Fig. 1

Pathway analysis based on targeted metabolomics study. Twenty two out of the 133 metabolites were associated with internal dose of diesel exhaust exposure with FDR < 0.05. Pathway analysis identified purine metabolism as a top pathway affected by diesel exhaust exposure (FDR = 0.029). Five metabolites (i.e., IMP, inosine, hypoxanthine, adenine, and cGMP) in the purine pathway had reduced measures associated with increasing diesel exhaust exposure. Additional four pathways including cysteine and methionine metabolism, Aminoacyl-tRNA biosynthesis, Sphingolipid metabolism, and Alanine, aspartate and glutamate metabolism seemed to be affected as well though with FDRs > 0.05