Investigating reactive tropospheric nitrogen oxides by thermal-dissociation cavity ring-down spectroscopy
| dc.contributor.advisor | Osthoff, Hans D. | |
| dc.contributor.author | Gingerysty, Nicholas John Louis | |
| dc.contributor.committeemember | Gailer, Jürgen G. | |
| dc.contributor.committeemember | Kimura, Susana Y. | |
| dc.date | 2021-06 | |
| dc.date.accessioned | 2021-01-26T16:01:32Z | |
| dc.date.available | 2021-01-26T16:01:32Z | |
| dc.date.issued | 2021-01-18 | |
| dc.description.abstract | The nitrogen oxides are important trace constituents of the troposphere that originate mainly from anthropogenic sources. Accurate quantification techniques are needed to characterize their abundance and to assess their impact on air quality. This thesis describes a compact and portable source that delivers nitrous acid (HONO) in high purity (>95%). HONO is produced dynamically by reacting a gas stream containing < 1 part per million (by volume) HCl gas at relative humidity of 30% - 40% with solid sodium nitrite. The production of HONO and absence of impurities such as nitric oxide (NO), nitrogen dioxide (NO2) and nitrosyl chloride (ClNO) were verified by Fourier transform infrared (FTIR) and thermal dissociation cavity ring-down spectroscopy (TD CRDS). The interference from HONO in the measurement of NO2 by photolytic conversion with chemiluminescence detection (P-CL) was investigated in two prototype converters. The first used radiation centred around 395 nm, common in P-CL. The second utilized 415 nm light, where the overlap with the HONO absorption spectrum and expected HONO interference are lower. Mixing ratios of NO2, NOx and HONO entering and exiting the converters were quantified by TD-CRDS. Both converters exhibited high NO2 conversion efficiency (CFNO2 >90%). Plots of CF against flow rate delivered photolysis frequencies of 4.2 s-1 and 2.9 s-1 for NO2 and 0.25 s-1 and 0.10 s-1 for HONO at 395 nm and 415 nm, respectively. The CFHONO was larger than predicted implying that measurements of NO2 by P-CL overestimate NO2 concentrations. Mixing ratios of nitrogen oxides were quantified during the SNOWDOGS campaign in Fort MacKay, AB, in January 2020. The group's TD-CRDS was modified to simultaneously quantify mixing ratios of NO2, HNO3, gas phase NOy, and total NOy (including particulate nitrate). High nitrogen oxide concentrations at night and faster than expected daytime conversion of NO2 to nitric acid (HNO3) and particulate nitrate were observed, indicating that the nitrogen oxides are processed primarily by photochemical reactions in polluted regions at high latitude during winter. | en_US |
| dc.identifier.citation | Gingerysty, N. J. L. (2021). Investigating reactive tropospheric nitrogen oxides by thermal-dissociation cavity ring-down spectroscopy (Master's thesis, University of Calgary, Calgary, Canada). Retrieved from https://prism.ucalgary.ca. | en_US |
| dc.identifier.doi | http://dx.doi.org/10.11575/PRISM/38580 | |
| dc.identifier.uri | http://hdl.handle.net/1880/113012 | |
| dc.language.iso | eng | en_US |
| dc.publisher.faculty | Science | en_US |
| dc.publisher.institution | University of Calgary | en |
| dc.rights | University of Calgary graduate students retain copyright ownership and moral rights for their thesis. You may use this material in any way that is permitted by the Copyright Act or through licensing that has been assigned to the document. For uses that are not allowable under copyright legislation or licensing, you are required to seek permission. | en_US |
| dc.subject | Chemistry | en_US |
| dc.subject | nitrogen oxides | en_US |
| dc.subject | nitrous acid | en_US |
| dc.subject | cavity ring-down spectroscopy | en_US |
| dc.subject | photolytic conversion | en_US |
| dc.subject | Athabasca oil sands | en_US |
| dc.subject.classification | Chemistry--Analytical | en_US |
| dc.subject.classification | Atmospheric Science | en_US |
| dc.title | Investigating reactive tropospheric nitrogen oxides by thermal-dissociation cavity ring-down spectroscopy | en_US |
| dc.type | master thesis | en_US |
| thesis.degree.discipline | Chemistry | en_US |
| thesis.degree.grantor | University of Calgary | en_US |
| thesis.degree.name | Master of Science (MSc) | en_US |
| ucalgary.item.requestcopy | true | en_US |