Atmospheric ammonia measurements in Houston, TX using an external-cavity quantum cascade laser-based sensor
In order to improve the current understanding of the dynamics of ammonia (NH<sub>3</sub>) in a major industrial and urban area, intensive measurements of atmospheric NH<sub>3</sub> were conducted in Houston during two sampling periods (12 Febru...
| Main Authors: | , , , , , |
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| Format: | Article |
| Language: | English |
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Copernicus Publications
2011-09-01
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| Series: | Atmospheric Chemistry and Physics |
| Online Access: | http://www.atmos-chem-phys.net/11/9721/2011/acp-11-9721-2011.pdf |
| _version_ | 1818259732533608448 |
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| author | L. Gong R. Lewicki R. J. Griffin J. H. Flynn B. L. Lefer F. K. Tittel |
| author_facet | L. Gong R. Lewicki R. J. Griffin J. H. Flynn B. L. Lefer F. K. Tittel |
| author_sort | L. Gong |
| collection | DOAJ |
| description | In order to improve the current understanding of the dynamics of ammonia (NH<sub>3</sub>) in a major industrial and urban area, intensive measurements of atmospheric NH<sub>3</sub> were conducted in Houston during two sampling periods (12 February 2010–1 March 2010 and 5 August 2010–25 September 2010). The measurements were performed with a 10.4-μm external cavity quantum cascade laser (EC-QCL)-based sensor employing conventional photo-acoustic spectroscopy. The mixing ratio of NH<sub>3</sub> ranged from 0.1 to 8.7 ppb with a mean of 2.4 ± 1.2 ppb in winter and ranged from 0.2 to 27.1 ppb with a mean of 3.1 ± 2.9 ppb in summer. The larger levels in summer probably are due to higher ambient temperature. A notable morning increase and a mid-day decrease were observed in the diurnal profile of NH<sub>3</sub> mixing ratios. Motor vehicles were found to be major contributors to the elevated levels during morning rush hours in winter. However, changes in vehicular catalytic converter performance and other local or regional emission sources from different wind directions governed the behavior of NH<sub>3</sub> during morning rush hours in summer. There was a large amount of variability, particularly in summer, with several episodes of elevated NH<sub>3</sub> mixing ratios that could be linked to industrial facilities. A considerable discrepancy in NH<sub>3</sub> mixing ratios existed between weekdays and weekends. This study suggests that NH<sub>3</sub> mixing ratios in Houston occasionally exceeded previous modeling predictions when sporadic and substantial enhancements occurred, potentially causing profound effects on particulate matter formation and local air quality. |
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| id | doaj.art-f9a5449d612d4f10b01d67041a01fdf1 |
| institution | Directory Open Access Journal |
| issn | 1680-7316 1680-7324 |
| language | English |
| last_indexed | 2024-12-12T18:20:07Z |
| publishDate | 2011-09-01 |
| publisher | Copernicus Publications |
| record_format | Article |
| series | Atmospheric Chemistry and Physics |
| spelling | doaj.art-f9a5449d612d4f10b01d67041a01fdf12022-12-22T00:16:10ZengCopernicus PublicationsAtmospheric Chemistry and Physics1680-73161680-73242011-09-0111189721973310.5194/acp-11-9721-2011Atmospheric ammonia measurements in Houston, TX using an external-cavity quantum cascade laser-based sensorL. GongR. LewickiR. J. GriffinJ. H. FlynnB. L. LeferF. K. TittelIn order to improve the current understanding of the dynamics of ammonia (NH<sub>3</sub>) in a major industrial and urban area, intensive measurements of atmospheric NH<sub>3</sub> were conducted in Houston during two sampling periods (12 February 2010–1 March 2010 and 5 August 2010–25 September 2010). The measurements were performed with a 10.4-μm external cavity quantum cascade laser (EC-QCL)-based sensor employing conventional photo-acoustic spectroscopy. The mixing ratio of NH<sub>3</sub> ranged from 0.1 to 8.7 ppb with a mean of 2.4 ± 1.2 ppb in winter and ranged from 0.2 to 27.1 ppb with a mean of 3.1 ± 2.9 ppb in summer. The larger levels in summer probably are due to higher ambient temperature. A notable morning increase and a mid-day decrease were observed in the diurnal profile of NH<sub>3</sub> mixing ratios. Motor vehicles were found to be major contributors to the elevated levels during morning rush hours in winter. However, changes in vehicular catalytic converter performance and other local or regional emission sources from different wind directions governed the behavior of NH<sub>3</sub> during morning rush hours in summer. There was a large amount of variability, particularly in summer, with several episodes of elevated NH<sub>3</sub> mixing ratios that could be linked to industrial facilities. A considerable discrepancy in NH<sub>3</sub> mixing ratios existed between weekdays and weekends. This study suggests that NH<sub>3</sub> mixing ratios in Houston occasionally exceeded previous modeling predictions when sporadic and substantial enhancements occurred, potentially causing profound effects on particulate matter formation and local air quality.http://www.atmos-chem-phys.net/11/9721/2011/acp-11-9721-2011.pdf |
| spellingShingle | L. Gong R. Lewicki R. J. Griffin J. H. Flynn B. L. Lefer F. K. Tittel Atmospheric ammonia measurements in Houston, TX using an external-cavity quantum cascade laser-based sensor Atmospheric Chemistry and Physics |
| title | Atmospheric ammonia measurements in Houston, TX using an external-cavity quantum cascade laser-based sensor |
| title_full | Atmospheric ammonia measurements in Houston, TX using an external-cavity quantum cascade laser-based sensor |
| title_fullStr | Atmospheric ammonia measurements in Houston, TX using an external-cavity quantum cascade laser-based sensor |
| title_full_unstemmed | Atmospheric ammonia measurements in Houston, TX using an external-cavity quantum cascade laser-based sensor |
| title_short | Atmospheric ammonia measurements in Houston, TX using an external-cavity quantum cascade laser-based sensor |
| title_sort | atmospheric ammonia measurements in houston tx using an external cavity quantum cascade laser based sensor |
| url | http://www.atmos-chem-phys.net/11/9721/2011/acp-11-9721-2011.pdf |
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