Dioxin Concentration of Particulate and Gaseous Substances in the Ambient Air by Particle Size — Comparison between Specimens Collected in Summer and in Winter at Tokyo

Size-fractionated air-borne particles and gaseous samples were collected using Andersen low pressure impactor with polyurethane foam at Tokyo. Dioxin concentrations of these particles and gaseous substances were measured with high resolution gas chromatograph/high resolution mass spectrometer (HRGC/HRMS). Particle diameter distribution has two peaks, one around 0.7 μm and the other around 5 μm both in summer and winter. But, dioxin has a peak at around the particle diameter of 0.52 μm. And, It was observed that smaller particle was the higher weight concentration of dioxins in the particle except in the case of tetrachlorodibenzofurans (TeCDFs). From these results, it was recognized that 75% or more of toxic dioxin component was contained in particles of 1 μm or smaller.