1. Time Series Analysis of Satellite-Derived PM 2.5 Brian Boys, Randall V. Martin, Aaron van Donkelaar, Ryan MacDonell, Nai-Yung C. Hsu * NASA/Goddard Space Flight Ctr*

2. ~ 1 year increase of life expectancy for decreasing long-term exposure of PM 2.5 by 10 ug/m 3 Negative health outcomes from fine particulate (PM 2.5 ) exposure Increased morbidity and mortality from both acute and chronic exposure to ambient fine particulate matter (PM 2.5 )

3. Satellite-derived surface PM 2.5 : from satellite retrieved column AOD and modeled ‘surface PM 2.5 /column AOD’ ‘η’‘η’ Satellites used: MISR on TERRA, Dec 1999 - ? Designed for multianlge viewing of aerosols ~400 km swath width, ~7 day coverage SeaWiFS on SeaStar, Aug 1997 – Dec 2010 Designed to measure ocean colour ~1500 km swath width, ~2 day coverage Model used: GEOS-Chem (GC) chemical transport model * Model version 9.01.03 @ 2x2.5 deg horizontal resolution with MERRA meteorological fields www.geos.chem.org*

4. Trend [µg m -3 yr -1 ] 0 0.5 11.5 2 -0.5-1.5-2 MISR 2000 - 2011 SeaWiFS 1998 - 2010 Spatially coherent regional “trends” in satellite-derived PM 2.5

5. Trend [µg m -3 yr -1 ] 0 0.5 11.5 2 -0.5-1.5-2 MISR 2000 - 2011 SeaWiFS 1998 - 2010 Spatially coherent regional “trends” in satellite-derived PM 2.5 PM 2.5 [µg m -3 ] GEOS- Chem

6. van Donkelaar et al, in prep * JJA DJF Calipso obs. Corr. Fac. E. US Chicago η model η insitu PM 2.5 [µg m-3] / AOD Evaluation of modeled ‘PM 2.5 /column AOD’ [η] Improving modeled η with region specific Calipso correction factor *

7. GEOS-Chem, coinciently sampled with MISR 0 0.25 -0.25 1 1.5 -1.5 2 -2 0.01 0.05 0.1 P- value Trend [µg m -3 yr -1 ] Significant trends in modeled ‘PM 2.5 /column AOD’ [η] GEOS-Chem, coinciently sampled with SeaWiFS

8. 0 0.25 -0.25 1 1.5 -1.5 2 -2 0.01 0.05 0.1 MISR P- value Trend [µg m -3 yr -1 ] MISR 2000-2011 GEOS-Chem, coinciently sampled with MISR Significant trends in satellite-derived PM 2.5 : MISR

9. 0.25 1 1.5 -1.5 2 -2 0.01 0.05 0.1 SeaWiFS P- value Trend [µg m -3 yr -1 ] SeaWiFS 1998 -2010 GEOS-Chem, coincidently sampled with SeaWiFS Significant trends in satellite-derived PM 2.5 : SeaWiFS 0 -0.25

10. MISR Regional average of satellite-derived PM 2.5 : E. US trend represented by GEOS-Chem secondary inorganics (SI) fraction PM 2.5 [µg m -3 ] SeaWiFS GEOS-Chem secondary inorganics GEOS- Chem GEOS-Chem secondary inorganics GEOS- Chem

11. MISR Regional average of satellite-derived PM 2.5 : P. Gulf trend represented by GEOS-Chem fine dust fraction PM 2.5 [µg m -3 ] SeaWiFS GEOS-Chem fine dust GEOS- Chem GEOS-Chem fine dust GEOS- Chem

12. MISR Regional average of satellite-derived PM 2.5 : India trend represented by GEOS-Chem SI, OC, and BC PM 2.5 [µg m -3 ] SeaWiFS GEOS- Chem GEOS-Chem secondary inorganics GEOS-Chem BC & OC GEOS-Chem secondary inorganics GEOS-Chem BC & OC

13. MISR Regional average of satellite-derived PM 2.5 : E. Asia trend represented by GEOS-Chem SI, OC, and BC PM 2.5 [µg m -3 ] SeaWiFS GEOS- Chem GEOS-Chem secondary inorganics GEOS-Chem BC & OC GEOS- Chem

14. E. US India E. Asia PM 2.5 [µg m -3 ] MISR GC MISR GC SeaWiFS SeaWiFS Comparison of MISR and SeaWiFS: sampling effects P. Gulf MISR GC MISR GC SeaWiFS SeaWiFS MISR GC MISR GC SeaWiFS SeaWiFS MISR GC MISR GC SeaWiFS SeaWiFS PM 2.5 [µg m -3 ]

15. Conclusions Decadal(+) time series of AOD retrieving satellites Satellite-derived surface PM 2.5 concentrations show spatially coherent regional change Evolution of surface to column relationship important for satellite- derived surface PM estimates Representation of regional “trend” components through GEOS- Chem Acknowledgments