Abstract
Suspended particulate matter (SPM) in the atmosphere was collected by Andersen impactors for the past four years (April 1977-March 1981) in Kitakyushu and the amounts of heavy metals (Mn, Fe, Cu, Zn) contained in SPM were determined to investigate the atmospheric concentration of the heavy metals and its relationship with the size distribution of SPM.
The results showed little difference among seven sampling sites in mass-size distribution of SPM, where particles below 0.43μm in diameter accounted for a very large proportion of SPM mass. The mass-size distribution of SPM was also proved to be bimodal in terms of probability density function. From mass-size relationship between the heavy metals and SPM, it was found that Mn and Fe abounded in particles above 2.1 am in diameter, while Cu and Zn in particles below 2.1μm.
Sampling sites near the industrial areas were shown to have higher concentration of the heavy metals and SPM than the control site, regardless of particle size. Therefore, it is evident that places adjacent to the industrial areas are substantially subjected to particles of various sizes, which contain these metals.
SPM was classified into fine particles below 1.1μm in diameter and coarse ones above 1.1μm and the amounts of the heavy metals in the fine particles were estimated on the grounds that particles below 1.1μm in diameter are said to be small enough to be inhaled even into the lungs. The results revealed that the atmospheric concentration of the heavy metals was higher at the sites near the industrial areas than at the control site in the fine particles and the coarse ones, and that Cu and Zn were more concentrated than Mn and Fe in the fine particles. In addition, it was found that both the fine particles and the coarse ones in Kitakyushu were different from soil particles in composition.
