Jianpeng Li, Wenfang Liu, Zhihua Liu
Abstract Accurate stationary source emission monitoring is currently compromised by two critical metrological limitations: the fragmentation of traceability chains for flow velocity versus particulate matter (PM), and the deficiency of conventional facilities in reproducing the complex thermodynamics of wet flue gas. To bridge these gaps, we developed the Integrated Dual-Function Wind Tunnel (IDFWT), utilizing a novel “tandem test-section” architecture to establish a unified traceability framework. This system uniquely generates both a U.S. EPA-compliant low-turbulence flow for aerodynamic calibration and a spatially homogeneous aerosol field under high-fidelity stack conditions (50 °C, 90% RH). Validation was conducted via a field intercomparison campaign at a coal-fired power plant using a portable β-ray PM monitor calibrated on the IDFWT. Although the instrument exhibited robust linearity against the gravimetric reference method (R^2 = 0.9999 in the laboratory; R^2 = 0.9507 in the field), a statistically significant negative bias (≈ −24%) persisted. This discrepancy reveals a fundamental limitation: replicating physical parameters alone is insufficient to guarantee on-site accuracy. We attribute this deviation to un-simulated, site-specific physicochemical matrix effects — principally the differential retention of particle-bound water and semi-volatile species between the β -ray and gravimetric methods, with aerosol composition a secondary factor. Consequently, we propose a “lab-certified, field-corrected” methodology, utilizing the IDFWT to decouple intrinsic instrument errors from site-specific physicochemical interferences, thereby providing a scientifically defensible pathway to bridge the gap between laboratory traceability and in-situ data integrity.