Journal of Atmospheric Chemistry

, Volume 61, Issue 3, pp 227–242

Unique isoprene oxidation products demonstrate chlorine atom chemistry occurs in the Houston, Texas urban area

  • Daniel D. Riemer
  • Eric C. Apel
  • John J. Orlando
  • Geoffrey S. Tyndall
  • William H. Brune
  • Eric J. Williams
  • William A. Lonneman
  • James D. Neece
Article

DOI: 10.1007/s10874-009-9134-5

Cite this article as:
Riemer, D.D., Apel, E.C., Orlando, J.J. et al. J Atmos Chem (2008) 61: 227. doi:10.1007/s10874-009-9134-5

Abstract

As part of the 2000 Texas Air Quality Study (TexAQS), we studied the isoprene oxidation process under ambient conditions to discern the presence of chlorine atom (Cl) chemistry in the Houston, Texas urban area. By measuring chloromethylbutenone (CMBO) and an isomer of chloromethylbutenal (CMBA), we clearly observed sixteen episodes of active Cl chemistry during the 24-day experiment. Estimated median Cl concentration during each of these episodes was between the detection limit of ~102 atoms cm−3 and \( 50_{ - 30}^{ + 70} \times {10^4} \) atoms cm−3. Cl concentration during all the episodes averaged \( 7.6_{ - 2.0}^{ + 4.7} \times {10^4} \) atoms cm−3 and thus amounted to less than 3% of the OH concentration during the same periods. During the episodes, the fraction of oxidation chemistry initiated by Cl ranged from 3–43% and was strongly dependent on the quantity and type of hydrocarbons present in the atmosphere. Because of its intermittent presence and low concentration, Cl is not a broadly influential oxidant in the Houston, Texas urban area.

Keywords

Chlorine atoms Chloromethylbutenal Chloromethylbutenone Isoprene Ozone Urban air quality 

Copyright information

© © US Government 2009 2009

Authors and Affiliations

  • Daniel D. Riemer
    • 1
  • Eric C. Apel
    • 2
  • John J. Orlando
    • 2
  • Geoffrey S. Tyndall
    • 2
  • William H. Brune
    • 3
  • Eric J. Williams
    • 4
  • William A. Lonneman
    • 5
  • James D. Neece
    • 6
  1. 1.University of Miami, RSMAS/MACMiamiUSA
  2. 2.National Center for Atmospheric ResearchBoulderUSA
  3. 3.Department of MeteorologyPennsylvania State UniversityUniversity ParkUSA
  4. 4.NOAA Earth System Research LaboratoryBoulderUSA
  5. 5.U. S. Environmental Protection Agency, SEE ProgramResearch Triangle ParkUSA
  6. 6.Texas Commission on Environmental QualityAustinUSA

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