The Influence of Traffic-Related Air Pollution (TRAP) in Primary Schools and Residential Proximity to Traffic Sources on Histone H3 Level in Selected Malaysian Children

This study aimed to investigate the association between traffic-related air pollution (TRAP) exposure and histone H3 modification among school children in high-traffic (HT) and low-traffic (LT) areas in Malaysia. Respondents’ background information and personal exposure to traffic sources were obtained from questionnaires distributed to randomly selected school children. Real-time monitoring instruments were used for 6-h measurements of PM(10), PM(2.5), PM(1), NO(2), SO(2), O(3), CO, and total volatile organic compounds (TVOC). Meanwhile, 24-h measurements of PM(2.5)-bound black carbon (BC) were performed using air sampling pumps. The salivary histone H3 level was captured using an enzyme-linked immunosorbent assay (ELISA). HT schools had significantly higher PM(10), PM(2.5), PM(1), BC, NO(2), SO(2), O(3), CO, and TVOC than LT schools, all at p < 0.001. Children in the HT area were more likely to get higher histone H3 levels (z = −5.13). There were positive weak correlations between histone H3 level and concentrations of NO(2) (r = 0.37), CO (r = 0.36), PM(1) (r = 0.35), PM(2.5) (r = 0.34), SO(2) (r = 0.34), PM(10) (r = 0.33), O(3) (r = 0.33), TVOC (r = 0.25), and BC (r = 0.19). Overall, this study proposes the possible role of histone H3 modification in interpreting the effects of TRAP exposure via non-genotoxic mechanisms.