Urinary Amino-Polycyclic Aromatic Hydrocarbons in Urban Residents: Finding a Biomarker for Residential Exposure to Diesel Traffic
Zhenchun Yang, Yan Lin, Stella Wang, Xing Liu, Paul Cullinan, Kian Fan Chung, Junfeng Zhang
Abstract
Despite substantial evidence of marked exposure to and ill-health effects from diesel exhaust (DE) emissions among occupational population (e.g., miners, truck drivers, and taxi drivers), it is less understood to what extent non-occupational population was exposed to DE among various combustion sources, largely due to the lack of biomarkers that would indicate specific exposure to DE. We evaluated whether urinary amino-polycyclic aromatic hydrocarbons (APAHs), such as major metabolites of DE-specific nitrated PAHs, can be used as DE exposure biomarkers in residential settings. We measured five urinary APAHs in 177 urine samples from 98 UK residents, 89 (91%) of them were London residents, and estimated their residential proximity to various traffic indicators (e.g., the road type, road length, traffic flow, and traffic volume). Participants living within 100 m of major roads exhibited increased levels of all five APAHs, among which 2-amino-fluorene (2-AFLU) reached statistical significance (p < 0.05). We estimated that a 10 m increase in the length of nearby major roads (<100 m) was associated with a 4.4% (95% CI of 1.1 to 7.6%) increase in 2-AFLU levels. Levels of 2-AFLU were significantly associated with the traffic flow of nearby buses and heavy-duty vehicles but not motorbikes, taxis, or coaches. We did not observe a significant association between distance to major roads or the sum of the major road length within 100 m with the other four biomarker concentrations. These results suggest the use of urinary 2-AFLU as a biomarker of DE exposure in urban residents.