Evaluating the Laboratory Performance of Pellet-Fueled Semigasifier Cookstoves.

This study examines three representative semigasifier cookstove models each burning four types of pelletized-biomass fuel (hardwood, peanut hull, rice husk, and wheat straw) using the International Organization for Standardization (ISO) 19867-1:2018 protocol. ISO tier ratings for fine particulate matter (PM) and carbon monoxide (CO) emissions ranged 1-4 and 2-5 (where 5 = cleanest), respectively, suggesting that pellet-fueled cookstoves may provide substantial emissions reductions, dependent upon stove/fuel matching and operation, over other biomass-fueled cooking alternatives. PM emission factors based on useful energy delivered (EF) varied by up to 25-fold, and organic and elemental carbon (OC and EC) EF values respectively varied by >200- and ∼100-fold, reflecting complex variability in PM composition.

Human Monocyte-Derived Macrophages Demonstrate Distinct Responses to Ambient Particulate Matter in a Polarization State- and Particle Seasonality-Specific Manner.

Macrophages are professional phagocytic immune cells that, following activation, polarize on a spectrum between the proinflammatory M1 and the proresolution M2 states. Macrophages have further been demonstrated to retain plasticity, allowing for the reprogramming of their polarization states following exposure to new stimuli. Particulate matter (PM) has been repeatedly shown to modify macrophage function and polarization while also inducing worsening respiratory infection morbidity and mortality.

Ethylene Oxide: An Air Contaminant of Concern.

Ethylene oxide (EtO) is a colorless, flammable, reactive gas commonly used for sterilization and chemical manufacturing. It has become a contaminant of concern for the United States Environmental Protection Agency (USEPA) due to an assessment of its toxicity, which found that EtO is more potent than had been previously understood and which also revised the weight-of-evidence classification of EtO from "probably carcinogenic" to "carcinogenic to humans". With the revised toxicity assessment came findings of increased cancer risk to communities near some facilities that emit EtO to ambient air, including communities with environmental justice (EJ) concerns.

Quantifying functional group compositions of household fuel-burning emissions.

Globally, billions of people burn fuels indoors for cooking and heating, which contributes to millions of chronic illnesses and premature deaths annually. Additionally, residential burning contributes significantly to black carbon emissions, which have the highest global warming impacts after carbon dioxide and methane. In this study, we use Fourier transform infrared spectroscopy (FTIR) to analyze fine-particulate emissions collected on Teflon membrane filters from 15 cookstove types and 5 fuel types.

Burn pit-related smoke causes developmental and behavioral toxicity in zebrafish: Influence of material type and emissions chemistry.

Combustion of mixed materials during open air burning of refuse or structural fires in the wildland urban interface produces emissions that worsen air quality, contaminate rivers and streams, and cause poor health outcomes including developmental effects. The zebrafish, a freshwater fish, is a useful model for quickly screening the toxicological and developmental effects of agents in such species and elicits biological responses that are often analogous and predictive of responses in mammals. The purpose of this study was to compare the developmental toxicity of smoke derived from the burning of 5 different burn pit-related material types (plywood, cardboard, plastic, a mixture of the three, and the mixture plus diesel fuel as an accelerant) in zebrafish larvae.

Salmonella T3SS effector SseK1 arginine-glycosylates the two-component response regulator OmpR to alter bile salt resistance.

Type III secretion system (T3SS) effector proteins are primarily recognized for binding host proteins to subvert host immune response during infection. Besides their known host target proteins, several T3SS effectors also interact with endogenous bacterial proteins. Here we demonstrate that the Salmonella T3SS effector glycosyltransferase SseK1 glycosylates the bacterial two-component response regulator OmpR on two arginine residues, R15 and R122.

Development of Volatility Distributions for Organic Matter in Biomass Burning Emissions.

The volatility distribution of organic emissions from biomass burning and other combustion sources can determine their atmospheric evolution due to partitioning/aging. The gap between measurements and models predicting secondary organic aerosol has been partially attributed to the absence of semi- and intermediate volatility organic compounds (S/I-VOC) in models and measurements. However, S/I-VOCs emitted from these sources and typically quantified using the volatility basis framework (VBS) are not well understood.

Arginine glycosylation regulates UDP-GlcNAc biosynthesis in Salmonella enterica.

The Salmonella enterica SseK1 protein is a type three secretion system effector that glycosylates host proteins during infection on specific arginine residues with N-acetyl glucosamine (GlcNAc). SseK1 also Arg-glycosylates endogenous bacterial proteins and we thus hypothesized that SseK1 activities might be integrated with regulating the intrabacterial abundance of UPD-GlcNAc, the sugar-nucleotide donor used by this effector. After searching for new SseK1 substrates, we found that SseK1 glycosylates arginine residues in the dual repressor-activator protein NagC, leading to increased DNA-binding affinity and enhanced expression of the NagC-regulated genes glmU and glmS.

Chemistry, lung toxicity and mutagenicity of burn pit smoke-related particulate matter.

Background: Open burning of anthropogenic sources can release hazardous emissions and has been associated with increased prevalence of cardiopulmonary health outcomes. Exposure to smoke emitted from burn pits in military bases has been linked with respiratory illness among military and civilian personnel returning from war zones. Although the composition of the materials being burned is well studied, the resulting chemistry and potential toxicity of the emissions are not.

Cookstove Emissions and Performance Evaluation Using a New ISO Protocol and Comparison of Results with Previous Test Protocols.

In 2018, the International Organization for Standardization (ISO) 19867-1 "Harmonized laboratory test protocols" were released for establishing improved quality and comparability for data on cookstove air pollutant emissions, efficiency, safety, and durability. This is the first study that compares emissions [carbon dioxide, carbon monoxide, total hydrocarbons, methane, nitrogen oxides, fine particulate matter (PM), organic carbon, elemental carbon, and ultrafine particles] and efficiency data between the ISO protocol and the Water Boiling Test (WBT). The study examines six stove/fuel combinations [liquefied petroleum gas (LPG), pellet, wood fan, wood rocket, three stone fire, and charcoal] tested in the same US EPA laboratory.

Bacterial community analysis of purulent material from liver abscesses of crossbred cattle and Holstein steers fed finishing diets with or without tylosin.

Liver abscesses in feedlot cattle are polymicrobial infections. Culture-based studies have identified Fusobacterium necrophorum as the primary causative agent, but a number of other bacterial species are frequently isolated. The incidence of liver abscesses is highly variable and is affected by a number of factors, including cattle type.

Censoring Trace-Level Environmental Data: Statistical Analysis Considerations to Limit Bias.

Trace-level environmental data typically include values near or below detection and quantitation thresholds where health effects may result from low-concentration exposures to one chemical over time or to multiple chemicals. In a cook stove case study, bias in dibenzo[a,h]anthracene concentration means and standard deviations (SDs) was assessed following censoring at thresholds for selected analysis approaches: substituting threshold/2, maximum likelihood estimation, robust regression on order statistics, Kaplan-Meier, and omitting censored observations. Means and SDs for gas chromatography-mass spectrometry-determined concentrations were calculated after censoring at detection and calibration thresholds, 17% and 55% of the data, respectively.

Chemical composition, structures, and light absorption of N-containing aromatic compounds emitted from burning wood and charcoal in household cookstoves.

N-containing aromatic compounds (NACs) are an important group of light-absorbing molecules in the atmosphere. They are often observed in combustion emissions, but their chemical formulas and structural characteristics remain uncertain. In this study, red oak wood and charcoal fuels were burned in cookstoves using the standard water boiling test (WBT) procedure.

An assessment of important SPECIATE profiles in the EPA emissions modeling platform and current data gaps.

The United States (US) Environmental Protection Agency (EPA)'s SPECIATE database contains speciated particulate matter (PM) and volatile organic compound (VOC) emissions profiles. Emissions profiles from anthropogenic combustion, industry, wildfires, and agricultural sources among others are key inputs for creating chemically-resolved emissions inventories for air quality modeling. While the database and its use for air quality modeling are routinely updated and evaluated, this work sets out to systematically prioritize future improvements and communicate speciation data needs to the research community.

A Fulvic Acid-like Substance Participates in the Pro-inflammatory Effects of Cigarette Smoke and Wood Smoke Particles.

We tested the postulates that (1) a fulvic acid (FA)-like substance is included in cigarette smoke and wood smoke particles (WSP) and (2) cell exposure to this substance results in a disruption of iron homeostasis, associated with a deficiency of the metal and an inflammatory response. The fluorescence excitation-emission matrix spectra of the water-soluble components of cigarette smoke condensate and WSP (Cig-WS and Wood-WS) approximated those for the standard reference materials, Suwanee River and Nordic fulvic acids (SRFA and NFA). Fourier transform infrared spectra for the FA fraction of cigarette smoke and WSP (Cig-FA and Wood-FA), SRFA, and NFA also revealed significant similarities (O-H bond in alcohols, phenols, and carboxylates, C═O in ketones, aldehydes, and carboxylates, and a significant carboxylate content).

An intra-bacterial activity for a T3SS effector.

Many Gram-negative bacterial pathogens interact with mammalian cells by using type III secretion systems (T3SS) to inject virulence proteins into host cells. A subset of these injected protein 'effectors' are enzymes that inhibit the function of host proteins by catalyzing the addition of unusual post-translational modifications. The E.

Carbonaceous Particulate Matter Emitted from a Pellet-Fired Biomass Boiler.

Biomass pellets are a source of renewable energy; although, the air pollution and exposure risks posed by the emissions from burning pellets in biomass boilers (BBs) are uncertain. The present study examines the organic species in fine particle matter (PM) emissions from an BB firing switchgrass (SwG) and hardwood (HW) biomass pellets using different test cycles. The organic and elemental carbon (OC and EC) content and select semivolatile organic compounds (SVOCs) in filter-collected PM were identified and quantified using thermal-optical analysis and gas chromatography-mass spectrometry (GC-MS), respectively.

Composition and light absorption of N-containing aromatic compounds in organic aerosols from laboratory biomass burning.

This study seeks to understand the compositional details of N-containing aromatic compounds (NACs) emitted during biomass burning (BB) and their contribution to light-absorbing organic carbon (OC), also termed brown carbon (BrC). Three laboratory BB experiments were conducted with two U.S.

The role of fuel type and combustion phase on the toxicity of biomass smoke following inhalation exposure in mice.

The characteristics of wildland fire smoke exposures which initiate or exacerbate cardiopulmonary conditions are unclear. We previously reported that, on a mass basis, lung toxicity associated with particulate matter (PM) from flaming smoke aspirated into mouse lungs is greater than smoldering PM. In this study, we developed a computer-controlled inhalation system which can precisely control complex biomass smoke emissions from different combustion conditions.

Structural basis for arginine glycosylation of host substrates by bacterial effector proteins.

The bacterial effector proteins SseK and NleB glycosylate host proteins on arginine residues, leading to reduced NF-κB-dependent responses to infection. Salmonella SseK1 and SseK2 are E. coli NleB1 orthologs that behave as NleB1-like GTs, although they differ in protein substrate specificity.

Light absorption of organic carbon and its sources at a southeastern U.S. location in summer.

Light-absorbing organic carbon (OC), also referred to as "brown carbon" (BrC), has been intensively investigated in atmospheres impacted by biomass burning. However, other BrC sources (e.g.

Immunization With Skp Delivered on Outer Membrane Vesicles Protects Mice Against Enterotoxigenic Challenge.

Outer membrane vesicles (OMVs) are promising vaccine components because they combine antigen and adjuvant in a single formulation. Detoxified strains that express penta-acylated lipid A retain OMV immunogenicity but with reduced reactogenicity. We have previously shown that a recombinant form of the enterotoxigenic (ETEC) 17 kilodalton protein (Skp) protects mice in a pulmonary challenge model, when fused to the glutathione-S-transferase (GST) epitope and combined with cholera toxin.