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Frank Flocke, Aaron Swanson, Jim Roberts, Greg Huey, David Tanner Tom Ryerson, Andy Neuman ,

Fast time resolution airborne measurements of PANs during the New England Air Quality Study 2004 intensive. Frank Flocke, Aaron Swanson, Jim Roberts, Greg Huey, David Tanner Tom Ryerson, Andy Neuman , John Holloway, Joost deGouw, Carsten Warneke

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Frank Flocke, Aaron Swanson, Jim Roberts, Greg Huey, David Tanner Tom Ryerson, Andy Neuman ,

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  1. Fast time resolution airborne measurements of PANs during the New England Air Quality Study 2004 intensive. Frank Flocke, Aaron Swanson, Jim Roberts, Greg Huey, David Tanner Tom Ryerson, Andy Neuman, John Holloway, Joost deGouw, Carsten Warneke Elliot Atlas, Stephen Donnelly, Sue Schauffler, Verity Stroud Thanks to: NOAA AOC, Paul Stock (DLR)

  2. New PAN-CIGAR instrument: • Chemical Ionization Mass Spectrometer • Based on reaction of PA radicals with I- • Fast (time resolution 0.25 – 2 seconds) • Sensitive (10-60 cts/pptv on background of 250 cts or less) • Very selective • Autonomous • Eight different PAN species measured during ICARTT 2004 • don’t miss the PAN-CIGAR Instrument talk: Swanson et al., A42B-04; Thu, 11:20; MCC 3018 Tropospheric Photochemistry II

  3. Which PANs were measured?Example flight 7/20/2004, NYC plume

  4. Biomass burning plume encountered over Quebec 7/28/2004 Flight alt. 3000m Flight alt. const. 3000m

  5. Biomass burning plume encountered over Quebec 7/28/2004 Flight Alt. const. 3000m Flight alt. 3000m

  6. PAN transport and NOx release

  7. 7/20/2004 Biomass burning plume from AK and CDN Fires PAN is dominant NOY component, HNO3 washed out or lost on aerosols, PAN decomposition maintains NOX on air mass descent τ(PAN) ≈ 20h

  8. 7/21/2004 Same biomass burning plume from AK and CDN Fires encountered again over Cape Cod one day later Some processing has occurred (HNO3 formation), still PAN decomposition maintains NOX on air mass descent τ(PAN) ≈ 18h

  9. Biomass Burning during ICARTT don’t miss Joost de Gouw, A51G-05; Fri, 9:15, MCC 3018 Tropospheric Photochemistry VI

  10. PAN / PPN ratio

  11. What controls the PAN / PPN ratio: Production:-PAN / PPN ratio upon formation depends on availability of source VOC -Alkanes/Alkenes make PAN and PPN (ratio?) -Isoprene and Terpenes make just PAN  PAN/PPN increases with biogenic HC burden More PAN further away from sources (?) and loss: warm PBL: -Thermal loss is fastest -PAN is lost faster than PPN (Kirchner et al., 2000)  PAN / PPN decreases (hours-days) Upper Troposphere: -Photolysis dominates -PPN photolysis slightly faster than PAN (Harwood et al., 2003)  PAN / PPN increases very slowly (weeks)

  12. PAN / PPN ratio: Is there an “anthropogenic” PAN/PPN ratio?

  13. Slope ~ 6 PAN/PPN during TRACE-P Similar slopes of PAN / PPN were obtained in Houston (TexAQS 2000), during TOPSE (Spring 2000) and in/over other urban areas

  14. PAN / PPN ratio: and in New England?

  15. Slope~12 Slope~9 Slope~6 7/20/2004 flight

  16. 7/31/2004 Flt, NYC Plume at Night Biogenic influence reflected in PAN/PPN ratio

  17. PAN / PPN ratio: Can we see the effect of different thermal loss rates?

  18. Flight 8/10/2004 – NYC Plume at Night

  19. Flight 8/10/2004 – NYC Plume at Night

  20. Flight 8/10/2004 – NYC Plume at Night

  21. Flight 8/10/2004 – NYC Plume at Night

  22. SUMMARY • First fast time resolution airborne measurements of PAN • We observed 8 different PANs including • first observations of MoPAN, PPeN (and PBzN) • Elevated APAN and MoPAN in biomass burning plumes • One can learn a lot about photochemical history of air masses by just measuring PAN and PPN accurately • We can do that now at 2 Hz or better • Biomass burning plumes show distinct PAN/PPN ratio which appears preserved over several days

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