A5021255789- Atmospheric chemistry and aerosols
- Atmospheric and Environmental Gas Dynamics
- Atmospheric Ozone and Climate
- Atmospheric aerosols and clouds
- Air Quality and Health Impacts
- Arctic and Antarctic ice dynamics
- Mass Spectrometry Techniques and Applications
- Air Quality Monitoring and Forecasting
- Vehicle emissions and performance
- Hydrocarbon exploration and reservoir analysis
- Advanced Chemical Sensor Technologies
- Methane Hydrates and Related Phenomena
- Analytical Chemistry and Chromatography
- Marine and coastal ecosystems
- Cryospheric studies and observations
- Catalytic Processes in Materials Science
- Climate change and permafrost
- Spectroscopy and Quantum Chemical Studies
- Maritime Transport Emissions and Efficiency
- Analytical chemistry methods development
- Toxic Organic Pollutants Impact
- Electrohydrodynamics and Fluid Dynamics
- Molecular Junctions and Nanostructures
- Innovative Microfluidic and Catalytic Techniques Innovation
- Spectroscopy and Laser Applications
Colorado State University
2021-2025
Zero to Three
2023
Colorado State University System
2022
University of Toronto
2014-2021
Lawrence Berkeley National Laboratory
2018-2020
Berkeley College
2020
University of California, Berkeley
2020
Environment and Climate Change Canada
2019
Vancouver Island University
2013-2014
Abstract. Motivated by the need to predict how Arctic atmosphere will change in a warming world, this article summarizes recent advances made research consortium NETCARE (Network on Climate and Aerosols: Addressing Key Uncertainties Remote Canadian Environments) that contribute our fundamental understanding of aerosol particles as they relate climate forcing. The overall goal has been use an interdisciplinary approach encompassing extensive field observations range chemical transport, earth...
Summertime Arctic shipboard observations of oxygenated volatile organic compounds (OVOCs) such as acids, key precursors climatically active secondary aerosol (SOA), are consistent with a novel source OVOCs to the marine boundary layer via chemistry at sea surface microlayer. Although this has been studied in laboratory setting, acid emissions from microlayer have not previously observed ambient environments. Correlations between measurements OVOCs, including high levels formic acid,...
Abstract The Arctic region is a harbinger of global change and warming at rate higher than the average. While driven by increases in anthropogenic greenhouse gases' combination with local feedback mechanisms, short‐lived climate forcing agents, such as tropospheric aerosol, are also important drivers climate. aerosol‐climate impacts vary seasonally result interplay between aerosol different cloud types, available solar radiation, sea ice, surface albedo, lower latitude removal processes,...
The application of Electrospray and Electrosonic Spray Ionization Mass Spectrometry (ESI-MS ESSI-MS) to study accelerated reaction kinetics in droplets is examined using numerical models, new experimental data, prior literature.
Abstract. The summertime Arctic lower troposphere is a relatively pristine background aerosol environment dominated by nucleation and Aitken mode particles. Understanding the mechanisms that control formation growth of crucial for our ability to predict cloud properties therefore radiative balance climate. We present an analysis event observed in Canadian Archipelago during summer as part NETCARE project. Under stable clean atmospheric conditions, with low inversion heights, carbon monoxide...
Abstract The optical properties of ambient black carbon‐containing particles and the composition their associated coatings were investigated at a downtown site in Toronto, Canada, for 2 weeks June 2013. objective was to assess relationship between carbon (BC) coating composition/thickness absorption. influenced by emissions from local vehicular traffic, wildfires Quebec, transboundary fossil fuel combustion United States. Mass concentrations BC nonrefractory measured using soot...
Abstract Although it is known that soot particles are emitted in large quantities to the atmosphere, our understanding of their environmental effects limited by knowledge how composition subsequently altered through atmospheric processing. Here we present an on-line mass spectrometric study changing chemical hydrocarbon as they oxidized gas-phase ozone, and show surface-mediated loss rates adsorbed polycyclic aromatic hydrocarbons directly connected a significant increase particle redox...
Abstract. Observations addressing effects of aerosol particles on summertime Arctic clouds are limited. An airborne study, carried out during July 2014 from Resolute Bay, Nunavut, Canada, as part the Canadian NETCARE project, provides a comprehensive in situ look into some liquid clean environment summer. Median cloud droplet number concentrations (CDNC) 62 samples 10 cm−3 for low-altitude (clouds topped below 200 m) and 101 higher-altitude based above m). The lower activation size is ≤ 50...
Abstract. Ice nucleating particles (INPs) in the Arctic can influence climate and precipitation region; yet our understanding of concentrations sources INPs this region remain uncertain. In following, we (1) measured immersion mode Canadian marine boundary layer during summer 2014 on board CCGS Amundsen, (2) determined ratios surface areas mineral dust aerosol to sea spray aerosol, (3) investigated source using particle dispersion modelling. Average at −15, −20, −25 ∘C were 0.005, 0.044,...
Abstract. Size-resolved and vertical profile measurements of single particle chemical composition (sampling altitude range 50–3000 m) were conducted in July 2014 the Canadian high Arctic during an aircraft-based measurement campaign (NETCARE 2014). We deployed laser ablation aerosol mass spectrometer ALABAMA (vacuum aerodynamic diameter approximately 200–1000 nm) to identify different types their mixing states. On basis analysis, we found that a significant fraction (23 %) all analyzed...
Surfaces play a critical role in accelerating reaction rates micro-compartments.
Abstract. Understanding the impact of atmospheric black carbon (BC)-containing particles on human health and radiative forcing requires knowledge mixing state BC, including characteristics materials with which it is internally mixed. In this study, we examine refractory BC (rBC) other aerosol components in an urban environment (downtown Toronto) utilizing Aerodyne soot particle mass spectrometer equipped a light scattering module (LS-SP-AMS). k-means cluster analysis was used to classify...
Abstract. The soot-particle aerosol mass spectrometer (SP-AMS) uses an intra-cavity infrared laser to vaporize refractory black carbon (rBC) containing particles, making the particle beam–laser beam overlap critical in determining collection efficiency (CE) for rBC and associated non-refractory particulate matter (NR-PM). This work evaluates ability of SP-AMS quantify NR-PM internally mixed particles with different thicknesses organic coating. Using apparent relative ionization efficiencies...
Abstract We present vertically resolved observations of aerosol composition during pristine summertime Arctic background conditions. The methansulfonic acid (MSA)‐to‐sulfate ratio peaked near the surface (mean 0.10), indicating a contribution from ocean‐derived biogenic sulfur. Similarly, organic (OA)‐to‐sulfate increased toward 2.0). Both MSA‐to‐sulfate and OA‐to‐sulfate ratios were significantly correlated with FLEXPART‐WRF‐predicted air mass residence time over open water,...
Abstract. Black carbon (BC) contributes to Arctic warming, yet sources of BC and their geographic contributions remain uncertain. We interpret a series recent airborne (NETCARE 2015; PAMARCMiP 2009 2011 campaigns) ground-based measurements (at Alert, Barrow Ny-Ålesund) from multiple methods (thermal, laser incandescence light absorption) with the GEOS-Chem global chemical transport model its adjoint attribute BC. This is first comparison refractory (rBC) at Alert. The springtime performed by...
Abstract. Motivated by increasing levels of open ocean in the Arctic summer and lack prior altitude-resolved studies, extensive aerosol measurements were made during 11 flights NETCARE July 2014 airborne campaign from Resolute Bay, Nunavut. Flights included vertical profiles (60 to 3000 m above ground level) over ocean, fast ice, boundary layer clouds fogs. A general conclusion, observations particle numbers between 5 20 nm diameter (N5 − 20), is that ultrafine formation occurs readily...
Abstract. Biomass burning organic aerosol (BBOA) can be emitted from natural forest fires and human activities such as agricultural domestic energy generation. BBOA is strongly associated with atmospheric brown carbon (BrC) that absorbs near-ultraviolet visible light, resulting in significant impacts on regional visibility degradation radiative forcing. The mixing state of play a critical role the prediction optical properties. In this work, single-particle measurements Soot-Particle Aerosol...
Abstract. The vertical distribution of black carbon (BC) particles in the Arctic atmosphere is one key parameters controlling their radiative forcing and thus role climate change. This work investigates presence properties these light-absorbing aerosols over High Canadian (>70∘ N). Airborne campaigns were performed as part NETCARE project (Network on Climate Aerosols: Addressing Key Uncertainties Remote Environments) provided insights into variability distributions BC summer 2014 spring...
Abstract. Summertime Arctic aerosol size distributions are strongly controlled by natural regional emissions. Within this context, we use a chemical transport model with size-resolved microphysics (GEOS-Chem-TOMAS) to interpret measurements of from the Canadian Archipelago during summer 2016, as part “NETwork on Climate and Aerosols: Addressing key uncertainties in Remote Environments” (NETCARE) project. Our simulations suggest that condensation secondary organic (SOA) precursor vapors...
Chemical transformations in aerosols impact the lifetime of particle phase species, fate atmospheric pollutants, and both climate- health-relevant aerosol properties. Timescales for multiphase reactions ozone aqueous phases are governed by coupled kinetic processes between gas phase, interface, its bulk, which respond dynamically to reactive consumption O3. However, models reactivity often do not account nature processes. To examine these dynamics, we use new prior experimental observations...
Abstract. The climatic impacts of black carbon (BC) aerosol, an important absorber solar radiation in the atmosphere, remain poorly constrained and are intimately related to its particle-scale physical chemical properties. Using particle-resolved modelling informed by quantitative measurements from a soot-particle aerosol mass spectrometer, we confirm that mixing state (the distribution co-emitted amongst fresh BC-containing particles) at time emission significantly affects BC-aerosol...
Abstract. The sources, chemical transformations and removal mechanisms of aerosol transported to the Arctic are key factors that control aerosol–climate interactions. Our understanding sources processes is limited by a lack vertically resolved observations in remote regions. We present trace gases composition High springtime, made largely north 80∘ N, during NETCARE campaign. Trace gas gradients observed on these flights defined polar dome as 66–68∘ 30′ N below potential temperatures...
Abstract. The springtime composition of the Arctic lower troposphere is to a large extent controlled by transport midlatitude air masses into Arctic. In contrast, precipitation and natural sources play most important role during summer. Within region sloping isentropes create barrier horizontal transport, known as polar dome. dome varies in space time exhibits strong influence on from midlatitudes, enhancing winter inhibiting We analyzed aircraft-based trace gas measurements two NETCARE...
Polar environments are among the fastest changing regions on planet. It is a crucial time to make significant improvements in our understanding of how ocean and ice biogeochemical processes linked with atmosphere. This especially true over Antarctica Southern Ocean where observations severely limited environment far from anthropogenic influences. In this commentary, we outline major gaps knowledge, emerging research priorities, upcoming opportunities needs. We then give an overview...
Abstract. Transport of anthropogenic aerosol into the Arctic in spring months has potential to affect regional climate; however, modeling estimates direct radiative effect (DRE) are sensitive uncertainties mixing state black carbon (BC). A common approach previous studies is assume an entirely external mixture (all primarily scattering species separate particles from BC) or internal mixed same as BC). To provide constraints on size-resolved BC, we use airborne single-particle soot photometer...