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  1. Article ; Online: A sulfuric acid nucleation potential model for the atmosphere

    J. S. Johnson / C. N. Jen

    Atmospheric Chemistry and Physics, Vol 22, Pp 8287-

    2022  Volume 8297

    Abstract: Observations over the last decade have demonstrated that the atmosphere contains potentially hundreds of compounds that can react with sulfuric acid to nucleate stable aerosol particles. Consequently, modeling atmospheric nucleation requires detailed ... ...

    Abstract Observations over the last decade have demonstrated that the atmosphere contains potentially hundreds of compounds that can react with sulfuric acid to nucleate stable aerosol particles. Consequently, modeling atmospheric nucleation requires detailed knowledge of nucleation reaction kinetics and spatially and temporally resolved measurements of numerous precursor compounds. This study introduces the Nucleation Potential Model (NPM), a novel nucleation model that dramatically simplifies the diverse reactions between sulfuric acid and any combination of precursor gases. The NPM predicts 1 nm nucleation rates from only two measurable gas concentrations, regardless of whether all precursor gases are known. The NPM describes sulfuric acid nucleating with a parameterized base compound at an effective base concentration, [ B eff ]. [ B eff ] captures the ability of a compound or mixture to form stable clusters with sulfuric acid and is estimated from measured 1 nm particle concentrations. The NPM is applied to experimental and field observations of sulfuric acid nucleation to demonstrate how [ B eff ] varies for different stabilizing compounds, mixtures, and sampling locations. Analysis of previous field observations shows distinct differences in [ B eff ] between locations that follow the emission sources and stabilizing compound concentrations for that region. Overall, the NPM allows researchers to easily model nucleation across diverse environments and estimate the concentration of non-sulfuric acid precursors using a condensation particle counter.
    Keywords Physics ; QC1-999 ; Chemistry ; QD1-999
    Subject code 669
    Language English
    Publishing date 2022-06-01T00:00:00Z
    Publisher Copernicus Publications
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  2. Article ; Online: Chemical composition of PM 2.5 in October 2017 Northern California wildfire plumes

    Y. Liang / C. N. Jen / R. J. Weber / P. K. Misztal / A. H. Goldstein

    Atmospheric Chemistry and Physics, Vol 21, Pp 5719-

    2021  Volume 5737

    Abstract: Wildfires have become more common and intense in the western US over recent decades due to a combination of historical land management practices and warming climate. Emissions from large-scale fires now frequently affect populated regions such as the San ...

    Abstract Wildfires have become more common and intense in the western US over recent decades due to a combination of historical land management practices and warming climate. Emissions from large-scale fires now frequently affect populated regions such as the San Francisco Bay Area during the fall wildfire season, with documented impacts of the resulting particulate matter on human health. Health impacts of exposure to wildfire emissions depend on the chemical composition of particulate matter, but the molecular composition of the real biomass burning organic aerosol (BBOA) that reaches large population centers remains insufficiently characterized. We took PM 2.5 (particles having aerodynamic diameters less than or equal to 2.5 µm ) samples at the University of California, Berkeley campus ( ∼ 60 km downwind of the fires) during the October 2017 Northern California wildfires period and analyzed molecular composition of OA using a two-dimensional gas chromatography coupled with high-resolution time-of-flight mass spectrometry (GC × GC HR-ToF-MS). Sugar-like compounds were the most abundant component of BBOA, followed by mono-carboxylic acids, aromatic compounds, other oxygenated compounds, and terpenoids. The vast majority of compounds detected in smoke have unknown health impacts. Regression models were trained to predict the saturation vapor pressure and averaged carbon oxidation state ( <math xmlns="http://www.w3.org/1998/Math/MathML" id="M7" display="inline" overflow="scroll" dspmath="mathml"><mover accent="true"><mrow><msub><mi mathvariant="normal">OS</mi><mi mathvariant="normal">c</mi></msub></mrow><mo mathvariant="normal">‾</mo></mover></math> <svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="23pt" height="16pt" class="svg-formula" dspmath="mathimg" md5hash="2ed822bb6f358924dcfc775b7e6ab894"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="acp-21-5719-2021-ie00001.svg" width="23pt" height="16pt" src="acp-21-5719-2021-ie00001.png"/></svg:svg> ) of detected compounds. The compounds speciated have a wide volatility distribution and most of them are highly oxygenated. In addition, time series of primary BBOA tracers observed in Berkeley were found to be indicative of the types of plants in the ecosystems burned in Napa and Sonoma, and could be used to differentiate the regions from which the smoke must have originated. Commonly used secondary BBOA markers like 4-nitrocatechol were enhanced when plumes aged, but their very fast formation caused them to have similar temporal variation as primary BBOA tracers. Using hierarchical clustering analysis, we classified compounds into seven factors indicative of their sources and transformation processes, identifying a unique daytime secondary BBOA factor. Chemicals associated with this factor include multifunctional acids and oxygenated aromatic compounds. These compounds have high <math xmlns="http://www.w3.org/1998/Math/MathML" id="M8" display="inline" overflow="scroll" dspmath="mathml"><mover accent="true"><mrow><msub><mi mathvariant="normal">OS</mi><mi mathvariant="normal">c</mi></msub></mrow><mo mathvariant="normal">‾</mo></mover></math> <svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="23pt" height="16pt" class="svg-formula" dspmath="mathimg" md5hash="4dc6696907890d1e0d046bd6b7b98d55"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="acp-21-5719-2021-ie00002.svg" width="23pt" height="16pt" src="acp-21-5719-2021-ie00002.png"/></svg:svg> , and they are also semi-volatile. We observed no net particle-phase organic carbon formation, which indicates an approximate balance between the mass of evaporated organic carbonaceous compounds and the addition of secondary organic carbonaceous compounds.
    Keywords Physics ; QC1-999 ; Chemistry ; QD1-999
    Subject code 550
    Language English
    Publishing date 2021-04-01T00:00:00Z
    Publisher Copernicus Publications
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  3. Article ; Online: Chemical ionization of clusters formed from sulfuric acid and dimethylamine or diamines

    C. N. Jen / J. Zhao / P. H. McMurry / D. R. Hanson

    Atmospheric Chemistry and Physics, Vol 16, Pp 12513-

    2016  Volume 12529

    Abstract: Chemical ionization (CI) mass spectrometers are used to study atmospheric nucleation by detecting clusters produced by reactions of sulfuric acid and various basic gases. These instruments typically use nitrate to deprotonate and thus chemically ionize ... ...

    Abstract Chemical ionization (CI) mass spectrometers are used to study atmospheric nucleation by detecting clusters produced by reactions of sulfuric acid and various basic gases. These instruments typically use nitrate to deprotonate and thus chemically ionize the clusters. In this study, we compare cluster concentrations measured using either nitrate or acetate. Clusters were formed in a flow reactor from vapors of sulfuric acid and dimethylamine, ethylene diamine, tetramethylethylene diamine, or butanediamine (also known as putrescine). These comparisons show that nitrate is unable to chemically ionize clusters with high base content. In addition, we vary the ion–molecule reaction time to probe ion processes which include proton-transfer, ion–molecule clustering, and decomposition of ions. Ion decomposition upon deprotonation by acetate/nitrate was observed. More studies are needed to quantify to what extent ion decomposition affects observed cluster content and concentrations, especially those chemically ionized with acetate since it deprotonates more types of clusters than nitrate. Model calculations of the neutral and ion cluster formation pathways are also presented to better identify the cluster types that are not efficiently deprotonated by nitrate. Comparison of model and measured clusters indicate that sulfuric acid dimers with two diamines and sulfuric acid trimers with two or more base molecules are not efficiently chemical ionized by nitrate. We conclude that acetate CI provides better information on cluster abundancies and their base content than nitrate CI.
    Keywords Physics ; QC1-999 ; Chemistry ; QD1-999
    Subject code 540
    Language English
    Publishing date 2016-10-01T00:00:00Z
    Publisher Copernicus Publications
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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    Inter-library loan at ZB MED

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  4. Article ; Online: Speciated and total emission factors of particulate organics from burning western US wildland fuels and their dependence on combustion efficiency

    C. N. Jen / L. E. Hatch / V. Selimovic / R. J. Yokelson / R. Weber / A. E. Fernandez / N. M. Kreisberg / K. C. Barsanti / A. H. Goldstein

    Atmospheric Chemistry and Physics, Vol 19, Pp 1013-

    2019  Volume 1026

    Abstract: Western US wildlands experience frequent and large-scale wildfires which are predicted to increase in the future. As a result, wildfire smoke emissions are expected to play an increasing role in atmospheric chemistry while negatively impacting regional ... ...

    Abstract Western US wildlands experience frequent and large-scale wildfires which are predicted to increase in the future. As a result, wildfire smoke emissions are expected to play an increasing role in atmospheric chemistry while negatively impacting regional air quality and human health. Understanding the impacts of smoke on the environment is informed by identifying and quantifying the chemical compounds that are emitted during wildfires and by providing empirical relationships that describe how the amount and composition of the emissions change based upon different fire conditions and fuels. This study examined particulate organic compounds emitted from burning common western US wildland fuels at the US Forest Service Fire Science Laboratory. Thousands of intermediate and semi-volatile organic compounds (I/SVOCs) were separated and quantified into fire-integrated emission factors (EFs) using a thermal desorption, two-dimensional gas chromatograph with online derivatization coupled to an electron ionization/vacuum ultraviolet high-resolution time-of-flight mass spectrometer (TD-GC × GC-EI/VUV-HRToFMS). Mass spectra, EFs as a function of modified combustion efficiency (MCE), fuel source, and other defining characteristics for the separated compounds are provided in the accompanying mass spectral library. Results show that EFs for total organic carbon (OC), chemical families of I/SVOCs, and most individual I/SVOCs span 2–5 orders of magnitude, with higher EFs at smoldering conditions (low MCE) than flaming. Logarithmic fits applied to the observations showed that log (EFs) for particulate organic compounds were inversely proportional to MCE. These measurements and relationships provide useful estimates of EFs for OC, elemental carbon (EC), organic chemical families, and individual I/SVOCs as a function of fire conditions.
    Keywords Physics ; QC1-999 ; Chemistry ; QD1-999
    Subject code 540
    Language English
    Publishing date 2019-01-01T00:00:00Z
    Publisher Copernicus Publications
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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    Inter-library loan at ZB MED

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  5. Article ; Online: Evolution of the chemical fingerprint of biomass burning organic aerosol during aging

    A. Bertrand / G. Stefenelli / C. N. Jen / S. M. Pieber / E. A. Bruns / H. Ni / B. Temime-Roussel / J. G. Slowik / A. H. Goldstein / I. El Haddad / U. Baltensperger / A. S. H. Prévôt / H. Wortham / N. Marchand

    Atmospheric Chemistry and Physics, Vol 18, Pp 7607-

    2018  Volume 7624

    Abstract: A thermal desorption aerosol gas chromatograph coupled to a high resolution – time of flight – aerosol mass spectrometer (TAG-AMS) was connected to an atmospheric chamber for the molecular characterization of the evolution of organic aerosol (OA) emitted ...

    Abstract A thermal desorption aerosol gas chromatograph coupled to a high resolution – time of flight – aerosol mass spectrometer (TAG-AMS) was connected to an atmospheric chamber for the molecular characterization of the evolution of organic aerosol (OA) emitted by woodstove appliances for residential heating. Two log woodstoves (old and modern) and one pellet stove were operated under typical conditions. Emissions were aged during a time equivalent to 5 h of atmospheric aging. The five to seven samples were collected and analyzed with the TAG-AMS during each experiment. We detected and quantified over 70 compounds, including levoglucosan and nitrocatechols. We calculate the emission factor (EF) of these tracers in the primary emissions and highlight the influence of the combustion efficiency on these emissions. Smoldering combustion contributes to a higher EF and a more complex composition. We also demonstrate the effect of atmospheric aging on the chemical fingerprint. The tracers are sorted into three categories according to the evolution of their concentration: primary compounds, non-conventional primary compounds, and secondary compounds. For each, we provide a quantitative overview of their contribution to the OA mass at different times of the photo-oxidative process.
    Keywords Physics ; QC1-999 ; Chemistry ; QD1-999
    Subject code 550
    Language English
    Publishing date 2018-06-01T00:00:00Z
    Publisher Copernicus Publications
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  6. Article ; Online: Light-absorbing secondary organic material formed by glyoxal in aqueous aerosol mimics

    E. L. Shapiro / J. Szprengiel / N. Sareen / C. N. Jen / M. R. Giordano / V. F. McNeill

    Atmospheric Chemistry and Physics, Vol 9, Iss 7, Pp 2289-

    2009  Volume 2300

    Abstract: Light-absorbing and high-molecular-weight secondary organic products were observed to result from the reaction of glyoxal in mildly acidic (pH=4) aqueous inorganic salt solutions mimicking aqueous tropospheric aerosol particles. High-molecular-weight ( ... ...

    Abstract Light-absorbing and high-molecular-weight secondary organic products were observed to result from the reaction of glyoxal in mildly acidic (pH=4) aqueous inorganic salt solutions mimicking aqueous tropospheric aerosol particles. High-molecular-weight (500–600 amu) products were observed when ammonium sulfate ((NH 4 ) 2 SO 4 ) or sodium chloride (NaCl) was present in the aqueous phase. The products formed in (NH 4 ) 2 SO 4 or ammonium nitrate (NH 4 NO 3 ) solutions absorb light at UV and visible wavelengths. Substantial absorption at 300–400 nm develops within two hours, and absorption between 400–600 nm develops within days. Pendant drop tensiometry measurements show that the products are not surface-active. The experimental results along with ab initio predictions of the UV/Vis absorption of potential products suggest a mechanism involving the participation of the ammonium ion. If similar products are formed in atmospheric aerosol particles, they could change the optical properties of the seed aerosol over its lifetime.
    Keywords Environmental sciences ; GE1-350 ; Geography. Anthropology. Recreation ; G ; DOAJ:Environmental Sciences ; DOAJ:Earth and Environmental Sciences
    Subject code 535
    Publishing date 2009-04-01T00:00:00Z
    Publisher Copernicus GmbH
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  7. Article ; Online: Light-absorbing secondary organic material formed by glyoxal in aqueous aerosol mimics

    E. L. Shapiro / J. Szprengiel / N. Sareen / C. N. Jen / M. R. Giordano / V. F. McNeill

    Atmospheric Chemistry and Physics Discussions, Vol 9, Iss 1, Pp 59-

    2009  Volume 80

    Abstract: Light-absorbing and high-molecular-weight secondary organic products were observed to result from the reaction of glyoxal in mildly acidic (pH=4) aqueous inorganic salt solutions mimicking aqueous tropospheric aerosol particles. High-molecular-weight ( ... ...

    Abstract Light-absorbing and high-molecular-weight secondary organic products were observed to result from the reaction of glyoxal in mildly acidic (pH=4) aqueous inorganic salt solutions mimicking aqueous tropospheric aerosol particles. High-molecular-weight (500–600 amu) products were observed when ammonium sulfate ((NH 4 ) 2 SO 4 ) or sodium chloride (NaCl) was present in the aqueous phase. The products formed in the (NH 4 ) 2 SO 4 solutions absorb light at UV and visible wavelengths. Substantial absorption at 300–400 nm develops within two hours, and absorption between 400–600 nm develops within days. Pendant drop tensiometry measurements show that the products are not surface-active. The experimental results along with ab initio predictions of the UV/Vis absorption of potential products suggest that an aldol condensation mechanism is active in the glyoxal-(NH 4 ) 2 SO 4 system, resulting in the formation of pi-conjugated products. If similar products are formed in atmospheric aerosol particles, they could change the optical properties of the seed aerosol over its lifetime.
    Keywords Environmental sciences ; GE1-350 ; Geography. Anthropology. Recreation ; G ; DOAJ:Environmental Sciences ; DOAJ:Earth and Environmental Sciences ; Geophysics. Cosmic physics ; QC801-809
    Subject code 290 ; 535
    Language English
    Publishing date 2009-01-01T00:00:00Z
    Publisher Copernicus Publications
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

    Full text online

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    Inter-library loan at ZB MED

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