Atmospheric transport of acidity in southern California by wet and dry mechanisms
Acid precipitation samples collected at Pasadena, California, from February 1976 to April 1979 and at eight other southern California sites for shorter periods were analyzed to determine acid and base composition. The concentrations of major cations (H+, NH4+, Na+, K+, Ca2+, Mg2+) and anions (Cl-, N...
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ftdatacite:10.7907/pgev-yh86 2023-05-15T15:53:03+02:00 Atmospheric transport of acidity in southern California by wet and dry mechanisms Liljestrand, Howard Michael 1980 PDF https://dx.doi.org/10.7907/pgev-yh86 https://resolver.caltech.edu/CaltechETD:etd-10102006-110816 en eng California Institute of Technology No commercial reproduction, distribution, display or performance rights in this work are provided. Atmospheric transport of acidity Environmental Science and Engineering Thesis Text Dissertation thesis 1980 ftdatacite https://doi.org/10.7907/pgev-yh86 2021-11-05T12:55:41Z Acid precipitation samples collected at Pasadena, California, from February 1976 to April 1979 and at eight other southern California sites for shorter periods were analyzed to determine acid and base composition. The concentrations of major cations (H+, NH4+, Na+, K+, Ca2+, Mg2+) and anions (Cl-, NO2-, Br-, NO3-, SO42) as well as trace weak acids (Fe, Al, Mn, Si(OH)4, RCOOH) were determined. Titrations with base showed acidity predominantly to be due to strong acids (nitric and sulfuric) and weak acids (ammonium ion and carbonic acid). The pH was controlled by strong acidity at the urban sites in the Los Angeles Basin. The chemical composition of precipitation samples collected in ~0.25 in increments is modeled in several ways. Chemical balances are used to determine the contributions of sea salt, soil dust, stationary sources, mobile sources and non-point sources of ammonia. Multiple regression analysis is used to relate ground-level measurements of air quality and atmospheric conditions with rainwater nitrite plus nitrate and sulfate concentrations. Precipitation intensity, ozone, nitric oxide and nitrogen dioxide concentrations are most strongly correlated with rainwater nitrite plus nitrate. Precipitation intensity, ozone, and nitric oxide are most strongly correlated with rainwater sulfate. Gas-liquid equilibrium models yield the following predictions: Low partial pressures of ammonia (average of 0.001 - 0.006 ppbv within the basin) during precipitation scavenging; total sulfite amounting to less than 25% of the non-sea salt sulfur; and nitrite concentrations from NO and NO2 dissolution which are slightly larger than observed values. Kinetic models of the formation of nitrate and sulfate underestimate the observed concentrations. Spatial distributions of acids and base correspond with local sources. The mountain sites and the more rural eastern sites have significantly less net acidity than the western urban sites. Estimates of the dry deposition of atmospheric acids indicate the dry flux is ~6600 equivalents/HA-YR in the Los Angeles Basin compared to ~380 equivalents/HA-YR for the wet flux of strong acidity. The semi-arid climate and high ambient pollutant concentrations cause the large dry flux. Advection of pollutants is the most important mechanism for the removal of acidity from the Los Angeles airshed. Thesis Carbonic acid DataCite Metadata Store (German National Library of Science and Technology) |
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Atmospheric transport of acidity Environmental Science and Engineering |
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Atmospheric transport of acidity Environmental Science and Engineering Liljestrand, Howard Michael Atmospheric transport of acidity in southern California by wet and dry mechanisms |
topic_facet |
Atmospheric transport of acidity Environmental Science and Engineering |
description |
Acid precipitation samples collected at Pasadena, California, from February 1976 to April 1979 and at eight other southern California sites for shorter periods were analyzed to determine acid and base composition. The concentrations of major cations (H+, NH4+, Na+, K+, Ca2+, Mg2+) and anions (Cl-, NO2-, Br-, NO3-, SO42) as well as trace weak acids (Fe, Al, Mn, Si(OH)4, RCOOH) were determined. Titrations with base showed acidity predominantly to be due to strong acids (nitric and sulfuric) and weak acids (ammonium ion and carbonic acid). The pH was controlled by strong acidity at the urban sites in the Los Angeles Basin. The chemical composition of precipitation samples collected in ~0.25 in increments is modeled in several ways. Chemical balances are used to determine the contributions of sea salt, soil dust, stationary sources, mobile sources and non-point sources of ammonia. Multiple regression analysis is used to relate ground-level measurements of air quality and atmospheric conditions with rainwater nitrite plus nitrate and sulfate concentrations. Precipitation intensity, ozone, nitric oxide and nitrogen dioxide concentrations are most strongly correlated with rainwater nitrite plus nitrate. Precipitation intensity, ozone, and nitric oxide are most strongly correlated with rainwater sulfate. Gas-liquid equilibrium models yield the following predictions: Low partial pressures of ammonia (average of 0.001 - 0.006 ppbv within the basin) during precipitation scavenging; total sulfite amounting to less than 25% of the non-sea salt sulfur; and nitrite concentrations from NO and NO2 dissolution which are slightly larger than observed values. Kinetic models of the formation of nitrate and sulfate underestimate the observed concentrations. Spatial distributions of acids and base correspond with local sources. The mountain sites and the more rural eastern sites have significantly less net acidity than the western urban sites. Estimates of the dry deposition of atmospheric acids indicate the dry flux is ~6600 equivalents/HA-YR in the Los Angeles Basin compared to ~380 equivalents/HA-YR for the wet flux of strong acidity. The semi-arid climate and high ambient pollutant concentrations cause the large dry flux. Advection of pollutants is the most important mechanism for the removal of acidity from the Los Angeles airshed. |
format |
Thesis |
author |
Liljestrand, Howard Michael |
author_facet |
Liljestrand, Howard Michael |
author_sort |
Liljestrand, Howard Michael |
title |
Atmospheric transport of acidity in southern California by wet and dry mechanisms |
title_short |
Atmospheric transport of acidity in southern California by wet and dry mechanisms |
title_full |
Atmospheric transport of acidity in southern California by wet and dry mechanisms |
title_fullStr |
Atmospheric transport of acidity in southern California by wet and dry mechanisms |
title_full_unstemmed |
Atmospheric transport of acidity in southern California by wet and dry mechanisms |
title_sort |
atmospheric transport of acidity in southern california by wet and dry mechanisms |
publisher |
California Institute of Technology |
publishDate |
1980 |
url |
https://dx.doi.org/10.7907/pgev-yh86 https://resolver.caltech.edu/CaltechETD:etd-10102006-110816 |
genre |
Carbonic acid |
genre_facet |
Carbonic acid |
op_rights |
No commercial reproduction, distribution, display or performance rights in this work are provided. |
op_doi |
https://doi.org/10.7907/pgev-yh86 |
_version_ |
1766388119833149440 |