl, and NCl) are toxic compounds that can be created during the use of bleach-based disinfectants that contain hypochlorous acid (HOCl) and the hypochlorite ion (OCl) as their active ingredients. Chloramines can then readily transfer from the aqueous-phase to the gas-phase. Atmospheric chemical ionization mass spectrometry using iodide adduct chemistry (I-CIMS) made observations across two periods (2014 and 2016) at an urban background site on the University of Leicester campus (Leicester, UK).

Reactive Chlorine Emissions from Cleaning and Reactive Nitrogen Chemistry in an Indoor Athletic Facility.

Indoor gas-phase radical sources are poorly understood but expected to be much different from outdoors. Several potential radical sources were measured in a windowless, light-emitting diode (LED)-lit room in a college athletic facility over a 2 week period. Alternating measurements between the room air and the supply air of the heating, ventilation, and air-conditioning system allowed an assessment of sources.

Exploring controls on perfluorocarboxylic acid (PFCA) gas-particle partitioning using a model with observational constraints.

The atmospheric fate of perfluorocarboxylic acids (PFCAs) has attracted much attention in recent decades due to the role of the atmosphere in global transport of these persistent chemicals. There is a gap in our understanding of gas-particle partitioning, limited by availability of reliable atmospheric measurements, partitioning properties, and models of gas-particle interactions. The gas-particle equilibrium phase partitioning of C2-C16 PFCAs in the atmosphere were modeled here by taking account of both deprotonation and phase partitioning equilibria among air, aerosol liquid water, and particulate water-insoluble organic matter using a range of available PFCA partitioning properties.

Emerging investigator series: ozone uptake by urban road dust and first evidence for chlorine activation during ozone uptake by agro-based anti-icer: implications for wintertime air quality in high-latitude urban environments.

High-latitude urban regions provide a unique and complex range of environmental surfaces for uptake of trace pollutant gases, including winter road maintenance materials (, gravel, rock salts, and anti-icer, a saline solution applied to roads during winter). In an effort to reduce the negative environmental and economic impacts of road salts, many municipalities have turned to agro-based anti-icing materials that are rich in organic material. To date, the reactivity of both anti-icer and saline road dust with pollutant gases remain unexplored, which limits our ability to assess the potential impacts of these materials on air quality in high-latitude regions.

Hydrogen chloride (HCl) at ground sites during CalNex 2010 and insight into its thermodynamic properties.

Gas phase hydrogen chloride (HCl) was measured at Pasadena and San Joaquin Valley (SJV) ground sites in California during May and June 2010 as part of the CalNex study. Observed mixing ratios were on average 0.83 ppbv at Pasadena, ranging from below detection limit (0.

A boron dipyrromethene (BODIPY) based probe for selective passive sampling of atmospheric nitrous acid (HONO) indoors.

People spend up to 90% of their time indoors, and yet our understanding of indoor air quality and the chemical processes driving it are poorly understood, despite levels of key pollutants typically being higher indoors compared to outdoors. Nitrous acid (HONO) is a species that drives these indoor chemical processes, with potentially detrimental health effects. In this work, a BODIPY-based probe was synthesized with the aim of developing the first selective passive sampler for atmospheric HONO.

Hydrogen Peroxide Emission and Fate Indoors during Non-bleach Cleaning: A Chamber and Modeling Study.

Activities such as household cleaning can greatly alter the composition of air in indoor environments. We continuously monitored hydrogen peroxide (HO) from household non-bleach surface cleaning in a chamber designed to simulate a residential room. Mixing ratios of up to 610 ppbv gaseous HO were observed following cleaning, orders of magnitude higher than background levels (sub-ppbv).

Selective decontamination of the reactive air pollutant nitrous acid node-linker cooperativity in a metal-organic framework.

Nitrous acid (HONO) is a reservoir of NO and an emerging pollutant having direct impacts on air quality, both in- and outdoors, as well as on human health. In this work, the amine-functionalized metal-organic framework (MOF), UiO-66-NH, was investigated due to its potential to selectively decontaminate nitrous acid at environmentally relevant concentrations. UiO-66-NH proved to be effective in the removal of nitrous acid from a continuous gaseous stream.

Role of location, season, occupant activity, and chemistry in indoor ozone and nitrogen oxide mixing ratios.

Understanding the oxidizing environment indoors is important for predicting indoor air quality and its impact on human health. We made continuous time-resolved measurements (30 s) of several oxidants and oxidant precursors (collectively referred to as oxidant*): ozone (O3), nitric oxide (NO), and NO2* - the sum of nitrogen dioxide (NO2) and nitrous acid (HONO). These species were measured in three indoor environments - an occupied residence, a chemistry laboratory, and an academic office - in Syracuse, New York, during two seasons in 2017 and 2018.

Formation and emission of hydrogen chloride in indoor air.

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.

Time-Resolved Measurements of Nitric Oxide, Nitrogen Dioxide, and Nitrous Acid in an Occupied New York Home.

Indoor oxidizing capacity in occupied residences is poorly understood. We made simultaneous continuous time-resolved measurements of ozone (O), nitric oxide (NO), nitrogen dioxide (NO), and nitrous acid (HONO) for two months in an occupied detached home with gas appliances in Syracuse, NY. Indoor NO and HONO mixing ratios were higher than those outdoors, whereas O was much lower (sub-ppbv) indoors.

Development of a gas phase source for perfluoroalkyl acids to examine atmospheric sampling methods.

An inability to produce environmentally relevant gaseous mixing ratios of perfluoroalkyl acids (PFAAs), ubiquitous global contaminants, limits the analytical reliability of atmospheric chemists to make accurate gas and particulate measurements that are demonstrably free of interferences due to sampling artefacts. A gas phase source for PFAAs based on the acid displacement mechanism using perfluoropropionate (PFPrA), perfluorobutanoate (PFBA), perfluorohexanoate (PFHxA), and perfluorooctanoate (PFOA) has been constructed. The displacement efficiency of gas phase perfluorocarboxylic acids (PFCAs) is inversely related to chain length.

An Atmospheric Constraint on the NO2 Dependence of Daytime Near-Surface Nitrous Acid (HONO).

Recent observations suggest a large and unknown daytime source of nitrous acid (HONO) to the atmosphere. Multiple mechanisms have been proposed, many of which involve chemistry that reduces nitrogen dioxide (NO2) on some time scale. To examine the NO2 dependence of the daytime HONO source, we compare weekday and weekend measurements of NO2 and HONO in two U.

Insights into secondary organic aerosol formation mechanisms from measured gas/particle partitioning of specific organic tracer compounds.

In situ measurements of organic compounds in both gas and particle phases were made with a thermal desorption aerosol gas chromatography (TAG) instrument. The gas/particle partitioning of phthalic acid, pinonaldehyde, and 6,10,14-trimethyl-2-pentadecanone is discussed in detail to explore secondary organic aerosol (SOA) formation mechanisms. Measured fractions in the particle phase (f(part)) of 6,10,14-trimethyl-2-pentadecanone were similar to those expected from the absorptive gas/particle partitioning theory, suggesting that its partitioning is dominated by absorption processes.

Vertically resolved measurements of nighttime radical reservoirs in Los Angeles and their contribution to the urban radical budget.

Photolabile nighttime radical reservoirs, such as nitrous acid (HONO) and nitryl chloride (ClNO(2)), contribute to the oxidizing potential of the atmosphere, particularly in early morning. We present the first vertically resolved measurements of ClNO(2), together with vertically resolved measurements of HONO. These measurements were acquired during the California Nexus (CalNex) campaign in the Los Angeles basin in spring 2010.