Improvements to our Understanding of Toronto-area Atmospheric Composition
Bibliographic record
Abstract
Using eleven years of trace gas column measurements at the University of Toronto Atmospheric Observatory (TAO), along with data from complementary sources, such as satellites, surface in situ measurements, and nearby rural column measurements, thisthesis aims to improve our understanding of the sources of air pollution and the causes of variability in atmospheric composition over the Toronto area.The relative influence of chemical production and direct emissions on Toronto-area O3 and CO were determined using GEOS-Chem model simulations. 28 pollution events (defined as enhanced O3 or CO lower-tropospheric (0-5 km) columns that coincided with surface O3 exceedances) were found in the TAO dataset between 2002 and 2010. O3 columns over Toronto during pollution events are influenced by urban and industrial anthropogenic NOx emissions, biogenic isoprene emissions from the eastern United States, and soil NOx emissions from the mid- and western United States. During pollution events, Toronto CO columns are greatly influenced by nearby fossil fuel emissions and isoprene oxidation. C2H6 columns are often enhanced during pollution events, as the sources of C2H6 are similar to those of O3 and CO. HCN columns are assumed to be enhanced in biomass burning plumes, and thus, aid in identifying transport of biomass burning emissions over Toronto. Sensitivity to meteorological conditions was examined as well, and five case studies were presented in detail.Passage of the polar vortex over the Toronto area was determined by increases in scaled potential vorticity (PV) that coincide with outliers in the HF stratospheric time series. Confirmed with polar PV maps and reductions in N2O stratospheric columns, 53 polar intrusion events were identified in the 2002 to 2013 TAO time series. The effect on HF, HCl, O3, and N2O was studied, and we found these events caused a significant increase in HF-column winter/spring variability, and a small increase (on average) in stratospheric O3 columns.The results of this thesis have contributed to improving our understanding of the causes and variability of ozone air quality and stratospheric ozone over a major metropolitan area.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.016 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one teacher head, not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".