Additional file 7: 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 resazurin reduction assay. Metabolic reduction of non-fluorescent resazurin in 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). Values are presented as average fold-effect (FE) over control ± standard error (n = 3 independent experiments). 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 < 0.001) and Size x Dose (p = 0.019) interactions. Asterisks represent significant pairwise comparisons (Holm-Sidak) as follows: doses within Site 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-h) represent sizes within Site significantly different from one another (p < 0.05). Two-way ANOVA (Standards): Particle x Dose interaction (p = 0.012). Asterisks represent significant pairwise comparisons (Holm-Sidak) as follows: doses within Particles significantly different from 0 μg/cm2 (**p < 0.001). Letters (a,b) represent sites within Dose significantly different from one another (p < 0.5). Field blanks. Three-way ANOVA: Site x Size (p < 0.001) interaction. Asterisks represent significant pairwise comparisons (Holm-Sidak) as follows: sites within Size significantly different from one another as indicated by brackets (*p < 0.05, **p < 0.001). Letters (a-e) represent sizes within Site significantly different from one another (p < 0.05). (PDF 54 kb