Additional file 8: of Contrasting biological potency of particulate matter collected at sites impacted by distinct industrial sources

Cytotoxic responses of A549 cells to 24 h exposure to size-fractionated particulate matter collected in the vicinity of industrial sites according to the LDH release assay. Lactate dehydrogenase (LDH) release into cell culture supernatants of A549 cells exposed for 24 h to size-fractionated and standard reference particles (left-side) and extracts from corresponding field blank filters that were transported to each site but remained unexposed to ambient air (right side). Data represent LDH release, adjusted for total cellular LDH content. Values are presented as average fold-effect (FE) over control ± standard error (n = 3). HB, Hamilton Beach steel mill; MA, Montréal AIEM petrochemical refinery; MC, Montréal copper smelter; SR, Sarnia petrochemical refinery; SW, Shawinigan aluminum smelter. Size-fractionated and standard reference particles. Three-way ANOVA (Size-fractionated particles): Site x Size (p = 0.002) and Size x Dose (p = 0.018) interactions. Asterisks represent significant pairwise comparisons (Holm-Sidak) as follows: doses within Size significantly different from 0 μg/cm2, or sites within Size significantly different from one another as indicated by brackets (*p < 0.05, **p < 0.001). Letters (a-n) represent sizes within Site significantly different from one another (p < 0.05). Two-way ANOVA (Standards): Particle (p = 0.002) and Dose (p < 0.001) main effects. Asterisks represent significant pairwise comparisons (Holm-Sidak) as follows: doses significantly different from 0 μg/cm2, or particles significantly different from one another as indicated by brackets (*p < 0.05, **p < 0.001). Field blanks. Three-way ANOVA: Dose (p < 0.001) main effect. Letter (a) spanned by a line represents doses significantly different from 0 μg/cm2 (p < 0.001). (PDF 55 kb