Refractive indices of aqueous solutions of ammonium sulfate were measu
red over a wavelength range of 240 to 400 nanometers (nm) at a tempera
ture of 292 K. The solutions examined cover a broad range from the sat
uration concentration of ammonium sulfate in water at 292 K down to lo
w concentrations. Solutions studied were: 42.5, 30.4, 23.6, 16.3, 8.5
weight per cent ammonium sulfate. Optical field measurements of these
aerosols require knowing the necessary optical constants, and these co
nstants in the ultraviolet (UV) are given here. Our results were found
to be in agreement with literature values at longer wavelengths. Addi
tionally, a Lorentz-Lorenz analysis is presented to extend our results
to other wavelengths and temperatures.