Fig. 1
Cytokine release and cytotoxicity in HBEC3-KT cells after exposure to size-fractionated road tunnel PM. The cells were exposed to coarse (C: PM10–2.5), fine (F: PM2.5–0.18) and ultrafine (UF: PM0.18) PM sampled in the Marienborg (white bars) and Hell (grey bars) tunnels at a concentration of 100 µg/mL (10.4 µg/cm2) for 20 h. Release of IL-1α (a), IL-1β (b), CXCL8 (c) in the cell culture supernatant was analysed by ELISA, and cytotoxicity was measured by lactate dehydrogenase (LDH) release (d). Data are presented as mean ± SEM of 3–19 independent experiments. *Significant increase compared to control. Brackets, significantly difference between different sizes of road tunnel PM. ¤Significantly different between tunnels at the same PM size. The statistical analysis was performed by 2-way ANOVA with Tukey’s multiple comparison test or Sidak’s multiple comparison test