The particle size distributions of dechloranes were determined. For collecting PM, an Andersen air sampler equipped with five-stage quartz fiber filters and a PM0.1 air sampler equipped with six-stage Teflon and inertial SUS fiber filters were used. Particulate matter (PM) was collected in April 2014 by Andersen air sampler and October 2014 and January 2015 by PM0.1 air sampler. The samples were analyzed for Dechlorane Plus (DP), Dechlorane602, Dechlorane603, and Dechlorane604 Component A using gas chromatography high-resolution mass spectrometry. The almost all nanoparticles smaller than 100 nm are reported to reach and deposit in lung periphery, so it is important to reveal the concentration of these dechloranes in nanoparticles. In our study, only DP was detected in PM. DP was detected from all the filter samples. In this study, the particle size distribution of DP was revealed for the first time and the approximately 70 ％ of DP exist in ＜2.5 µm fractions and 10 ％ of DP exist in ＜0.1 µm fractions of PM samples.
