TY - JOUR
T1 - Unique isoprene oxidation products demonstrate chlorine atom chemistry occurs in the Houston, Texas urban area
AU - Riemer, Daniel D.
AU - Apel, Eric C.
AU - Orlando, John J.
AU - Tyndall, Geoffrey S.
AU - Brune, William H.
AU - Williams, Eric J.
AU - Lonneman, William A.
AU - Neece, James D.
N1 - Funding Information:
Acknowledgements D. Riemer gratefully acknowledges project support from the former Texas Natural Resource Conservation Commission (TNRCC), now known as the Texas Commission on Environmental Quality (TCEQ). He also appreciates the substantial early support provided by the NSF sponsored NCAR - Advanced Study Program. Dr. Elliot Atlas provided assistance with the GC/AED analyses. We acknowledge the helpful suggestions by two anonymous reviewers.
PY - 2008
Y1 - 2008
N2 - 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 5-70-30 atoms cm-3. Cl concentration during all the episodes averaged 7.6-2.0-4.7 x104 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.
AB - 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 5-70-30 atoms cm-3. Cl concentration during all the episodes averaged 7.6-2.0-4.7 x104 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.
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U2 - 10.1007/s10874-009-9134-5
DO - 10.1007/s10874-009-9134-5
M3 - Article
AN - SCOPUS:77149177663
SN - 0167-7764
VL - 61
SP - 227
EP - 242
JO - Journal of Atmospheric Chemistry
JF - Journal of Atmospheric Chemistry
IS - 3
ER -