1. Chemically, Size, and Time-Resolved Hydration of Field-Aerosols via Single Particle ESEM/EDX Alex Laskin, Martin Iedema, James Cowin Pacific Northwest National Laboratory Richland, Washington

2. Differential mobility analyzers have for years now provided valuable SIZE resolved data on hydrscopic nature of particles. Now we can add Chemically Resolved (without DMA)

3. Aerosol Morphology and Hydration Properties Studied Using Environmental Scanning Electron Microscopy sample Pump Gases detector Pressure: 2 to 20 Torr The ESEM operates at atmospherically relevant humiditiess and temperatures. Enables studies of the morphology and composition) of aerosols with nanometer resolution. Fully Automated Studies of Hydration an reactivity.

4. Depth profiling Depth profiling of particles sulfate/nitrate coating carbonaceous core

5. Houston 2000 Particles: Movie showing hydration vs humidity

6. Pacific NW 2001 Study: Semivolatile organic particles (left cntr)

7. Basic Mechanisms Collaborations (with lots of on site work at PNNL) with: Vicki Grassian, (U. Iowa) Mineral Particle Reactions Barney Ellison (U. Col.) Organics converting to hydrophilic compounds on aqueous, mineral particles

8. Conclusion Directly Measure Hydroscopic Properties of Field- Collected Aerosols Chemically, Size, Time (optional) resolved Collectors are fairly cheap, small. Effect of Surface Films can be detected, probed