A5084092408- Atmospheric chemistry and aerosols
- Atmospheric Ozone and Climate
- Air Quality and Health Impacts
- Atmospheric and Environmental Gas Dynamics
- Air Quality Monitoring and Forecasting
- Spectroscopy and Laser Applications
- Atmospheric aerosols and clouds
- Vehicle emissions and performance
- Fire effects on ecosystems
- Water Quality Monitoring and Analysis
- Catalytic Processes in Materials Science
- Advanced Chemical Sensor Technologies
- Toxic Organic Pollutants Impact
- Marine Biology and Ecology Research
- Advanced Chemical Physics Studies
- COVID-19 impact on air quality
- Marine Bivalve and Aquaculture Studies
- Fire dynamics and safety research
- Marine and coastal ecosystems
- Heavy metals in environment
- Thermochemical Biomass Conversion Processes
- Mass Spectrometry Techniques and Applications
- Isotope Analysis in Ecology
- Environmental Toxicology and Ecotoxicology
- Odor and Emission Control Technologies
National Oceanic and Atmospheric Administration
2016-2025
NOAA Chemical Sciences Laboratory
2010-2025
NOAA Earth System Research Laboratory
2014-2025
University of Colorado Boulder
2016-2025
University of Colorado System
2011-2025
Cooperative Institute for Research in Environmental Sciences
2004-2024
University of Nevada, Reno
2024
Laboratory for Atmospheric and Space Physics
2024
Goddard Space Flight Center
2024
Dow Chemical (United States)
2010-2021
Oxidation of biogenic volatile organic compounds (BVOC) by the nitrate radical (NO3) represents one important interactions between anthropogenic emissions related to combustion and natural from biosphere. This interaction has been recognized for more than 3 decades, during which time a large body research emerged laboratory, field, modeling studies. NO3-BVOC reactions influence air quality, climate visibility through regional global budgets reactive nitrogen (particularly nitrates), ozone,...
Nitrogen oxides in the lower troposphere catalyze photochemical production of ozone (O3) pollution during day but react to form nitric acid, oxidize hydrocarbons, and remove O3 at night. A key nocturnal reaction is heterogeneous hydrolysis dinitrogen pentoxide, N2O5. We report aircraft measurements NO3 N2O5, which show that N2O5 uptake coefficient, g(N2O5), on aerosol particles highly variable depends strongly composition, particularly sulfate content. The results have implications for...
Speciated particle-phase organic nitrates (pONs) were quantified using online chemical ionization MS during June and July of 2013 in rural Alabama as part the Southern Oxidant Aerosol Study. A large fraction pONs is highly functionalized, possessing between six eight oxygen atoms within each carbon number group, not common first generation alkyl previously reported. Using calibrations for isoprene hydroxynitrates measured molecular compositions, we estimate that account 3% 8% total...
Abstract. Volatile and intermediate-volatility non-methane organic gases (NMOGs) released from biomass burning were measured during laboratory-simulated wildfires by proton-transfer-reaction time-of-flight mass spectrometry (PTR-ToF). We identified NMOG contributors to more than 150 PTR ion masses using gas chromatography (GC) pre-separation with electron ionization, H3O+ chemical NO+ an extensive literature review, time series correlation, providing higher certainty for identifications has...
Abstract. The yields of organic nitrates and secondary aerosol (SOA) particle formation were measured for the reaction NO3+β-pinene under dry humid conditions in atmosphere simulation chamber SAPHIR at Research Center Jülich. These experiments conducted low concentrations NO3 (NO3+N2O5<10 ppb) β-pinene (peak~15 ppb), with no seed aerosol. SOA was observed to be prompt substantial (~50% mass yield both 60% RH), highly correlated nitrate formation. gas/aerosol partitioning can simulated...
Dimethyl sulfide (DMS), emitted from the oceans, is most abundant biological source of sulfur to marine atmosphere. Atmospheric DMS oxidized condensable products that form secondary aerosols affect Earth's radiative balance by scattering solar radiation and serving as cloud condensation nuclei. We report atmospheric discovery a previously unquantified oxidation product, hydroperoxymethyl thioformate (HPMTF, HOOCH2SCHO), identified through global-scale airborne observations demonstrate it be...
Particle pH is a critical but poorly constrained quantity that affects many aerosol processes and properties, including composition, concentrations, toxicity. We assess PM1 as function of geographical location altitude, focusing on the northeastern U.S., based aircraft measurements from Wintertime Investigation Transport, Emissions, Reactivity campaign (1 February to 15 March 2015). water were predicted with ISORROPIA-II thermodynamic model validated by comparing observed partitioning...
Abstract Brown carbon aerosol consists of light‐absorbing organic particulate matter with wavelength‐dependent absorption. Aerosol optical extinction, absorption, size distributions, and chemical composition were measured in rural Alabama during summer 2013. The field site was well located to examine sources brown aerosol, influence by high biogenic concentrations, pollution from two nearby cities, biomass burning aerosol. We report the closure between dry extinction at 365 nm calculated...
Significance Recent work in Los Angeles has shown that urban volatile organic compound (VOC) emissions from consumer and industrial products—termed chemical products (VCPs)—are now an important source of ozone precursors. Using advancements VOC instrumentation, we show VCP are ubiquitous regions can be identified via unique fingerprints. Through detailed modeling, VCPs as to production fossil fuel VOCs the chemistry have significant impacts on model simulations key atmospheric processes....
The secondary organic aerosol (SOA) mass yields from NO3 oxidation of a series biogenic volatile compounds (BVOCs), consisting five monoterpenes and one sesquiterpene (α-pinene, β-pinene, Δ-3-carene, limonene, sabinene, β-caryophyllene), were investigated in continuous flow experiments 10 m3 indoor Teflon chamber. By making situ measurements the nitrate radical employing kinetics box model, we generate time-dependent yield curves as function reacted BVOC. SOA varied dramatically among...
Although laboratory experiments have shown that organic compounds in both gasoline fuel and diesel engine exhaust can form secondary aerosol (SOA), the fractional contribution from emissions to ambient SOA urban environments is poorly known. Here we use airborne ground‐based measurements of (OA) Los Angeles (LA) Basin, California made during May June 2010 assess amount formed emissions. Diesel LA Basin vary between weekdays weekends, with 54% lower on weekends. Despite this difference source...
The magnitude and sources of chlorine atoms in marine air remain highly uncertain but have potentially important consequences for quality polluted coastal regions. We made continuous measurements ambient ClNO(2) Cl(2) concentrations from May 15 to June 8 aboard the Research Vessel Atlantis during CalNex 2010 field study. In Los Angeles region, was more ubiquitous than most nights study period. ranged detection limits at midday campaign maximum values night reaching 2100 200 pptv,...
Abstract. At the Rocky Mountain Biogenic Aerosol Study (BEACHON-RoMBAS) field campaign in Colorado front range, July–August 2011, measurements of gas- and aerosol-phase organic nitrates enabled a study role NOx (NOx = NO + NO2) oxidation forest-emitted volatile compounds (VOCs) subsequent aerosol formation. Substantial formation peroxy- alkyl-nitrates is observed every morning, with an apparent 2.9% yield alkyl from daytime RO2 reactions. Aerosol-phase nitrates, however, peak concentration...
The coronavirus-19 (COVID-19) pandemic led to government interventions limit the spread of disease which are unprecedented in recent history; for example, stay at home orders sudden decreases atmospheric emissions from transportation sector. In this review article, current understanding influence emission reductions on pollutant concentrations and air quality is summarized nitrogen dioxide (NO2), particulate matter (PM2.5), ozone (O3), ammonia, sulfur dioxide, black carbon, volatile organic...
We use a large laboratory, modeling, and field dataset to investigate the isoprene + O<sub>3</sub> reaction, with goal of better understanding fates C<sub>1</sub> C<sub>4</sub> Criegee intermediates in atmosphere.
Significance Exposure to fine particulate matter is a leading cause of premature deaths and illnesses globally. In the eastern United States, substantial cuts in sulfur dioxide nitrogen oxides emissions have considerably lowered sulfate nitrate concentrations for all seasons except winter. Simulations that reproduce detailed airborne observations wintertime atmospheric chemistry over States indicate formation limited by availability oxidants acidity particles, respectively. These limitations...
<p><strong>Abstract.</strong> Gas- and aerosol-phase measurements of oxidants, biogenic volatile organic compounds (BVOCs) nitrates made during the Southern Oxidant Aerosol Study (SOAS campaign, Summer 2013) in central Alabama show that a nitrate radical (NO<sub>3</sub>) reaction with monoterpenes leads to significant secondary aerosol formation. Cumulative losses NO<sub>3</sub> terpenes are correlated increase gas- aerosol-organic concentrations...
Abstract Nitryl chloride (ClNO 2 ) plays potentially important roles in atmospheric chemistry, but its abundance and effect are not fully understood due to the small number of ambient observations ClNO date. In late autumn 2013, was measured with a chemical ionization mass spectrometer (CIMS) at mountain top (957 m above sea level) Hong Kong. During 12 nights continuous CIMS data, elevated mixing ratios (>400 parts per trillion by volume) or precursor N O 5 (>1000 pptv) were observed...
Abstract Nocturnal dinitrogen pentoxide (N 2 O 5 ) heterogeneous chemistry impacts regional air quality and the distribution lifetime of tropospheric oxidants. Formed from oxidation nitrogen oxides, N is heterogeneously lost to aerosol with a highly variable reaction probability, γ ), dependent on composition ambient conditions. Reaction products include soluble nitrate (HNO 3 or NO − nitryl chloride (ClNO ). We report first‐ever derivations wintertime aircraft measurements in critically...