Scenario Analysis for Health Risks Associated with Hazardous Air Pollutants Emitted from Wood Pellets and Coal Burning in a Fired Power Plant

Abstract Background: Wood pellets are often promoted as a cleaner, carbon-neutral alternative to coal; however, their combustion may emit hazardous air pollutants (HAPs) with potential health impacts. Objectives: This study evaluates and compares the health risks associated with HAP emissions from wood pellet and coal combustion at a coal-fired power plant in Taichung, Taiwan. Methods: Using AERMOD for dispersion modeling and scenario-based risk analysis, we estimated lifetime cancer risk (LCR) and non-carcinogenic hazard indices (HI) via inhalation and ingestion pathways. Results: Arsenic (As) was identified as the most critical pollutant across all scenarios, with notably higher concentrations in wood pellet combustion. The ingestion-based LCR for the full wood pellet scenario exceeded the 1.0×10⁻⁶ threshold by an order of magnitude, primarily due to As accumulation in locally grown produce and livestock. Chronic non-carcinogenic risks (HI ≥1) were also elevated, affecting multiple organ systems, including cardiovascular, nervous, reproductive, and respiratory. In contrast, acute risks remained within acceptable levels (HI ≤1). Conclusions: Although wood pellets are considered cleaner than coal, our findings suggest that, without strict emission controls, they may pose equal or greater health risks. Therefore, rigorous fuel standards and risk assessments are essential prior to large-scale biomass implementation in power generation.