Formulation-resolved VOC emission factors measured in a dynamic chamber and corresponding secondary formation...

Architectural paints represent an important source of volatile organic compounds (VOCs) in urban environments. The ongoing shift from solvent-based to water-based formulations can substantially alter VOC composition, emission factors, and associated secondary formation potentials; however, these effects remain poorly quantified and may introduce biases in current emission inventories. In this study, dynamic-chamber evaporation experiments were performed on selected architectural paint products spanning water-based and solvent-based formulations to obtain their VOC composition profiles and emission factors and to estimate their ozone formation potential (OFP) and secondary organic aerosol formation potential (SOAP). The selected water-based paints were dominated by oxygenated VOCs (OVOCs) and alkenes, with an average total emission factor of 56 g VOC kg^-1 paint. In contrast, the solvent-based products contained abundant alkanes, OVOCs, and aromatics, resulting in a higher total emission factor of 228 g VOC kg^-1 paint. For the water-based products, the emission-factor-derived OFP was 90 g O₃ kg^-1 paint, mainly contributed by acetaldehyde and limonene, while the SOAP was 0.8 g SOA kg^-1 paint and was also dominated by limonene. In solvent-based products, the emission-factor-derived OFP and SOAP were 482 g O₃ kg^-1 paint and 5.3 g SOA kg^-1 paint, respectively, with aromatics (e.g., toluene and ethylbenzene) and alkanes (e.g., n-octane) being the major contributors to both. Comparison between the mass-fraction- and emission-factor-based calculations showed distinct OFP and SOAP estimates, indicating that apportioning total emissions according to VOC composition may affect the accuracy of assessments of secondary pollution formation potentials. This study provides compound-specific and formulation-resolved emission factors for the selected architectural paint products and suggests that emission-factor-based characterization offers a more reliable assessment of their secondary formation potentials.