A5022493174- Atmospheric chemistry and aerosols
- Air Quality and Health Impacts
- Atmospheric Ozone and Climate
- Catalytic Processes in Materials Science
- Air Quality Monitoring and Forecasting
- Vehicle emissions and performance
- Atmospheric aerosols and clouds
- Fire effects on ecosystems
- Indoor Air Quality and Microbial Exposure
- Fluid Dynamics and Thin Films
- Toxic Organic Pollutants Impact
- Fire dynamics and safety research
- Industrial Gas Emission Control
- Water Quality Monitoring and Analysis
- Icing and De-icing Technologies
- Heavy metals in environment
- Adhesion, Friction, and Surface Interactions
- Thermochemical Biomass Conversion Processes
- Pharmacogenetics and Drug Metabolism
- Catalysis and Oxidation Reactions
- Mercury impact and mitigation studies
- Groundwater and Isotope Geochemistry
- Atmospheric and Environmental Gas Dynamics
- Water Governance and Infrastructure
- Plant Physiology and Cultivation Studies
Japan Tobacco (Japan)
2023
Clarkson University
2016-2020
Kochi Prefectural Education Center
2019
University of California, Riverside
2009-2016
Colorado State University
2012-2016
Tottori University
2013-2014
Federal Emergency Management Agency
2011
Keio University
2007-2009
Abstract Total suspended particulate (TSP) and matter less than 2.5 μm in aerodynamic diameter (PM2.5) sam ples were collected over Xi'an for a 1-yr period to characterize the seasonal variations of water-soluble inorganic ions evaluate effectiveness pollution policies controls during past 10 yr. Mass concentrations five cations (sodium [Na+], potassium [K+], ammonium [NH4 +]], calcium [Ca2+], magnesium [Mg2+) four anions (fluoride [F−], chloride [Cl−], nitrate [NO3 −], sulfate [SO4 2−])...
Real time secondary organic aerosol (SOA) density evolution for m-xylene photo-oxidation and α-pinene ozonolysis was obtained using an Aerosol Particle Mass Analyzer (APM)/Scanning Mobility Spectrometer (SMPS) setup, which has been modified to achieve higher transmission of particles improved sampling frequency. The SOA generated from found be 1.24 ± 0.03 g/cm3 while the determined 1.35 g/cm3. These results confirm measurement approach a combined SMPS Aerodyne (AMS) system are within good...
Abstract An improved understanding of atmospheric ice nucleating particles (INP), including sources and abundance, is needed to advance our aerosol‐cloud‐climate interactions. This study examines diverse biomass burning events better constrain how fires impact populations INP. Sampling prescribed burns wildfires in Colorado Georgia, U.S.A., revealed that leads the release are active as condensation/immersion freezing INP at temperatures from −32 −12°C. During wiregrass, up 64% collected...
The burning of biomasses releases fluorine to the atmosphere, representing a major and previously uncharacterized flux this atmospheric pollutant. Emissions fine particle (PM2.5) water-soluble fluoride (F-) from biomass were evaluated during fourth Fire Laboratory at Missoula Experiment (FLAME-IV) using scanning electron microscopy energy dispersive X-ray spectroscopy (SEM-EDX) ion chromatography with conductivity detection. F- was detected in 100% PM2.5 emissions conifers (n=11), 94%...
Abstract. SOA formation from benzene, toluene, m-xylene, and their corresponding phenolic compounds were investigated using the UCR/CE-CERT Environmental Chamber to evaluate importance of as intermediate species in aromatic formation. yield measurements coupled gas-phase indicate that approximately 20% m-xylene could be ascribed route under low NOx conditions. The densities tend initially high 1.8 g cm−3 eventually reach range 1.3–1.4 cm−3. final density was found independent elemental ratio...
Isoprene is globally the most ubiquitous nonmethane hydrocarbon. The biogenic emission found in abundance and has a propensity for SOA formation diverse climates. It important to characterize isoprene with varying reaction temperature. In this work, effect of temperature on formation, physical properties, chemical nature probed. Three experimental systems are probed effects from isoprene, NO + H2O2 photo-oxidation, only dark ozonolysis. These experiments show that readily forms unseeded...
Abstract Ice‐nucleating particles (INPs) are required for initial ice crystal formation in clouds at temperatures warmer than about −36°C and thus play a crucial role cloud precipitation formation. Biomass burning has been found to be source of INPs previous studies is also major contributor atmospheric black carbon (BC) concentrations. This study focuses on isolating the BC contribution INP population associated with biomass combustion. Emissions condensation mode from number globally...
Abstract. The molecular structure of volatile organic compounds determines their oxidation pathway, directly impacting secondary aerosol (SOA) formation. This study comprehensively investigates the impact on SOA formation from photooxidation 12 different eight- to nine-carbon aromatic hydrocarbons under low-NOx conditions. effects alkyl substitute number, location, carbon chain length and branching are demonstrated by analyzing yield, chemical composition physical properties. Aromatic...
Secondary organic aerosol (SOA) formation from diesel exhaust was investigated using an environmental chamber. Particle volume measurement based solely on mobility diameter underestimated the SOA due to external void space of agglomerate particles. Therefore, particle mass concentration and fractal-like dimension determined effective density as a function analyzer scanning sizer (APM–SMPS). Continuous aging measured by increase atomic ratio (O/C) underscored importance multigenerational...
Abstract. Substitution of methyl groups onto the aromatic ring determines secondary organic aerosol (SOA) formation from monocyclic hydrocarbon precursor (SOA yield and chemical composition). This study links number on to SOA hydrocarbons photooxidation under low-NOx conditions (HC/NO > 10 ppbC : ppb). Monocyclic with increasing numbers are systematically studied. pentamethylbenzene hexamethylbenzene reported for first time. A decreasing is observed. Linear trends found in both f44 vs....
Abstract Combining field and laboratory results, we present biomass smoke physical properties. We report sub‐0.56 µm diameter ( D p ) particle sizing (fast mobility sizer, FMPS) plus light absorption scattering at 870 nm (photoacoustic extinctiometer). For < 200 nm, the FMPS characterized within ±20% compared to standards. As traditional scanning responded most accurately single‐mode polydispersions with mean which sampled here. Smoke was measured from fresh emissions (seconds hours old),...
Correlations between O/C and cloud condensation nucleus activity, represented by κ, are a computationally efficient approach to estimate the impact of aerosol aging on formation climate; however, previously reported correlations these two variables empirical vary widely in their slopes extrapolations high values. This study proposes theoretical framework that bridges elemental ratios, volatility, solubility, κ. The estimates intrinsic κ based molecular formulas organics composed carbon,...
In 1998, the U.S. Environmental Protection Agency (EPA) initiated a major air quality program known as Particulate Matter (PM) Supersites Program. The Program was multiyear, $27 million monitoring consisting of eight regional projects located throughout United States, each with differing atmospheric pollution conditions resulting from variations in source emissions and meteorology. overall goal to elucidate source-receptor relationships processes leading PM accumulation on urban scales; thus...
Abstract. This study evaluates the significance of glyoxal acting as an intermediate species leading to secondary organic aerosol (SOA) formation from aromatic hydrocarbon photooxidation under humid conditions. Rapid SOA uptake onto aqueous (NH4)2SO4 seed particles is observed in agreement with previous studies; however, did not partition significantly (with or without seed) during within environmental chamber (RH less than 80%). Rather, influences by raising hydroxyl (OH) radical...
Abstract. Secondary organic aerosol (SOA) formation from atmospheric oxidation of isoprene has been the subject multiple studies in recent years; however, reactions other conjugated dienes emitted anthropogenic sources remain poorly understood. SOA photooxidation isoprene, isoprene-1-13C, 1,3-butadiene, and 2,3-dimethyl-1,3-butadiene is investigated for high NOx conditions. The yield measured 1,3-butadiene/NOx/H2O2 irradiation system (0.089–0.178) was close to or slightly higher than that...
Levoglucosan has been extensively used as a molecular marker of biomass burning in source-apportionment studies over the last few decades. However, recent suggest that atmospheric lifetime levoglucosan may be order only 1–2 days under summertime conditions relevant to prescribed/wildfires. Implications reactivity wintertime conditions, however, remain uncertain despite significant contributions domestic wood combustion air quality. This study presents smog chamber experiments investigate...
Abstract. The chemical and physical differences of secondary organic aerosol (SOA) formed at select isothermal temperatures (278 K, 300 313 K) are explored with respect to density, particle volatility, hygroscopicity, elemental composition. A transition point in SOA hygroscopicity composition is observed near 290–292 K as within an environmental chamber heated from 278 indicating the presence a thermally labile compound. No such points for produced or subsequently cooled K. lowest more than...
Innovative secondary organic aerosol (SOA) composition analysis methods normalizing yield and chemical on an aromatic ring basis are developed utilized to explore formation from oxidation of hydrocarbons. SOA revisited using 15 years University California, Riverside/CE-CERT environmental chamber data 17 hydrocarbons with HC:NO ranging 11.1 171 ppbC:ppb. is redefined in this work by the molecular weight all precursors [Formula: see text], where i hydrocarbon precursor. The normalization...