Abstract
Particles from the Minneapolis atmosphere were segregated according to hygroscopicity using a tandem differential mobility analyzer (TDMA) and collected with a specially designed aerodynamic focusing impactor for elemental analysis. Areal deposit densities obtained using the focusing impactor are up to a factor of 100 greater than those obtained using a conventional single-jet impactor, thereby reducing required sampling times by the same factor. A Philips CM30 scanning transmission electron microscope (STEM) equipped with an EDAX super ultra-thin-window detector was used to analyze for carbon and heavier elements. For the limited sample of 0.3-0.4 μm summertime aerosols examined in this study, less hygroscopic particles included chain agglomerates (~ 55%), irregular shapes (~ 33%), spheres and flakes (< 10% each) and contained mostly carbon, while more hygroscopic particles were liquid droplets that contained sulfur and sometimes carbon or ionic species such as sodium or potassium.
Original language | English (US) |
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Pages (from-to) | 101-108 |
Number of pages | 8 |
Journal | Atmospheric Environment |
Volume | 30 |
Issue number | 1 |
DOIs | |
State | Published - 1996 |
Bibliographical note
Funding Information:Acknowledgments This research was supported by the Electric Power Research Institute (Grant No. EPRI RP2023-11) and by a U.S. DOE Graduate Fellowship for the Global Change Program (ML). Components of the aerodynamic focusing impactor were purchased with funds provided by a grant from Applied Materials.
Keywords
- Aerosol water content
- CCN
- Chemical composition
- Electron microscopy impactor
- Hygroscopic growth
- Mixing characteristics
- TDMA