A5008826355- Atmospheric chemistry and aerosols
- Air Quality and Health Impacts
- Air Quality Monitoring and Forecasting
- Atmospheric aerosols and clouds
- Atmospheric Ozone and Climate
- Vehicle emissions and performance
- Atmospheric and Environmental Gas Dynamics
- Indoor Air Quality and Microbial Exposure
- Fire effects on ecosystems
- Toxic Organic Pollutants Impact
- Odor and Emission Control Technologies
- Marine and coastal ecosystems
- Allergic Rhinitis and Sensitization
- Energy and Environment Impacts
- Crystallization and Solubility Studies
- Fire dynamics and safety research
- X-ray Diffraction in Crystallography
- Water Quality and Resources Studies
- Catalytic Processes in Materials Science
- Muscle activation and electromyography studies
- Healthcare and Environmental Waste Management
- Aeolian processes and effects
- Advanced Chemical Sensor Technologies
- Caribbean history, culture, and politics
- Advanced Sensor and Energy Harvesting Materials
University of Iowa
2016-2025
University of Guelph
2025
University of North Carolina at Chapel Hill
2023
Engineering and Physical Sciences Research Council
2019-2020
Bristol Robotics Laboratory
2019-2020
Yale University
2019
Iowa City Public Library
2016-2018
Iowa Policy Project
2014
University of Wisconsin–Madison
2007-2013
University of Utah
2012
The study uses satellite observations, global assimilated aerosol data sets, Atmospheric Brown Clouds (ABC) observatories, a Monte Carlo aerosol‐cloud‐radiation model and regional chemical transport (STEM‐2K) to characterize the spatial extent of brown clouds, megacity ABC hot spots, composition direct radiative forcing. It presents first annual cycle observations forcing from observatories in Indo‐Asia‐Pacific regions. East Asia, Indo‐Gangetic Plains, Indonesian region, southern Africa...
Ambient sampling was conducted in Riverside, California during the 2005 Study of Organic Aerosols Riverside to characterize composition and sources organic aerosol using a variety state-of-the-art instrumentation source apportionment techniques. The secondary (SOA) mass is estimated by elemental carbon monoxide tracer methods, water soluble content, chemical balance molecular markers, positive matrix factorization high-resolution spectrometer data. Estimates obtained from each these methods...
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...
Abstract. A suite of offline and real-time gas- particle-phase measurements was deployed at Look Rock, Tennessee (TN), during the 2013 Southern Oxidant Aerosol Study (SOAS) to examine effects anthropogenic emissions on isoprene-derived secondary organic aerosol (SOA) formation. High- low-time-resolution PM2.5 samples were collected for analysis known tracer compounds in SOA by gas chromatography/electron ionization-mass spectrometry (GC/EI-MS) ultra performance liquid chromatography/diode...
Abstract. Single-scattering albedo (SSA) and absorption Ångström exponent (AAE) are two critical parameters in determining the impact of absorbing aerosol on Earth's radiative balance. Aerosol emitted by biomass burning represent a significant fraction globally, but it remains difficult to accurately predict SSA AAE for aerosol. Black carbon (BC), brown (BrC), non-absorbing coatings all make substantial contributions coefficient cannot be directly predicted based fuel type because they...
Abstract. Peat fires in Southeast Asia have become a major annual source of trace gases and particles to the regional–global atmosphere. The assessment their influence on atmospheric chemistry, climate, air quality, health has been uncertain partly due lack field measurements smoke characteristics. During strong 2015 El Niño event we deployed mobile sampling team Indonesian province Central Kalimantan island Borneo made first, or rare, gases, aerosol optical properties, mass emissions for...
In the present study, formation of aromatic organosulfates (OSs) from photo-oxidation polycyclic hydrocarbons (PAHs) was investigated. Naphthalene (NAP) and 2-methylnaphthalene (2-MeNAP), two most abundant gas-phase PAHs thought to represent "missing" sources urban SOA, were photochemically oxidized in an outdoor smog chamber facility presence nonacidified acidified sulfate seed aerosol. Effects aerosol composition, acidity relative humidity on OS examined. Chemical characterization SOA...
Brown carbon (BrC) has recently emerged as an important light-absorbing aerosol. This study provides interannual and seasonal variations in light absorption properties, chemical composition, sources of water-soluble BrC (WS-BrC) based on PM10 samples collected Godavari, Nepal, from April 2012 to May 2014. The mass efficiency WS-BrC at 365 nm (MAE365) shows a clear variability, with the highest MAE365 1.05 ± 0.21 m2 g–1 premonsoon season lowest monsoon (0.59 0.16 g–1). higher values...
The inclusion of organic compounds in freshly emitted sea spray aerosol (SSA) has been shown to be size-dependent, with an increasing fraction smaller particles. Here we have used electrospray ionization-high resolution mass spectrometry negative ion mode identify nascent collected throughout a 25 day mesocosm experiment. Over 280 from ten major homologous series were tentatively identified, including saturated (C8–C24) and unsaturated (C12–C22) fatty acids, acid derivatives (including...
Abstract. Organic carbon (OC) comprises a large fraction of fine particulate matter (PM2.5) in Mexico City. Daily and select 12-h PM2.5 samples were collected urban peripheral sites City from 17–30 March 2006. Samples analyzed for OC elemental (EC) using thermal-optical filter-based methods. Real-time water-soluble organic (WSOC) was at the site. compounds, particularly molecular markers, quantified by soxhlet extraction with methanol dichloromethane, derivitization, gas chromatography mass...
Abstract. The Nepal Ambient Monitoring and Source Testing Experiment (NAMaSTE) campaign took place in around the Kathmandu Valley Indo-Gangetic Plain (IGP) of southern during April 2015. source characterization phase targeted numerous important but undersampled (and often inefficient) combustion sources that are widespread developing world such as cooking with a variety stoves solid fuels, brick kilns, open burning municipal waste (a.k.a. trash or garbage burning), crop residue burning,...
Abstract Emission rates and properties of ice nucleating particles (INPs) are required for proper representation aerosol–cloud interactions in atmospheric models. Few investigations have quantified marine INP emissions, a potentially important source remote oceanic regions. Previous studies suggested INPs sea spray aerosol (SSA) linked to biological activity. This proposed link was explored this study by measuring emissions from nascent SSA during phytoplankton blooms two mesocosm...
Abstract. Combustion of fuels in the residential sector for cooking and heating results emission aerosol precursors impacting air quality, human health, climate. Residential emissions are dominated by combustion solid fuels. We use a global microphysics model to simulate impact fuel on atmospheric year 2000. The underestimates black carbon (BC) organic (OC) mass concentrations observed over Asia, Eastern Europe, Africa, with better prediction when carbonaceous from doubled. Observed seasonal...
Abstract. We report the formation of aliphatic organosulfates (OSs) in secondary organic aerosol (SOA) from photooxidation C10–C12 alkanes. The results complement those our laboratories reporting OSs and sulfonates gas-phase oxidation polycyclic aromatic hydrocarbons (PAHs). Both studies strongly support anthropogenic precursors, as hypothesized on basis recent field which were detected fine collected several major urban locations. In this study, dodecane, cyclodecane decalin, considered to...
Understanding the interactions of water with atmospheric aerosols is crucial for determining size, physical state, reactivity, and climate impacts this important component Earth's atmosphere. Here we show that uptake hygroscopic growth multicomponent, atmospherically relevant particles can be size dependent when comparing 100 nm versus ca. 6 μm sized particles. It was determined composed ammonium sulfate succinic acid a mixture chlorides typical marine environment size-dependent behavior....
Abstract. The Nepal Ambient Monitoring and Source Testing Experiment (NAMaSTE) characterized widespread under-sampled combustion sources common to South Asia, including brick kilns, garbage burning, diesel gasoline generators, groundwater pumps, idling motorcycles, traditional modern cooking stoves fires, crop residue heating fire. Fuel-based emission factors (EFs; with units of pollutant mass emitted per kilogram fuel combusted) were determined for fine particulate matter (PM2.5), organic...
Abstract. The meso-scale chemistry-transport model CHIMERE is used to assess our understanding of major sources and formation processes leading a fairly large amount organic aerosols – OA, including primary OA (POA) secondary (SOA) observed in Mexico City during the MILAGRO field project (March 2006). Chemical analyses submicron from aerosol mass spectrometers (AMS) indicate that particles found basin contain fraction oxygenated species (OOA) which have strong correspondence with SOA, their...
Abstract. Transport of aerosols in pollution plumes from the mainland Asian continent was observed situ at Jeju, South Korea during Cheju Brown Cloud Plume-Asian Monsoon Experiment (CAPMEX) field campaign throughout August and September 2008 using a 3-laser photoacoustic spectrometer (PASS-3), chemical filter analysis, size distributions. The PASS-3 directly measures effects morphology (e.g. coatings) on light absorption that traditional filter-based instruments are unable to address. mixed...
In summer 2012, a landfill liner comprising an estimated 1.3 million shredded tires burned in Iowa City, Iowa. During the fire, continuous monitoring and laboratory measurements were used to characterize gaseous particulate emissions provide new insights into qualitative nature of smoke quantity pollutants emitted. Significant enrichments ambient concentrations CO, CO2, SO2, particle number (PN), fine (PM2.5) mass, elemental carbon (EC), polycyclic aromatic hydrocarbons (PAH) observed. For...
In the southeastern US, substantial emissions of isoprene from deciduous trees undergo atmospheric oxidation to form secondary organic aerosol (SOA) that contributes fine particulate matter (PM2.5). Laboratory studies have revealed anthropogenic pollutants, such as sulfur dioxide (SO2), oxides nitrogen (NO x ), and acidity, can enhance SOA formation hydroxyl radical (OH)-initiated isoprene; however, mechanisms by which specific pollutants in ambient PM2.5 remain unclear. As one aspect an...