Assessment of traffic-related PAH in various environmental components and its associated health risk at a highway Toll Plaza

Abstract

Introduction: This study investigated Polycyclic Aromatic Hydrocarbon (PAH) emissions from road traffic at the Surathkal toll plaza, in Karnataka, India. It focuses on two phases: when the toll station operated (Phase 1: January 2020 – March 2020) and when it was inactive (Phase 2: January 2023 – March 2023). Materials and methods: The research examines Suspended Particulate Matter (SPM) concentration, its elemental analysis, and various PAH concentrations in it during both phases. Ultrasonic extraction and Gas Chromatography (GC) analysis were used to study 16 priority PAHs recommended by the United States Environmental Protection Agency (US-EPA), identifying eight in samples like SPM, soot, and green leaves. Inductively Coupled Plasma Optical Emission Spectrophotometer (ICPOES) analysed 14 elements in SPM. Results: Results revealed higher PAH concentration during Phase 2, indicating that the presence of toll structure negatively affects air quality even when inactive. In contrast, SPM and its elements had higher mean concentrations during Phase 1, suggesting an inverse relationship between SPM and PAH levels. PAH diagnostic ratios showed different sources for each phase, including gasoline, diesel, fossil fuel, coal/biomass, and pyrogenic sources. Comprehensive health risk assessment using BaP equivalent concentration (BaPeq) to estimate Inhalation Life-time Cancer Risk (ILCR), revealed an increased risk during both phases (0.045 during Phase 1 and 0.134 during Phase 2), higher than acceptable risk level (1×10-6). Conclusion: This research underscores the toll plaza's significant influence on air quality and calls for the development of mitigation measures.

Keywords

• Polycyclic aromatic hydrocarbon (PAH); Toll structure; Soot; Suspended particulate matter; Green plants