Atmospheric Aerosol Research-Nucleation

Atmospheric Field Measurements

Goals:
•To develop instrumentation for measuring size distributions of atmospheric aerosols in the nanometer diameter range
•To develop experimentally-verified models for homogeneous nucleation in the atmosphere

Locations Where Nucleation Was Observed:
•Outflow of Convective Clouds
 -High DMS, H2O, H2SO4
•On Mountains (Diurnal Profiles)
 -Mauna Loa, HI
 -Colorado Rockies
•Downwind of Macquarie Island
 -high NH3, low aerosol loadings

Conclusions About Atmospheric New Particle Formation Rates:
•Measured NPF Rates  >> Binary (H2SO4] +H2O) Theory Nucleation Rates
•Rate~[H2SO4]2, not ~[H2SO4]~10  as predicted by Binary (H2SO4] +H2O) Nucleation Theory
•NPF rates tend to be lower when preexisting aerosol surface area is high

 Publication:

Weber, R. J., J. J. Marti, P. H. McMurry, F. L. Eisele, D. J. Tanner, A. Jefferson, 1995, "Measured atmospheric new particle formation rates: Implications for nucleation theory," Chem. Eng. Comm., accepted, June, 1995

Covert, D. S., Wiedensohler, A., P. Aalto, J. Heintzenberg, P. H. McMurry, C. Leck, 1995, Aerosol number size distributions from 3 to 500 nm diameter in the Arctic marine boundary layer during summer and autumn, Tellus B, 48B:197-212.

Weber, R. J., J. J. Marti, P. H. McMurry, F. L. Eisele, D. J. Tanner, A. Jefferson, 1996, "Measured atmospheric new particle formation rates: Implications for nucleation theory," Chem. Eng. Comm., 151: 53-64.

Weber, R. J., J. J. Marti, P. H. McMurry, F. L. Eisele, D. J. Tanner, A. Jefferson, 1997, "Measurements of new particle formation and ultrafine particle growth rates at a clean continental site," J. Geophysical Res., 102 (D4) 4375-4385.

Eisele, F. L., and P. H. McMurry, 1997, Recent progress in understanding particle nucleation and growth, Philosophical Transactions, Royal Society of London, B 353:191-201

Weber, R. J., P. H. McMurry, L. Mauldin, D. J. Tanner, F. L. Eisele, F. J. Brechtel, S. M. Kreidenweis, G. L. Kok, R. D. Schillawski, D. Baumgardner, 1998, "A study of new particle formation and growth involving biogenic trace gas species measured during ACE-1," J. Geophys. Res, 103(D13):16385-16396

Wiedensohler, A., P. Aalto, D. Covert, J. Heintzenberg, P.H. McMurry 1994, "Intercomparison of four methods to determine size distributions of low concentration (~100 cm-3) ultrafine aerosols," Aerosol Sci. Technol., 21:95-109.

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