Fogs and air quality on the Southern California coast

Alexandra J. Boris, Denise C. Napolitano, Pierre Herckes, Andrea L. Clements, Jeffrey L. Collett

Research output: Contribution to journalArticle

2 Citations (Scopus)

Abstract

Fog acts as a reservoir and transport vector for chemicals in the atmosphere, altering the distribution of species between the gas and particle phases, and allowing deposition of nutrients and pollutants onto ecosystems and crops. Fog water and trace gas samples were collected from Casitas Pass along the Santa Barbara Channel in June 2015 to identify emissions sources and aqueous processes impacting Southern California air. Fog water composition was dominated by NH4 + (volume weighted mean, VWM = 232 µM, range = 85–640 µM), with lesser contributions from NO3 (126 µM, 30.4–778 µM) and SO4 2– (28.3 µM, 12.1–90.0 µM), pushing the VWM pH to 5.92 (5.34–6.67). Organic carbon contributed substantially to fog composition (8.27 mg C L–1, 4.70–16.8 mg C L–1). Carboxylic acids, products of aqueous oxidation, were abundant (20.1% of carbon mass on average), with > 1% contributions by acetate, formate, oxalate, malonate, succinate, and lactate. Sulfur- and nitrogen-containing organic species were detected, often after 3–5 hours of fog, suggesting aqueous formation. Sampled air was advected over the coastline near oil extraction operations, urban and agricultural areas; regional oil and natural gas processing and mobile sources were the most influential organic emissions at Casitas Pass. Fog composition in 2015 was contrasted with that from a study in July-September 1985/6. Concentrations of major fog constituents appear to have decreased in response to successful air quality regulations. While natural species concentrations in fog were similar (e.g., 2015 VWM [Na+ ] = 101 µM, range = < 30–320 µM; 1985/6 [Na+] = 129 µM, 12–1000 µM), anthropogenic species concentrations were lower in 2015 (e.g., 1985/6: [NO3 ] = 236 µM, 141–2800 µM vs. 2015: 126 µM, 30.4–778 µM). These results overall highlight changes in Southern California air quality issues, including improvement of some anthropogenic emissions and the current influence of organic emissions from industrial and mobile sources.

Original languageEnglish (US)
Pages (from-to)224-239
Number of pages16
JournalAerosol and Air Quality Research
Volume18
Issue number1
DOIs
StatePublished - Jan 1 2018

Fingerprint

Fog
fog
Air quality
Coastal zones
air quality
coast
formic acid
Oils
Gases
Chemical analysis
Oxalates
Water
air
Succinic Acid
oxalate
carboxylic acid
organic nitrogen
Carboxylic Acids
Organic carbon
Air

Keywords

  • Aqueous atmospheric chemistry
  • Aqueous secondary organic aerosol
  • Fog chemistry
  • Organic nitrogen
  • Organic sulfur

ASJC Scopus subject areas

  • Environmental Chemistry
  • Pollution

Cite this

Boris, A. J., Napolitano, D. C., Herckes, P., Clements, A. L., & Collett, J. L. (2018). Fogs and air quality on the Southern California coast. Aerosol and Air Quality Research, 18(1), 224-239. https://doi.org/10.4209/aaqr.2016.11.0522

Fogs and air quality on the Southern California coast. / Boris, Alexandra J.; Napolitano, Denise C.; Herckes, Pierre; Clements, Andrea L.; Collett, Jeffrey L.

In: Aerosol and Air Quality Research, Vol. 18, No. 1, 01.01.2018, p. 224-239.

Research output: Contribution to journalArticle

Boris, AJ, Napolitano, DC, Herckes, P, Clements, AL & Collett, JL 2018, 'Fogs and air quality on the Southern California coast', Aerosol and Air Quality Research, vol. 18, no. 1, pp. 224-239. https://doi.org/10.4209/aaqr.2016.11.0522
Boris, Alexandra J. ; Napolitano, Denise C. ; Herckes, Pierre ; Clements, Andrea L. ; Collett, Jeffrey L. / Fogs and air quality on the Southern California coast. In: Aerosol and Air Quality Research. 2018 ; Vol. 18, No. 1. pp. 224-239.
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