9528255 Lamb Atmospheric aerosol strongly affects many processes in the atmosphere, including cloud formation, chemical transformations, radiation balance, and climate. The chemical nature and microphysical behavior of these particles depend in turn on the temperature and composition of the surrounding air. The sulfuric acid particles found in the upper troposphere and lower stratosphere are very hygroscopic and tend to absorb ambient water vapor and soluble trace gases because of the low temperatures prevailing there. Detailed information on the microphysics and chemistry of aerosols can be obtained from laboratory studies. The overall objective of this research is to determine how representative aerosol particles respond to varying environmental conditions. Laboratory experiments with micron-size sulfuric acid particles levitated electrodynamically in an environmental chamber will be conducted over broad ranges of temperature and humidity in the presence of controlled concentrations of a soluble trace gas, such as nitric acid or hydrochloric acid. The experimental system, developed during prior research, is configured as a wall-less flow reactor, mimicking atmospheric conditions. Data from these experiments will yield new insights into aerosol-atmosphere interactions and serve to verify various gas-particle interaction models needed to parameterize aerosol effects in large-scale atmospheric models.
