2019 Volume 54 Issue 2 Pages 55-61
The hourly optical black carbon (OBC) concentrations in PM2.5 were measured in the south (NCIES) and north (Konan) of Nagoya City in Aichi Prefecture, Japan. In the summer, the OBC concentrations were high in the daytime under the sea breeze conditions in NCIES but no strong diurnal variation for the OBC was observed in Konan. The V and Ni in the PM2.5 also showed high concentrations in the daytime in the NCIES. The source analysis of elemental carbon in the PM2.5 in NCIES using a chemical transport model (CMAQ) showed dominant contributions from automobile exhausts in the morning and from ship exhausts during the daytime. The simulated daytime OBC concentrations in NCIES were higher than those at Konan, which properly fit the observed data at the sites. According to the results of tracer elements and the model simulation, the high OBC concentration observed in the daytime in the NCIES was caused by contribution from heavy oil combustion around the bay area under the sea breeze conditions.
