2006 Graduate Student Symposium Measurement of HCl (g) in troposphere and lower stratosphere with CIMS technique Analytical characteristics and its implications of Atmospheric Cl Chemistry Saewung Kim

2006 Graduate Student Symposium Introduction – Cl Chemistry in Atmosphere Troposphere Importance of Cl chemistry has been recognized in stratosphere and troposphere (mostly marine boundary layer). Stratosphere

Introduction – Cl Chemistry in Stratosphere Troposphere ♣ Stratospheric Cl Radical Chemistry -Cl catalyzed Ozone layer destruction (Stolarski & Cicerone 1974) 2006 Graduate Student Symposium Cl + O 3  ClO + O 2 ClO + O  Cl + O 2 O 3 + hv  O + O 2 Net 2O 3  3O 2 Where is Cl coming from? Stratosphere

2006 Graduate Student Symposium Introduction – Cl Chemistry in Stratosphere Troposphere (UV is not available) CFCl 3 CF 2 Cl 2 ClClO HOCl ClONO 2 HCl Stable in Trop. Photolysis in Strato. Molina & Rowland,1974 Stratosphere (UV available) hv O3O3 O, NO HO 2 OH NO 2 hv CH 4 OH ♣ HCl(g) in Stratosphere - relative long life time(~weeks) reservoir species of active Cl (=Cl + ClO). - Good tracer for stratospheric influence in troposphere SUN

2006 Graduate Student Symposium Introduction – Cl Chemistry in Marine Boundary Layer Ocean ♣ Ocean Boundary Layer - Gas phase reactive Cl and HCl are formed by heterogeneous reaction either NaCl(aq) or NaCl(s) - Fast oxidation process of VOC by Cl (~250 times faster than OH oxidation for ethane) sometimes can make significant ozone production rate especially polluted marine boundary layer NaCl(s) NaCl(aq) ClNO(g) NO 2 ClR RO2 O 3 Production HCl hv HNO 3 OH  = 3 days Washout Heterogeneous Rxn.

2006 Graduate Student Symposium INTEX (Intercontinental Chemical Transport Experiment) –B, Spring 2006 Anchorage Houston Honolulu Flying from Boundary layer upto lower stratosphere(0 - 12km) HCl was measured during Anchorage deployment over remote ocean

2006 Graduate Student Symposium CIMS (Chemical Ionization Mass Spectromentry) for HCl HCl 34 SO 2 SF 5 Cl - F 2 34 SO 2 - SF 6 - SF Po Ambient air Charcoal Scrubber Temp. Cont. Inlet (25 o C) 34 SO 2 STD. Addition Ion Reactor HCl and 34 SO 2 (Flight Standard) react with SF 6 - ion and produce selective product ions Ion Optics CDC, Octopole Decluster Ion and focus ion beam Mass Filter and Det. The Ion is selected by quadruple mass filter and detected by channeltron ♣ Performance of System Uncertainty : 33% (2σ, 1sec) Limit of Detection : 2pptv (2σ, 30sec) ♣ Previous study Filter method : contamination issue CIMS with SF 5 - Ion Chem. : High Alt. Only (Marcy et al, 2004)

2006 Graduate Student Symposium Vertical Profile of HCl over Remote North Pacific UTLS(8-12km) Mid-Trop (boundary layer – 8 km) Marine Boundary Layer - UTLS shows highest HCl from stratospheric influence and Marine Boundary layer shows enhanced HCl (~ 30pptv) HCl (pptv) - Keene et al., 1999 calculated HCl budget of global troposphere with above profiles referred from past measurement of HCl over remote ocean environment. They reported huge deficit of source of HCl. ~ 5-10 times higher than what we measured Keene et al HCl profile over Remote Ocean

2006 Graduate Student Symposium HCl in UTLS (upper troposphere and Lower Stratosphere km) -HCl shows strongest correlation with O3 among the tracers used for stratosphere air mass (HNO 3, CO and water vapor)  HCl can serve good tracer for stratospheric air Great Correlation with O3! No Background! - These data can serve for constraint of stratospheric chemistry model. (Z = 8 – 12 km)

2006 Graduate Student Symposium HCl in Remote mid troposphere (4-8 km) ♣ two Spiral profiles Spiral 1 : Air-mass in mid trop was originated from remote N-Pacific Spiral 2 : Air-mass in mid trop was originated from Asian region Spiral 1 Spiral 2

2006 Graduate Student Symposium HCl in Remote Mid -Troposphere (4-8 km) ♣ Cl chemistry of mid troposphere have not been investigated. This case study suggest that Cl chemistry can be activated when pollution transport into mid troposphere. Enhancement from Asian pollution Where does Enhanced HCl come from in spiral 2 Stratosphere? No O 3,High CO, High H 2 O(g) - Negative Marine Boundary Layer? Low CH 3 I, CH 3 NO 3 - Negative

2006 Graduate Student Symposium Summary Ocean Tropopause 1. CIMS with SF 6 - ion chemistry SUCESSFULLY MEASURE HCl in trace level from boundary layer up to 12km 3. HCl is unique tracer for stratospheric influence (no background & great correlation with stratospheric O 3 ) and stratosphere data are expected to be good constraint for model study 2. Our preliminary data suggest previous HCl data of remote marine region seems overestimated 4. Case study suggest pollution layer could trigger Cl chemistry remote mid troposphere region Boundary Layer Stratosphere

2006 Graduate Student Symposium Acknowledgements O 3 : Dr. Melody Avery NASA Langley Research Center HNO3 : Dr Jack Dibb U of New Hempshire Aerosol : Prof. Anthony Clarke U of Hawaii Committee of GSS

2006 Graduate Student Symposium HCl in Marine Boundary Layer -The strong correlation with HNO 3 reflects remote ocean boundary layer is HNO 3 limiting environment for HCl production. HCl NaCl (aq)VOC DepostionCl (Z = 0 – 1 km) HNO 3 Cl Precipitation Aerosol OH