Humidity effect on the aerosol particle spectra in the atmospheric boundary layer

By assuming the solute to be NaCl and (NH4)2SO4, respectively, and the aerosol particle to be spherical and chemically homogeneous, the ground-based measured aerosol particle spectra are compared with those predicted based on the exact theoretical equation describing the variation of particle radius with relative humidity. This exercise is carried out for wide ranges of relative humidities from about 54–98%, and particle size ranges from about 0.1–16 μm. Comparisons show that there is reasonable agreement between predicted and measured particle spectra.