A5047534071- Atmospheric chemistry and aerosols
- Air Quality and Health Impacts
- Atmospheric and Environmental Gas Dynamics
- Vehicle emissions and performance
- Atmospheric aerosols and clouds
- Atmospheric Ozone and Climate
- Air Quality Monitoring and Forecasting
- Petroleum Processing and Analysis
- Toxic Organic Pollutants Impact
- Hydrocarbon exploration and reservoir analysis
- Oil Spill Detection and Mitigation
- Odor and Emission Control Technologies
- Fire effects on ecosystems
- Indoor Air Quality and Microbial Exposure
- Wind and Air Flow Studies
- Oil, Gas, and Environmental Issues
- Plant responses to elevated CO2
- Ocean Acidification Effects and Responses
- Advanced Aircraft Design and Technologies
- Spectroscopy and Laser Applications
- Geochemistry and Geologic Mapping
- Aeolian processes and effects
- Meteorological Phenomena and Simulations
- Industrial Gas Emission Control
- Air Traffic Management and Optimization
Environment and Climate Change Canada
2016-2025
Peking University
2023
York University
2003-2005
The uptake of gaseous glyoxal onto particulate matter has been studied in laboratory experiments under conditions relevant to the ambient atmosphere using an aerosol mass spectrometer. growth rates and reactive coefficients, γ, were derived by fitting a model particle experimental data. Organic varied from 1.05 × 10 −11 23.1 μg −1 min presence ∼5 ppb glyoxal. Uptake coefficients (γ) 8.0 −4 7.3 −3 with median γ = 2.9 , observed for (NH 4 ) 2 SO seed aerosols at 55% relative humidity....
Reactive uptake of glyoxal onto particulate matter has been studied in laboratory experiments a 2 m3 Teflon reaction chamber. Inorganic seed particles different composition were utilized, including (NH4)2SO4, (NH4)2SO4/H2SO4, NaNO3, and simulated sea salt, while the relative humidity acid concentration varied. The organic growing was measured situ with an aerosol mass spectrometer, providing particle spectra as means product identification. Aerosol physical characteristics also differential...
Abstract. Cloud condensation nuclei (CCN) concentrations were measured at Egbert, a rural site in Ontario, Canada during the spring of 2007. The CCN compared to values predicted from aerosol chemical composition and size distribution using κ-Köhler theory, with specific goal this work being determine hygroscopic parameter (κ) oxygenated organic component aerosol, assuming that oxygenation drives hygroscopicity for entire fraction aerosol. component, as determined by an Aerodyne mass...
In the atmosphere, volatile organic compounds such as glyoxal can partition into aqueous droplets containing significant levels of inorganic salts. Upon droplet evaporation, both organics and ions become highly concentrated, accelerating reactions between them. To demonstrate this process, we investigated formation organo-nitrogen light absorbing materials in evaporating different ammonium salts including (NH4)2SO4, NH4NO3, NH4Cl. Our results that glyoxal-(NH4)2SO4 produce species on a time...
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. Measurements of aerosol composition, volatile organic compounds, and CO are used to determine biogenic secondary (SOA) concentrations at a rural site 70 km north Toronto. These SOA levels many times higher than past observations occur during period increasing temperatures outflow from Northern Ontario Quebec forests in early summer. A regional chemical transport model approximately predicts the event timing accurately loading, identifying precursors as monoterpene emissions...
Abstract. The Whistler Aerosol and Cloud Study (WACS 2010), included intensive measurements of trace gases particles at two sites on Mountain. Between 6–11 July 2010 there was a sustained high-pressure system over the region with cloud-free conditions highest temperatures study. During this period, organic aerosol concentrations rose from <1 μg m−3 to ∼6 m−3. Precursor gas composition show that these organics were almost entirely secondary biogenic nature. Throughout July, anthropogenic...
Abstract. As a class of brown carbon, organonitrogen compounds originating from the heterogeneous uptake NH3 by secondary organic aerosol (SOA) have received significant attention recently. In current work, particulate formation during ozonolysis α-pinene and OH oxidation m-xylene in presence ammonia (34–125 ppb) was studied smog chamber equipped with high resolution time-of-flight mass spectrometer quantum cascade laser instrument. A large diversity nitrogen-containing (NOC) fragments...
Significance Validation of volatile organic compound (VOC) emission reports, especially from large industrial facilities, is rarely attempted. Given uncertainties in their evaluation and validation will build confidence inventories. It shown that a top-down approach can provide measurement-based rates for such validation. Comparisons with reports Alberta oil sands surface mining facilities revealed significant differences VOC emissions between reports. Comparison species using currently...
Abstract. The water-soluble fractions of aerosol filter samples and cloud water collected during the Whistler Aerosol Cloud Study (WACS 2010) were analyzed using an Aerodyne mass spectrometer (AMS). This is first study to report AMS organic spectra re-aerosolized water, make direct comparison between at same location. In general, very similar those less volatile organics. By a photochemical reactor oxidize both extracts we find evidence that fragmentation organics in increases their...
Abstract. An Aerodyne High Resolution Time-of-Flight Aerosol Mass Spectrometer (HR-ToF-AMS) was deployed at the peak of Whistler Mountain (2182 m above sea level), British Columbia, from 19 April to 16 May 2006, as part Intercontinental Chemical Transport Experiment Phase B (INTEX-B) campaign. The mass concentrations and size distributions non-refractory submicron particle (NR-PM1) species (i.e., sulfate, nitrate, ammonium, chloride, organics) were measured in situ 10-min time resolution....
Heterogeneous reactions between OH radicals and emerging flame retardant compounds coated on inert particles have been investigated. Organophosphate esters (OPEs) including triphenyl phosphate (TPhP), tris-2-ethylhexyl (TEHP), tris-1,3-dichloro-2-propyl (TDCPP) were (NH4)2SO4 exposed to in a photochemical flow tube at 298 K (38.0 ± 2.0) % RH. The degradation of these particle-bound OPEs was observed as result exposure, measured using Time-of-Flight Aerosol Mass Spectrometer. derived...
Abstract. We describe the results from online measurements of nitrated phenols using a time-of-flight chemical ionization mass spectrometer (ToF-CIMS) with acetate as reagent ion in an oil and gas production region January February 2014. Strong diurnal profiles were observed for phenols, concentration maxima at night. Based on known markers (CH4, NOx, CO2), primary emissions not important this study. A box model was used to simulate secondary formation phenol, nitrophenol (NP),...
Abstract A large data set including surface, aircraft, and laboratory observations of the atomic oxygen‐to‐carbon (O:C) hydrogen‐to‐carbon (H:C) ratios organic aerosol (OA) is synthesized corrected using a recently reported method. The whole indicates wide range OA oxidation trajectory in Van Krevelen diagram, characterized by slope −0.6, with variation across campaigns. We show that both source aged types explains some key differences observed different environments. However, typically fall...
The redox activity of diesel exhaust particles (DEP) collected from a light-duty passenger car engine was examined using the dithiothreitol (DTT) assay. DEP highly redox-active, causing DTT to decay at rate 23-61 pmol min(-1) μg(-1) particle used in assay, which an order magnitude higher than ambient coarse and fine particulate matter (PM) downtown Toronto. Only 2-11% water-soluble portion, while remainder occurred black carbon surface. This is contrast redox-active secondary organic aerosol...
The particle infiltration efficiencies (PIE) of three passive and one active air samplers were evaluated under field conditions. A wide-range spectrometer operating in the 250–4140 nm range was used to acquire highly temporally resolved particle-number size distributions for different compared ambient air. Overall, four able a representative sample particles with PIEs 91.5 ± 13.7% GAPS Network sampler, 103 15.5% Lancaster University 89.6 13.4% conventional PS-1 high-volume sampler (Hi-Vol)....
The oil and gas (O&G) sector represents a large source of greenhouse (GHG) emissions globally. However, estimates O&G rely upon bottom-up approaches, are rarely evaluated through atmospheric measurements. Here, we use aircraft measurements over the Canadian sands (OS) to derive first top-down, measurement-based determination their annual CO2 intensities. results indicate that emission intensities for OS facilities 13-123% larger than those estimated using publically available data. This...
Pollution derived from car tires is of growing research interest due to its apparent omnipresence in the urban environment and associated toxicity. Studies have focused largely on occurrence these tire materials, deemed wear particles (TWPs), their chemicals aquatic environment. However, less attention has been paid atmospheric TWPs, which can remain airborne be transported over long distances. In addition, there are few studies pertaining gaseous contaminants originating wear, creating a...
Anthropogenic organic carbon emissions reporting has been largely limited to subsets of chemically speciated volatile compounds. However, new aircraft-based measurements revealed total gas-phase that exceed oil sands industry-reported values by 1900% over 6300%, the bulk which was due unaccounted-for intermediate-volatility and semivolatile Measured facility-wide represented approximately 1% extracted petroleum, resulting in equivalent from all other sources across Canada combined. These...
Dry deposition is an important yet poorly constrained process that removes reactive organic carbon from the atmosphere, making it unavailable for airborne chemical reactions and transferring to other environmental systems. Using aircraft-based measurement method, we provide large-scale estimates of total gas-phase rates fluxes. Observed downwind unconventional oil operations reached up 100 tC hour −1 , with fluxes exceeding 0.1 gC m −2 . The observed lifetimes (τ dep ) were short enough...