Suspended particulate matter (SPM) concentrations were measured and their composition was analysed at many sites around The Loop Road No 8 (Traffic: 100,000 vehicle/day) to determine the source contribution to SPM in the central part of Tokyo. It was found that SPM concentrations decreased with distance from the road. SPM concentrations decreased with distance by about 20% at 100m from the road. Total SPM in winter was composed of three main components: carbons by 40%, ions by 30% and metals by 10%. The principal component analysis was performed for the data set of 16 data and 25 variables, and identified three principal components, explaining 86.4% of total variance of SPM. The first principal component, which accounts for 64.3% in the total SPM, is regarded as an overall contamination index. The most plausibly source of this component may be waste and biomass burning. The second principal component may be road dust. And the 3rd principal component may be attributable to automotive exhausted gas. (A)
Samenvatting