Semicontinuous measurements of organic carbon and acidity during the Pittsburgh Air Quality Study: Implications for acid-catalyzed organic aerosol formation

S. Takahama, C. I. Davidson, S. N. Pandis

Research output: Contribution to journalArticlepeer-review

39 Scopus citations

Abstract

Laboratory evidence suggests that inorganic acid seed particles may increase secondary organic aerosol yields secondary organic aerosol (SOA) through heterogeneous chemistry. Additional laboratory studies, however, report that organic acidity generated in the same photochemical process by which SOA is formed may be sufficient to catalyze these heterogeneous reactions. Understanding the interaction between inorganic acidity and SOA mass is important when evaluating emission controls to meet PM2.5 regulations. We examine semicontinuous measurements of organic carbon (OC), elemental carbon (EC), and inorganic species from the Pittsburgh Air Quality Study to determine if we can detect coupling in the variations of inorganic acidity and OC. We were not able to detect significant enhancements of SOA production due to inorganic acidity in Western Pennsylvania most of the time, but its signal might have been lost in the noise. If we assume a causal relationship between inorganic acidity and OC, reductions in OC for Western Pennsylvania that might result from drastic reductions in inorganic acidity were estimated to be 2 ± 4% by a regression technique, and an upper bound for this geographic area was estimated to be 5 ± 8% based on calculations from laboratory measurements.

Original languageEnglish (US)
Pages (from-to)2191-2199
Number of pages9
JournalEnvironmental Science and Technology
Volume40
Issue number7
DOIs
StatePublished - Apr 1 2006
Externally publishedYes

ASJC Scopus subject areas

  • Chemistry(all)
  • Environmental Chemistry

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