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List of Abstracts 90Contact: Aaron.van.Donkelaar@dal.caLong term exposure to PM 2.5 (fine aerosol with diameter < 2.5 µm) negatively affects human health, yetground-based monitoring is sparse throughout much of the world. We develop a high-resolution (0.1º x 0.1º)global climatology of PM 2.5 for 2001-2006 by combining Aerosol Optical Depth (AOD) from two satelliteinstruments (MODIS and MISR) with aerosol properties from the GEOS-Chem chemical transport model.We find significant agreement with coincident North American PM 2.5 measurements (r=0.77, slope=1.07,n=1057) and non-coincident global measurements (r=0.83, slope=0.86, n=244). Satellite-derived PM 2.5estimates over eastern North America and western Europe are between 10-20 µg/m 3 . Parts of northern Indiaand eastern China are found to have annual mean PM 2.5 concentrations of 35-60 µg/m 3 and 80-100 µg/m 3 ,respectively, with 35% of the Asian population exposure exceeding the WHO Interim Target 1 of 35 µg/m 3 .P-Observations 1.10 ID:4153 15:35Physical and chemical properties of biogenic aerosols from AmazoniaPaulo Artaxo 1 , Luciana Rizzo 1 , Kenia Wiedemann 1 , Erik Swietlicki 2 , Pontus Roldin 2 , Stefania Gilardoni 3 ,Andréa Arana 4 , Meinrat Andreae 5 , Scot Martin 6 , Alfred Wiedensohler 71 Institute of Physics, University of Sao Paulo, Brazil2 University of Lund, Lund, Sweden3 Institute for Environment and Sustainability, JRC, Ispra, Italy4 INPA – Instituto Nacional de Pesquisas da Amazônia, Manaus, Brazil5 Max Planck Institute for Chemistry, Mainz, Germany6 Harvard University, Cambridge, MA, USA7 Leibniz-Institute for Tropospheric Research, GermanyContact: artaxo@if.usp.brThe Amazon basin with more than six million square kilometers contains the world’s largest tropical rainforest, and investigations of aerosol characteristics in this large area are important for the understanding ofthe local and global influence of Amazonia on radiation budget and cloud formation. For the first time inAmazonia, a ground based long-term observations of aerosol properties were performed. The measurementswere done at the Cuieiras forest reserve, 60 km NNW of Manaus in Central Amazonia. The site is relativelyundisturbed, as the prevailing trade winds blow over vast expanses of intact tropical forest before reachingthe measurement tower. Inlet lines run from the measurement level (45m, ~10 m above tree height) to aground-based lab. A specially designed inlet allows collection of dry aerosol (20-40% RH) with a size cut of3.5 um. Several measurements are being done: optical scattering (Nephelometer TSI 3665) and absorption(Thermo MAAP 5012), size distribution (SMPS TSI, and Lund DMPS), optical particle size distribution(OPC Lasair II), total particle concentration (CPC 3010 TSI), aerosol mass (TEOM), composition (SFU)among other properties. Trace gases measurements, including O3, CO2 and CH4, were performed as well.Aerosol concentration and properties shows strong seasonal variability. For the wet season, in terms ofaerosol mass, PM2.5 is about 2.4 ug/m³, while coarse mode particles (PM10-PM2.5) is 7.5 ug/m³. Organicaerosol dominates with 70-80% of aerosol mass. In the wet season, 550 nm light scattering is very low, withan average of 4 Mm-¹. Black Carbon concentration varies from 50 to 150 ng/m³ at 550 nm. Total aerosolparticle counts varies between 100 to 300, with a peak mode in the size distribution at about 120 nm. Veryfew nucleation events were observed. The Aitken mode has been present in most of observed aerosol sizedistributions, suggesting that new particle formation may be occurring somewhere else above or below thecanopy. Aerosol volume size distributions were derived from measured number size distributions assumingspherical particles. Coarse mode particles, possibly from biogenic origin, dominate the volume size spectra,either at dry or wet season. At the dry season, PM10 aerosol mass can reach 30-50 ug/m³, with black carbonat about 400-2000 ng/m³ due to biomass burning. All parameters increase by factor of 5 to 10. Singlescattering albedo varies between 0.85 to 0.95, with lower values observed at the wet season. Coarse modeiCACGP-IGAC 2010 12 July, 2010