1. Long−Range Transport of Asian Sulphate to Canada Aaron van Donkelaar, Randall V. Martin, Thomas Walker – Dalhousie University W. Richard Leaitch, Anne Marie Macdonald – Environment Canada David G. Streets, Qiang Zhang – Argonne National Laboratory Edward Dunlea, Jose L. Jimenez – University of Colorado Jack E. Dibb – University of New Hampshire Greg Huey, Rodney Weber – Georgia Institute of Technology Meinrat O. Andreae – Max Plank Institute for Chemistry CAFC Meeting 31 March 2008

2. Intercontinental Chemical Transport Experiment (INTEX−B) April-May 2006 DC-8 SO 4 = (filters, mist chamber) C-130 SO 4 = (HR-ToF-AMS, PILS) Cessna SO 4 = (Q-AMS) King Air (May 1985) SO 4 = (filters) Whistler Summit SO 4 = (MOUDI)

3. Trans−Pacific Sulphate Observed at Whistler? Altitude [km] Mass Concentration [µg/m 3 ] 0 3 6 H 2 O Concentration [g H 2 O/kg] 0 1 2 3 43214321 SO 4 = Org NH 3

4. Average over April 22 - May 15 AM at Whistler (20 flights) Increasing Aerosol Size with Altitude Richard Leaitch

5. Sulphate and Calcium at Whistler Summit (2182m) Richard Leaitch

6. Simulated (GEOS-Chem) Sulphate Transport

7. Sulphate Major Component of East Asian AOD Model (GEOS-Chem) MODIS MISR MODIS MISR All Dust Model SO 4 = Model held at 2000 anthropogenic emissions GC Bias 12%MODIS 22% MISR r=0.68 r=0.60

8. Fall AOD Trend Reflects Increasing Asian SO 2 Emissions Consistent with Subsequent Bottom-up Estimate 6.2 – 9.6% emission growth per year MODIS MISR All Dust Model SO 4 = Model held at 2000 anthropogenic emissions

9. Campaign Mean SO 4 = in Free Trop Primarily Asian Lower Tropospheric Transport over Ocean, Increasing Altitude at NA Filter Pack (<4.5 um) higher than unscaled Mist Chamber (< 1um) C-130 and Cessna measurements scaled by 1.4 60-70% of SO 4 = of East Asian origin at 600 hPa Aircraft Full Emissions No East Asia Model No Anthro.

10. East Asian SO 4 = Fraction Increased by 2.4x – 3.4x Since 1985 Aircraft Full Emissions No East Asia Model No Anthro. C-130 (May 2006) King (May 1985)

11. Long−Range Transport Affects NA Sulfate Burden GEOS-Chem April-May 2006 Persistent East Asian contribution at 4 km Near Vancouver: –25-30% of surface sulfate of east Asian origin –40% of sulfate burden (1-5 km) of east Asian origin Altitude [km] SO 4 = at 2.0 km Altitude [km] % Asian SO 4 = SO 4 = [ µ g/m 3 ]

12. Conclusions Trend in East Asian AOD appears to reflect increasing SO 2 emissions 2.4-3.4x increase in the relative contribution of East Asian sulfate since 1985 Pacific basin may contain trends in aerosol-cloud feedbacks