A chamber for laboratory studies of atmospheric aerosols and clouds

Abstract

A stainless-steel chamber has been constructed and interfaced to a Fourier transform infrared spectrometer for the purpose of studying laboratory simulated atmospheric aerosols and clouds. The chamber is cylindrical in design and is comprised of a double-walled inner assembly that resides within an outer vacuum jacket. The volume of the aerosol sample region is 28 L. By circulating refrigerated methanol between the double walls of the inner assembly, constant temperature control of the sample region can be maintained between 187 and 300 K. A study of temperature uniformity within the chamber at 291, 240, and 187 K revealed a standard deviation in temperature of 1.6 K as determined from measurements made using five copper-constantan thermocouples. Good agreement is obtained between thermocouple measured temperatures and rotational temperatures computed from infrared absorption spectra of methane gas. The chamber described here has been used to examine heterogeneous chemistry of solid powder samples. A technique of generating an aerosol sample by rapidly dispersing a solid powder in a gas is presented. The half-life of a γ-alumina aerosol sample was measured to be 25 min. © 1996 American Institute of Physics.