Fig. 4
Comparison of road tunnel PM to stone particles and diesel exhaust particles (DEP) on cytokine release in HBEC3-KT cells. The cells were exposed to 100 µg/mL (10.4 µg/cm2) of coarse (C), fine (F) and ultrafine (UF) PM sampled in the Marienborg (white bars) and Hell (grey bars) tunnels for 20 h, and compared to the same concentrations (100 µg/mL (10.4 µg/cm2)) of particles from the stone materials rhomb porphyry (RP) and quartz diorite (QD) used in the respective tunnels (a and c, black bars) or to diesel exhaust particles (DEP) (b and d, black bars). Release of IL-1α (a, b) and CXCL8 (c, d) was analysed by ELISA. Results are presented as mean ± SEM of 7 independent experiments. *Significant different from control. Brackets, significantly different from the different sizes of road tunnel PM. The statistical analysis was performed by one-way ANOVA with Dunnett’s multiple comparison test