Photocatalysis of Adsorbed Catechol on Degussa P25 TiO at the Air-Solid Interface.

Semiconductor photocatalysis with commercial TiO (Degussa P25) has shown significant potential in water treatment of organic pollutants. However, the photoinduced reactions of adsorbed catechol, a phenolic air pollutant from biomass burning and combustion emissions, at the air-solid interface of TiO remain unexplored. Herein we examine the photocatalytic decay of catechol in the presence of water vapor, which acts as an electron acceptor.

Environmental sustainability in gynecologic oncology.

Climate change is a complex, global issue that is impacting human health in various ways, with healthcare being a significant contributor to carbon emissions in the United States. This review discusses the environmental impact of important aspects of gynecologic oncology care, including surgery, anesthesia care, radiology, chemotherapy, and radiation oncology. Operating room energy and material use is highlighted, with a focus on the environmental impact of robotic surgery.

In Situ Electrochemistry of Formate on Cu Thin Films Using ATR-FTIR Spectroscopy and X-ray Photoelectron Spectroscopy.

Formate (HCOO) is the most dominant intermediate identified during carbon dioxide electrochemical reduction (COER). While previous studies showed that copper (Cu)-based materials that include Cu(0), CuO, and CuO are ideal catalysts for COER, challenges to scalability stem from low selectivity and undesirable products in the -1.0-1.

Reactivity of aminophenols in forming nitrogen-containing brown carbon from iron-catalyzed reactions.

Nitrogen-containing organic carbon (NOC) in atmospheric particles is an important class of brown carbon (BrC). Redox active NOC like aminophenols received little attention in their ability to form BrC. Here we show that iron can catalyze dark oxidative oligomerization of o- and p-aminophenols under simulated aerosol and cloud conditions (pH 1-7, and ionic strength 0.

Oxidation of Phenolic Aldehydes by Ozone and Hydroxyl Radicals at the Air-Solid Interface.

Biomass burning emissions contain abundant phenolic aldehydes (e.g., syringaldehyde, vanillin, and 4-hydroxybenaldehyde) that are oxidized during atmospheric transport, altering the physicochemical properties of particulates.

Oxidation of Catechols at the Air-Water Interface by Nitrate Radicals.

Abundant substituted catechols are emitted to, and created in, the atmosphere during wildfires and anthropogenic combustion and agro-industrial processes. While ozone (O) and hydroxyl radicals (HO) efficiently react in a 1 μs contact time with catechols at the air-water interface, the nighttime reactivity dominated by nitrate radicals (NO) remains unexplored. Herein, online electrospray ionization mass spectrometry (OESI-MS) is used to explore the reaction of NO(g) with a series of representative catechols (catechol, pyrogallol, 3-methylcatechol, 4-methylcatechol, and 3-methoxycatechol) on the surface of aqueous microdroplets.

Chemical State of Potassium on the Surface of Iron Oxides: Effects of Potassium Precursor Concentration and Calcination Temperature.

Potassium is used extensively as a promoter with iron catalysts in Fisher-Tropsch synthesis, water-gas shift reactions, steam reforming, and alcohol synthesis. In this paper, the identification of potassium chemical states on the surface of iron catalysts is studied to improve our understanding of the catalytic system. Herein, potassium-doped iron oxide (α-FeO) nanomaterials are synthesized under variable calcination temperatures (400-800 °C) using an incipient wetness impregnation method.

Interfacial Oxidative Oligomerization of Catechol.

The heterogeneous reaction between thin films of catechol exposed to O(g) creates hydroxyl radicals (HO) in situ, which in turn generate semiquinone radical intermediates in the path to form heavier polyhydroxylated biphenyl, terphenyl, and triphenylene products. Herein, the alteration of catechol aromatic surfaces and their chemical composition are studied during the heterogeneous oxidation of catechol films by O(g) molar ratios ≥ 230 ppbv at variable relative humidity levels (0% ≤ RH ≤ 90%). Fourier transform infrared micro-spectroscopy, atomic force microscopy, electrospray ionization mass spectrometry, and reverse-phase liquid chromatography with UV-visible and mass spectrometry detection provide new physical insights into understanding the surface reaction.

Surface Oxidation of Phenolic Aldehydes: Fragmentation, Functionalization, and Coupling Reactions.

Substantial amounts of phenolic aldehydes, represented by the structures of syringaldehyde, vanillin, and 4-hydroxybenzaldehyde, are emitted to the atmosphere during biomass burning. The oxidative transformation of phenolic aldehydes during atmospheric transport has the potential to modify the physicochemical properties of particulates, which play a vital role in Earth's climate and human health. Herein, thin solid films made of syringaldehyde, vanillin, and 4-hydroxybenzaldehyde are oxidized in contact with O(g) under a relative humidity of 74% representative of average global conditions.

Characteristics and health effects of particulate matter emitted from a waste sorting plant.

Solid waste components can be recycled in waste paper and cardboard sorting plants (WPCSP) through a multistep process. This work collected 15 samples every six days from each of the 9 points selected to study the processes taking place in a WPCSP (135 particulate matter samples total). Examining the concentration and size fraction of particulate matter (i.

Characteristics and assessing biological risks of airborne bacteria in waste sorting plant.

Examining the concentration and types of airborne bacteria in waste paper and cardboard sorting plants (WPCSP) is an urgent matter to inform policy makers about the health impacts on exposed workers. Herein, we collected 20 samples at 9 points of a WPCSP every 6 winter days, and found that the most abundant airborne bacteria were positively and negatively correlated to relative humidity and temperature, respectively. The most abundant airborne bacteria (in units of CFU m) were: Staphylococcus sp.

Aqueous Photochemistry of 2-Oxocarboxylic Acids: Evidence, Mechanisms, and Atmospheric Impact.

Atmospheric organic aerosols play a major role in climate, demanding a better understanding of their formation mechanisms by contributing multiphase chemical reactions with the participation of water. The sunlight driven aqueous photochemistry of small 2-oxocarboxylic acids is a potential major source of organic aerosol, which prompted the investigations into the mechanisms of glyoxylic acid and pyruvic acid photochemistry reviewed here. While 2-oxocarboxylic acids can be contained or directly created in the particles, the majorities of these abundant and available molecules are in the gas phase and must first undergo the surface uptake process to react in, and on the surface, of aqueous particles.

Modes of Transmission of Severe Acute Respiratory Syndrome-Coronavirus-2 (SARS-CoV-2) and Factors Influencing on the Airborne Transmission: A Review.

The multiple modes of SARS-CoV-2 transmission including airborne, droplet, contact, and fecal-oral transmissions that cause coronavirus disease 2019 (COVID-19) contribute to a public threat to the lives of people worldwide. Herein, different databases are reviewed to evaluate modes of transmission of SARS-CoV-2 and study the effects of negative pressure ventilation, air conditioning system, and related protection approaches of this virus. Droplet transmission was commonly reported to occur in particles with diameter >5 µm that can quickly settle gravitationally on surfaces (1-2 m).

An overview of the effect of bioaerosol size in coronavirus disease 2019 transmission.

The fast spread of coronavirus disease 2019 (COVID-19) constitutes a worldwide challenge to the public health, educational and trade systems, affecting the overall well-being of human societies. The high transmission and mortality rates of this virus, and the unavailability of a vaccine or treatment, resulted in the decision of multiple governments to enact measures of social distancing. Such measures can reduce the exposure to bioaerosols, which can result in pathogen deposition in the respiratory tract of the host causing disease and an immunological response.

Application of a Small Unmanned Aerial System to Measure Ammonia Emissions from a Pilot Amine-CO Capture System.

The quantification of atmospheric gases with small unmanned aerial systems (sUAS) is expanding the ability to safely perform environmental monitoring tasks and quickly evaluate the impact of technologies. In this work, a calibrated sUAS is used to quantify the emissions of ammonia (NH) gas from the exit stack a 0.1 MWth pilot-scale carbon capture system (CCS) employing a 5 M monoethanolamine (MEA) solvent to scrub CO from coal combustion flue gas.

Dark Iron-Catalyzed Reactions in Acidic and Viscous Aerosol Systems Efficiently Form Secondary Brown Carbon.

Iron-driven secondary brown carbon formation reactions from water-soluble organics in cloud droplets and aerosols create insoluble and soluble products of emerging atmospheric importance. This work shows, for the first time, results on dark iron-catalyzed polymerization of catechol forming insoluble black polycatechol particles and colored water-soluble oligomers under conditions characteristic of viscous multicomponent aerosol systems with relatively high ionic strength ( = 1-12 ) and acidic pH (∼2). These systems contain ammonium sulfate (AS)/nitrate (AN) and C3-C5 dicarboxylic acids, namely, malonic, malic, succinic, and glutaric acids.

Oxidation of Phenolic Aldehydes by Ozone and Hydroxyl Radicals at the Air-Water Interface.

Biomass burning releases highly reactive methoxyphenols into the atmosphere, which can undergo heterogeneous oxidation and act as precursors for secondary organic aerosol (SOA) formation. Understanding the reactivity of such methoxyphenols at the air-water interface is a matter of major atmospheric interest. Online electrospray ionization mass spectrometry (OESI-MS) is used here to study the oxidation of two methoxyphenols among three phenolic aldehydes, 4-hydroxybenzaldehyde, vanillin, and syringaldehyde, on the surface of water.

Production of Singlet Oxygen (O) during the Photochemistry of Aqueous Pyruvic Acid: The Effects of pH and Photon Flux under Steady-State O(aq) Concentration.

The photochemistry of pyruvic acid (PA) in aqueous atmospheric particles contributes to the production of secondary organic aerosols. This work investigates the fate of ketyl and acetyl radicals produced during the photolysis (λ ≥ 305 nm) of 5-100 mM PA under steady state [O(aq)] = 260 μM (1.0 ≤ pH ≤ 4.

Crystal structure of zymonic acid and a redetermination of its precursor, pyruvic acid.

The structure of zymonic acid (systematic name: 4-hy-droxy-2-methyl-5-oxo-2,5-di-hydro-furan-2-carb-oxy-lic acid), CHO, which had previously eluded crystallographic determination, is presented here for the first time. It forms by intra-molecular condensation of parapyruvic acid, which is the product of aldol condensation of pyruvic acid. A redetermination of the crystal structure of pyruvic acid (systematic name: 2-oxo-propanoic acid), CHO, at low temperature (90 K) and with increased precision, is also presented [for the previous structure, see: Harata (1977 ▸).

Intercomparison of Small Unmanned Aircraft System (sUAS) Measurements for Atmospheric Science during the LAPSE-RATE Campaign.

Small unmanned aircraft systems (sUAS) are rapidly transforming atmospheric research. With the advancement of the development and application of these systems, improving knowledge of best practices for accurate measurement is critical for achieving scientific goals. We present results from an intercomparison of atmospheric measurement data from the Lower Atmospheric Process Studies at Elevation-a Remotely piloted Aircraft Team Experiment (LAPSE-RATE) field campaign.

Using a Balloon-Launched Unmanned Glider to Validate Real-Time WRF Modeling.

The use of small unmanned aerial systems (sUAS) for meteorological measurements has expanded significantly in recent years. SUAS are efficient platforms for collecting data with high resolution in both space and time, providing opportunities for enhanced atmospheric sampling. Furthermore, advances in mesoscale weather research and forecasting (WRF) modeling and graphical processing unit (GPU) computing have enabled high resolution weather modeling.

The Effects of Reactant Concentration and Air Flow Rate in the Consumption of Dissolved O₂ during the Photochemistry of Aqueous Pyruvic Acid.

The sunlight photochemistry of the organic chromophore pyruvic acid (PA) in water generates ketyl and acetyl radicals that contribute to the production and processing of atmospheric aerosols. The photochemical mechanism is highly sensitive to dissolved oxygen content, [O₂()], among other environmental conditions. Thus, herein we investigate the photolysis (λ ≥ 305 nm) of 10⁻200 mM PA at pH 1.

Photocatalytic Activity: Experimental Features to Report in Heterogeneous Photocatalysis.

Heterogeneous photocatalysis is a prominent area of research with major applications in solar energy conversion, air pollution mitigation, and removal of contaminants from water. A large number of scientific papers related to the photocatalysis field and its environmental applications are published in different journals specializing in materials and nanomaterials. However, many problems exist in the conception of papers by authors unfamiliar with standard characterization methods of photocatalysts as well as with the procedures needed to determine photocatalytic activities based on the determination of "apparent quantum efficiencies" within a wavelength interval or "apparent quantum yields" in the case of using monochromatic light.

Cross Photoreaction of Glyoxylic and Pyruvic Acids in Model Aqueous Aerosol.

Aerosols of variable composition, size, and shape are associated with public health concerns as well as with light-particle interactions that play a role in the energy balance of the atmosphere. Photochemical reactions of 2-oxocarboxylic acids in the aqueous phase are now known to contribute to the total secondary organic aerosol (SOA) budget. This work explores the cross reaction of glyoxylic acid (GA) and pyruvic acid (PA) in water, the two most abundant 2-oxocarboxylic acids in the atmosphere, under solar irradiation and dark thermal aging steps.

Enhanced Acidity of Acetic and Pyruvic Acids on the Surface of Water.

Understanding the acid-base behavior of carboxylic acids on aqueous interfaces is a fundamental issue in nature. Surface processes involving carboxylic acids such as acetic and pyruvic acids play roles in (1) the transport of nutrients through cell membranes, (2) the cycling of metabolites relevant to the origin of life, and (3) the photooxidative processing of biogenic and anthropogenic emissions in aerosols and atmospheric waters. Here, we report that 50% of gaseous acetic acid and pyruvic acid molecules transfer a proton to the surface of water at pH 2.