The dominant air pollutant particulates of 0.1 - 1.0 um in radius give off Mie scattering at the optical wavelength.
The distant scent of Mt. Namson (distance: 7.5Km) is photographed on the ground along the nearly horizontal path of sight. By the contrast measurement of the object, Mie scattering coefficients for three different wavelengths (6,200Å, 5,200Å, 4,000Å) are determined.
The volume concentration of the air pollutant particulates is determined from the measured Mie scattering coefficient and Junge's particle size distribution model, $n(r) = 0.434cr^{-4}$, and the validity of this model is verified in the present experiment. The volume concentration of the Seoul City obtained from this experiment is compared with those of other cities in foreign countries, and the former is found to be higher than those of the latter.
The spatial spectrum of an object is recorded on the photographic film and the change of modulus due to air pollutant particulates is measured by the coherent optical method. The change is compared with the results obtained from the contrast measurement.
