Differences of chemical species and their ratios between fine and ultrafine particles in the roadside environment

Abstract

Chemical components of fine particles (FPs; aerodynamic diameter, Dp <2.5 mu m) and ultrafine particles (UFPs; Dp < 0.1 mu m) at Japanese and German roadsides were investigated during summer. The UFPs/FPs ratio for organic carbon (CC) concentrations on weekdays was 34.5% and 25.0% at Japanese and German roadsides, respectively, whereas 33% and 6.4% for elemental carbon (EC) concentrations, respectively. These results thus indicate a higher OC and a lower EC contribution from UFPs at the Japanese roadside than at the German roadside. In particle samples, OC2 and OC3 constituted a high proportion of UFPs, and pyrolyzed OC and EC1 were predominant among FPs of 0.1 mu m < Dp <2.5 mu m. Our results showed roadside environment exist not only primary FPs and UFPs but also secondary FPs and UFPs from photochemical reactions or long-range transport. (C) 2012 Elsevier Ltd. All rights reserved.