Abstract
In an urban environment, visibility strongly reflects human safety and welfare. Generally, visibility is dependent on particle
scattering and absorption. The former is influenced by light wavelength, atmospheric gaseous species and particle characteristics,
especially number and size distribution. Therefore, it is necessary to establish the relationship between visibility and particle
characteristics. Furthermore, it is important to understand the formation mechanism of secondary aerosols. In this study, a microorifice uniform deposit impactor (MOUDI) was used to measure the particle size distribution. At the same time, the particle
scattering coefficient was measured with a nephelometer. After sampling, the chemical compositions of the particulates were
analyzed via ion chromatography (IC) and a total organic carbon (TOC) analyzer. The results show that coarse particulates are
not related to the scattering coefficient, whereas the scattering coefficient is slightly relative to the fine particle mass
concentration. From the measured scattering coefficient, the visibility was calculated to be in the range of 20,000 to 120,000 m.
The predicted visibility is greater than the observed data, ranging from 18,000 to 100,000 m at the Song-Sun Airport.