Figure 1

A. Tumor necrosis factor alpha (TNFα). and B. macrophage inflammatory protein 2 (MIP-2) (pgml^-1) after a 24-h exposure of mouse macrophage cells RAW 264.7 to emission particle (PM) samples from EURO IV engine that was run with different fuel/DOC + POC catalytic converter combinations. Bars show control level and responses to four PM doses (15, 50, 150 and 300 μg/ml) and whiskers show the standard error of the mean (SEM). Asterisks indicate statistically significant differences from the control (ANOVA and Dunnett’s test; p < 0.05). Numbers refer to a significantly larger response (ANOVA and Tukey’s test; p < 0.05) compared to the indicated other 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.