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HONO-Measurements During the OS Field Campaign at AMS13

Informal Lunchtime Atmospheric Chemistry Discussion Series
Presented by:
Kevin Nikelski, Graduate Student
April 7th, 2015 at Noon - 1PM
317 Petrie Science and Eng. Bldg.

Description: Nitrous acid (HONO) is of particular relevance to atmospheric chemistry in regards to its significant contribution to photochemical production of the OH radical, which serves as the main daytime oxidant in the troposphere. Many studies have reported observing significant HONO mixing ratios during daylight hours, which could be due to an as yet unexplained continuous daytime source and/or indicating a method of HONO uptake and storage during the night with subsequent release the next day. In this talk, I will discuss HONO measurements from Aug 17th- Sept 11th during the OS field campaign in the region near Fort McMurray Alberta at the AMS13 ground site. Continue reading

Airborne LIDAR measurements of aerosol and ozone

Informal Lunchtime Atmospheric Chemistry Discussion Series
Presented by:  Monika Aggarwal, Graduate Student @ Prof. Whiteway
Tuesday, Feb. 17th, Noon-1PM, 317 Petrie

Lidar measurements of ozone and aerosol were conducted from a Twin Otter
aircraft above northern Alberta. The field campaign was carried out with a total
of five flights, during the period between August 22 and August 26, 2013.
Significant amounts of aerosol were observed within the boundary layer,
up to a height of 1.1 km above ground level, but the ozone concentration
remained at or below background levels (40 ppbv). On August 24th the lidar
observed a separated layer of aerosol above the boundary layer, at a height
of 1.8 km above ground level, in which the ozone mixing ratio increased
to 70 ppbv. Backward trajectory calculations revealed that the air
containing this separated aerosol layer had passed over an area of forest fires.
Directly below the layer of forest fire smoke, in the pollution, the
measured ozone mixing ratio was lower than the background levels (<35 ppbv).

Three months of research exchange at Forschungszentrum Juelich: A sneak peek inside

Informal Lunchtime Atmospheric Chemistry Discussion Series
Presented by:  Mehrnaz Sarrafzadeh, Graduate Student
Tuesday, Feb. 3rd. Noon - 1PM - 317 Petrie

Description:  A three month research exchange was conducted at Forschungszentrum Jülich in Jülich, Germany to extend our knowledge of secondary organic aerosols (SOA) formation from beta-pinene photo-oxidation. SOA constitute a substantial fraction of ambient organic aerosols and are known to adversely affect visibility, climate and health. Despite extensive studies, the chemical composition and mechanism of SOA formation is not well understood.
Experiments were carried out under atmospherically relevant conditions in the Jülich Plant Atmosphere Chamber (JPAC) to investigate the SOA mass yield as well as climate parameters that impact mass yield​,​ such as NOx. Furthermore, ​the formation and detection of highly oxidized multifunctional products which contribute significantly to atmospheric SOA​ is briefly discussed​. ​

Estimating surface fluxes of CO2 and CH4 in the Hudson Bay Lowlands using a Lagrangian Particle Dispersion Model (STILT)

Informal Lunchtime Atmospheric Chemistry Discussion Series

Presented by:
Olalekan Balogun, Graduate Student, Geography
Tuesday, January 20th, 2015
317 Petrie Science and Engineering

The Hudson Bay Lowlands (HBL) region of Canada is the second largest semi-continuous wetland region in the world covering an area of 320, 000 km2. Consequently, there has been much interest in quantifying wetland emissions and fluxes from the HBL. Such studies are vital to a better understanding of greenhouse gas emission estimates and fluxes from northern wetlands; a prerequisite for accurate global climate change modelling and predictions by GCMs.
In this study, we employ a Lagrangian particle dispersion model (STILT) coupled to the North American Regional Reanalysis (NARR) dataset to model CO2 and CH4 atmospheric concentrations in the Hudson Bay Lowlands. The model results are compared with actual measurements from the Churchill Northern Studies Centre (CNSC) microwave tower. Furthermore, surface fluxes of these gases are estimated and mapped to show the upstream influences on the measured mixing ratios at the CNSC microwave tower in Churchill Manitoba.

Bring your own coffee/tea mug. Cookies will be served.

Laboratory Studies of Carbon Kinetic Isotope Effects on the Production Mechanism of Particulate Phenolic Compounds Formed by Toluene Photooxidation: A Tool to Constrain Reaction Pathways

Satoshi Irei, Jochen Rudolph, Lin Huang, Janeen Auld, Fabrice Collin and Donald Hastie

The Journal of Physical Chemistry A, 2015, 119 (1), pp. 5-13, DOI: 10.1021/jp5104609.

In this study, we examined compound-specific stable carbon isotope ratios for phenolic compounds in secondary organic aerosol (SOA) formed by photooxidation of isotope-label-free toluene. SOA generated by photooxidation of toluene using a continuous-flow reactor and an 8 m(3) indoor smog chamber was collected on filters, which were extracted with acetonitrile for compound-specific analysis. Eight phenolic compounds were identified in the extracts using a gas chromatograph coupled with a mass spectrometer, and their compound-specific stable carbon isotope ratios were determined using a gas chromatograph coupled with a combustion furnace followed by an isotope ratio mass spectrometer. The majority of products, including methylnitrophenols and methylnitrocatechols, were isotopically depleted by 5-6‰ compared to the initial isotope ratio of toluene, whereas the isotope ratio for 4-nitrophenol remained identical to that of toluene. On the basis of the reaction mechanisms proposed in previous reports, stable carbon isotope ratios of these products were calculated. By comparing the observed isotope ratios with the predicted isotope ratios, we explored possible production pathways for the particulate phenolic compounds.

Lake Erie Windfarms: Some preliminary modelling using COHERENS

Informal Lunchtime Atmospheric Chemistry Discussion Series

Presented by
Soudeh Afsharian (Phd. Candidate)
Tuesday, January 13, 2015 @ 12:00 pm - 1:00 pm
317 Petrie Science and Engineering Bldg.
York University

Description:  The potential of offshore wind is enormous. It could meet Europe's energy demand seven times over, and the United States energy demand four times over.
Offshore wind is a relatively new technology, More than 90% of the world's offshore wind power is currently installed off northern Europe. Most of the rest is in two "demonstration" projects off China's east coast although there are plans in the USA (Atlantic - Cape Cod and Lake Erie - Cleveland).
The key benefits of offshore wind are:
● The wind resource offshore is generally much greater, thus generating more energy from fewer turbines;
● Most of the world's largest cities are located near a coastline. Offshore wind is suitable for large scale development near the major demand centers, avoiding the need for long transmission lines;
● Building wind farms offshore makes sense in very densely populated coastal regions with high property values, because high property values make on shore development expensive and sometimes leads to public opposition (especially in Ontario!).
● At present there is a moratorium on offshore wind farm developments in Ontario but OMECC have recently announces two RFPs related to offshore wind farms so things may change. If there were large scale wind farm development in Lake Erie (because it is relatively shallow) what impacts would this have on lake circulation and mixing?

On land the Erie Shores Wind Farm was one of the first in Ontario. It allows
200,000 tonnes of carbon dioxide emissions, the major contributor to global warming, to be displaced from the environment annually.
COHERENS (A Coupled Hydrodynamical-Ecological Model for Regional and Shelf Seas) is numerical software that we plan to use in order to simulate the effects of the wind farms on the circulation and mixing of the water. We are working on Lake Erie, since this has the highest potential for offshore wind turbine installation due to its location and as is the shallowest among the Great Lakes. At this stage we can
provide good results of simulating the heat fluxes, temperature, water current and thermocline by running the model in a 1-D condition driven by hourly wind and air temperature data. Our next step will be to extend this simulation to the 3D situation.

Quantifying sources of methane using cavity ring-down spectroscopy

Informal Lunchtime Atmospheric Chemistry Discussion Series

Presented by
Sabour Baray (M.Sc. Candidate)
Centre for Atmospheric Chemistry
Tuesday, November 25, 2014 @ 12:00 pm - 1:00 pm
317 Petrie Science and Engineering Bldg.
York University


Of the compounds most influential in radiative forcing, methane is 3rd overall next to water and carbon dioxide. While background levels of methane have been relatively stable since the 1980’s, a recent and poorly-understood spike in the mixing ratio has been observed as of 2007. In these studies sources of methane were investigated in both industrial and urban environments. In the summer of 2013 during the Oil Sands field study led by Environment Canada, aircraft and ground-site measurements of multiple species, including CO2, CH4, CO and H2O were made by a Picarro cavity ring-down spectrometer (CRDS) instrument. Methane peaks of up to 4.3 parts per trillion were observed, and analysis has been ongoing in order to paint a 3 dimensional picture of emissions and to differentiate between various sources present. In the fall of 2014, an urban field study in the Greater Toronto Area was completed with the same CRDS instrument in order to investigate methane emissions from various classes of vehicles. A range of emissions factors were observed up to 3 times the recommended values in the Canadian inventory.

A Phd candidate goes abroad: Four months of learning about differential optical absorption spectroscopy and optimal estimation methods in Heidelberg, Germany

Informal Lunchtime Atmospheric Chemistry Discussion Series

Presented by
Zoey Davis, Phd. Graduate Student
Chemistry Department

Tuesday, November 11, 2014 @ 12:00 pm - 1:00 pm
317 Petrie Science and Engineering Bldg.
York University


A four month exchange was undertaken at the Institut für Umweltphysik at Heidelberg University, Germany in order to learn more about and implement Differential Optical Absorption Spectroscopy (DOAS) analysis techniques on Multi-Axis DOAS (MAX-DOAS) measurements from the Alberta Oil Sands (AOS) and retrieve profiles of boundary layer aerosol extinction and trace gases from these measurements using an optimal estimation method. The scarcity of independent measurements of industrial air pollution emissions in the AOS limits our understanding of the impacts of the area’s industrial activity and the ability to make quality environmental management decisions. The dataset was collected during the 2013 Environment Canada AOS air quality campaign and represents the first retrievals of vertical profiles of SO2 and NO2 from MAX-DOAS measurements in the AOS. This talk will present improvements to our methodology for trace gas retrievals using DOAS analysis. The basic theory of the optimal estimation retrieval method and a case study from preliminary retrieval results will be presented. Potential methods for estimation of trace gas emissions from particular AOS facilities using the retrieved trace gas profiles will be discussed.


What to do in Europe for 3 months: Tales from an IACPES Research Exchange

Informal Lunchtime Atmospheric Chemistry Discussion Series

Presented by
Dr. Marina Saccon
York University, Chemistry Department

October 28, 2014 @ 12:00 pm - 1:00 PM
317 Petrie Science and Engineering Bldg.
York University

A 3 month exchange was completed at the Forschungszentrum Jülich to conduct kinetic experiments of reactions of atmospheric volatile organic compounds (VOC). During the last decade, the number of publications using carbon isotope ratio measurements in studies of atmospheric VOC has been increasing substantially. Knowing the kinetic Continue reading