Odor emissions in organic waste composting: Molecular mechanisms, control technologies, and future perspectives

• Multiscale framework integrates bibliometrics, molecular mechanisms, and engineering. • Feedstock C/N ratio and microbial consortia govern NH 3 /H 2 S emission dynamics. • Self-reinforcing microenvironments drive odorant formation. • Biochar-mineral composites can efficiently reduce NH 3 and H 2 S via cascading effects. • AI-driven flux prediction bridges molecular-to-system disconnects. Organic waste composting, a cornerstone of circular bioeconomy strategies, faces critical challenges in malodorous emissions that impede social acceptance and environmental sustainability. Moving beyond isolated perspectives, this review establishes a novel integrative multiscale framework that uniquely bridges macro-scale research trend analysis with micro-scale molecular pathway deciphering, and critically evaluates future-facing technologies. Unlike preceding reviews, this work synthesizes a translational perspective that explicitly links macroscale research trends with microscale molecular mechanisms, and critically evaluates technologies through a sustainability lens. Through systematic analysis of 1,268 global studies (2010-2024), nitrogenous (NH 3 /amines) and sulfurous (H 2 S/methanethiol) compounds are identified as dominant odorants, governed by feedstock C/N ratios, microbial consortia dynamics, and self-reinforcing microenvironmental gradients. Though the application of in-situ approaches showed promise in improving thermophilic phases, integration with ex-situ strategies can potentially yield significant reduction in NH 3 and H 2 S release through a systematic adsorption-precipitation process. Recent research results show that non-thermal plasma (NTP) processes possess high odor removal efficiency, though largely constrained by energy intensity at scale. Other critical barriers yet to be addressed include the translation from molecular-to-engineering disconnects, pronounced geographical data bias and environment-energy tradeoffs. In this review, three disruptive frontiers are proposed: 1) Sub-nanometer investigation of enzymatic interfaces, 2) AI-driven dynamic odor flux prediction systems, and 3) Intelligent modular units coupling bioinspired catalysis with synthetic biology for odor elimination. Aligned with cumulative emission standards and tropical infrastructure incentives, this roadmap positions odor-regulated composting as a sustainable bioconversion platform that bridges fundamental research and community-engaged governance, offering actionable pathways for global decarbonization efforts.