We describe a novel biosafety aerosol chamber equipped with state-of-the-art instrumentation for bubble-bursting aerosol generation, size distribution measurement, and condensation-growth collection to minimize sampling artifacts when measuring virus infectivity in aerosol particles. Using this facility, we investigated the effect of relative humidity (RH) in very clean air without trace gases (except ∼400 ppm CO) on the preservation of influenza A virus (IAV) infectivity in saline aerosol particles. We characterized infectivity in terms of 99%-inactivation time, , a metric we consider most relevant to airborne virus transmission.
View Article and Find Full Text PDFBlack carbon (BC) and brown carbon (BrC) are light-absorbing carbonaceous aerosol components that can contribute to radiative forcing and thus affect the climate. In this study, we focus on the modification of aerosol optical properties associated with BrC emissions from biomass burning. BrC is simulated with the introduction of three new species in the three-dimensional chemical transport model PMCAMx-SR, two primary-absorbing (inert and reactive BrC) species, and one "photobleached" BrC species.
View Article and Find Full Text PDFThis paper addresses the challenges of calibrating low-cost electrochemical sensor systems for air quality monitoring. The proliferation of pollutants in the atmosphere necessitates efficient monitoring systems, and low-cost sensors offer a promising solution. However, issues such as drift, cross-sensitivity, and inter-unit consistency have raised concerns about their accuracy and reliability.
View Article and Find Full Text PDFOrganic compounds constitute a substantial part of atmospheric particulate matter not only in terms of mass concentration but also in terms of distinct functional groups. The glass transition temperature provides an indirect way to investigate the phase state of the organic compounds, playing a crucial role in understanding their behavior and influence on aerosol processes. Molecular dynamics (MD) simulations were implemented here to predict the glass transition temperature () of atmospherically relevant organic compounds as well as the influence of their functional groups and length of their carbon chain.
View Article and Find Full Text PDFExposure to wildfire smoke and dust can severely affect air quality and health. Although particulate matter (PM) levels and exposure are well-established metrics linking to health outcomes, they do not consider differences in particle toxicity or deposition location in the respiratory tract (RT). Usage of the oxidative potential (OP) exposure may further shape our understanding on how different pollution events impact health.
View Article and Find Full Text PDFPellet combustion in residential heating stoves has increased globally during the last decade. Despite their high combustion efficiency, the widespread use of pellet stoves is expected to adversely impact air quality. The atmospheric aging of pellet emissions has received even less attention, focusing mainly on daytime conditions, while the degree to which pellet emissions undergo night-time aging as well as the role of relative humidity remain poorly understood.
View Article and Find Full Text PDFComputer-generated atomistic microstructures of atmospheric nanoparticles are geometrically analyzed using Delaunay tessellation followed by Monte Carlo integration to compute their free and accessible volume. The nanoparticles studied consist of -pinonic acid (a biogenic organic aerosol component), inorganic ions (sulfate and ammonium), and water. Results are presented for the free or unoccupied volume in different domains of the nanoparticles and its dependence on relative humidity and organic content.
View Article and Find Full Text PDFWhile the number and types of indoor air pollutants is rising, much is suspected but little is known about the impact of their potentially synergistic interactions, upon human health. Gases, particulate matter, organic compounds but also allergens and viruses, fall within the 'pollutant' definition. Distinct populations, such as children and allergy and asthma sufferers are highly susceptible, while a low socioeconomic background is a further susceptibility factor; however, no specific guidance is available.
View Article and Find Full Text PDFParticulate matter from biomass burning emissions affects air quality, ecosystems and climate; however, quantifying these effects requires that the connection between primary emissions and secondary aerosol production is firmly established. We performed atmospheric simulation chamber experiments on the chemical oxidation of residential biomass burning emissions under dark conditions. Biomass burning organic aerosol was found to age under dark conditions, with its oxygen-to-carbon ratio increasing by 7-34% and producing 1-38 μg m of secondary organic aerosol (5-80% increase over the fresh organic aerosol) after 30 min of exposure to NO radicals in the chamber (corresponding to 1-3 h of exposure to typical nighttime NO radical concentrations in an urban environment).
View Article and Find Full Text PDFEach year, millions of premature deaths worldwide are caused by exposure to outdoor air pollution, especially fine particulate matter (PM2.5). Designing policies to reduce these deaths relies on air quality modeling for estimating changes in PM2.
View Article and Find Full Text PDFA method for the measurement of the water solubility distribution of atmospheric organic aerosols is presented. This method is based on the extraction of organic aerosols collected on filters, using different amounts of water and measurement of the corresponding water-soluble organic carbon concentration. The solubility distribution is then estimated using the solubility basis set.
View Article and Find Full Text PDFThe purpose of this study was to estimate cardiopulmonary mortality associations for long-term exposure to PM species and sources (i.e., components) within the U.
View Article and Find Full Text PDFBecause of the direct interaction of lungs with the environment, respiratory diseases are among the leading causes of environment-related deaths in the world. Chronic obstructive pulmonary disease (COPD) and cystic fibrosis (CF) are two highly debilitating diseases that are of particular interest in the context of environmental studies; they both are characterized by a similar progressive loss of lung function with small bronchi alterations, and a high phenotypic variability of unknown origin, which prevents a good therapeutic efficacy. In the last years, there has been an evolution in the apprehension of the study of diseases going from a restricted "one exposure, one disease" approach to a broader concept with other associating factors, the exposome.
View Article and Find Full Text PDFAcidity profoundly affects almost every aspect that shapes the composition of ambient particles and their environmental impact. Thermodynamic analysis of gas-particle composition datasets offers robust estimates of acidity, but they are not available for long periods of time. Fog composition datasets, however, are available for many decades; we develop a thermodynamic analysis to estimate the ammonia in equilibrium with fog water and to infer the pre-fog aerosol pH starting from fog chemical composition and pH.
View Article and Find Full Text PDFProc Natl Acad Sci U S A
May 2021
Agriculture is a major contributor to air pollution, the largest environmental risk factor for mortality in the United States and worldwide. It is largely unknown, however, how individual foods or entire diets affect human health via poor air quality. We show how food production negatively impacts human health by increasing atmospheric fine particulate matter (PM), and we identify ways to reduce these negative impacts of agriculture.
View Article and Find Full Text PDFOxidized organic aerosol (OOA) is a major component of ambient particulate matter, substantially impacting climate, human health, and ecosystems. OOA is readily produced in the presence of sunlight, and requires days of photooxidation to reach the levels observed in the atmosphere. High concentrations of OOA are thus expected in the summer; however, our current mechanistic understanding fails to explain elevated OOA during wintertime periods of low photochemical activity that coincide with periods of intense biomass burning.
View Article and Find Full Text PDFThis study investigates the major chemical components, particle-bound water content, acidity (pH), and major potential sources of PM in major cities (Belluno, Conegliano, Vicenza, Mestre, Padua, and Rovigo) in the eastern end of the Po Valley. The measured PM mass was reconstructed using a multiple-site hybrid chemical mass closure approach that also accounts for aerosol inorganic water content (AWC) estimated by the ISORROPIA-II model. Annually, organic matter accounted for 31-45% of the PM at all sites, followed by nitrate (10-19%), crustal material (10-14%), sulfate (8-10%), ammonium (5-9%), elemental carbon (4-7%), other inorganic ions (3-4%), and trace elements (0.
View Article and Find Full Text PDFA dual smog chamber system was used to quantify the formation rates of secondary organic and inorganic aerosol in an urban environment (Pittsburgh, US). Ambient air was introduced in both chambers, and HONO photolysis was used to produce hydroxyl radicals (OH) in the perturbed chamber. The second chamber was used as a reference.
View Article and Find Full Text PDFThe properties and the chemical fate of later generation products of the oxidation of biogenic organic compounds are mostly unknown. The properties of fresh MBTCA aerosol, a later generation product of the oxidation of monoterpenes in the atmosphere, were determined combining an aerosol mass spectrometer (AMS), a thermodenuder, and a scanning mobility particle sizer. Based on its AMS spectrum m/z 141.
View Article and Find Full Text PDFAlthough they are currently unregulated, atmospheric ultrafine particles (<100 nm) pose health risks because of, e.g., their capability to penetrate deep into the respiratory system.
View Article and Find Full Text PDFMolecular dynamics (MD) simulations were employed to investigate the local structure and local concentration in atmospheric nanoparticles consisting of an organic compound (cis-pinonic acid or n-CH), sulfate and ammonium ions, and water. Simulations in the isothermal-isobaric (NPT) statistical ensemble under atmospheric conditions with a prespecified number of molecules of the abovementioned compounds led to the formation of a nanoparticle. Calculations of the density profiles of all the chemical species in the nanoparticle, the corresponding radial pair distribution functions, and their mobility inside the nanoparticle revealed strong interactions developing between sulfate and ammonium ions.
View Article and Find Full Text PDFSecondary organic aerosols (SOA) are a large source of uncertainty in our current understanding of climate change and air pollution. The phase state of SOA is important for quantifying their effects on climate and air quality, but its global distribution is poorly characterized. We developed a method to estimate glass transition temperatures based on the molar mass and molecular O:C ratio of SOA components, and we used the global chemistry climate model EMAC with the organic aerosol module ORACLE to predict the phase state of atmospheric SOA.
View Article and Find Full Text PDFFive case studies (Athens and Paris in Europe, Pittsburgh and Los Angeles in the United States, and Mexico City in Central America) are used to gain insights into the changing levels, sources, and role of atmospheric chemical processes in air quality in large urban areas as they develop technologically. Fine particulate matter is the focus of our analysis. In all cases reductions of emissions by industrial and transportation sources have resulted in significant improvements in air quality during the last few decades.
View Article and Find Full Text PDFThe effect of ammonia on the partitioning of two dicarboxylic acids, oxalic (C2) and adipic (C6) is determined. Measurements by a tandem differential mobility analysis system and a thermodenuder (TD-TDMA) system are used to estimate the saturation vapor pressure and enthalpy of vaporization of ammonium oxalate and adipate. Ammonia dramatically lowered the vapor pressure of oxalic acid, by several orders of magnitude, with an estimated vapor pressure of 1.
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