Figure 2

A. Cell death assessed with the MTT test after a 24-h exposure of RAW 264.7 macrophages to emission PM samples from EURO IV engine run with different fuel/DOC   + POC catalytic converter combinations. Bars represent control level and responses to four PM doses (15, 50, 150 and 300μgml^-1) and whiskers show the standard error of the mean (SEM). Asterisks indicate statistical significant differences from the control (ANOVA and Dunnett’s test; p < 0.05). B. Cell death (mostly necrosis) detected with PI-exclusion method in the same exposure of RAW 264.7 cells as in panel A. Asterisks indicate statistically significant differences from the control level (Kruskall-Wallis; p < 0.05). Numbers refer to a significantly larger MTT-test response (ANOVA and Tukey’s test; p < 0.05) or PI-exclusion test response (Dunnett’s C test; p < 0.05) compared to the indicated fuel/catalytic converter combination: 1) EN590, 2) EN590 + cat, 3) 30% HVO, 4) 100% HVO, 5) HVO + cat 6) 30% RME, 7) 100% RME, and 8) CNG bus.