Distributed carbon capture in urban environments: Emerging architectures for building-integrated CO₂ Removal

Urban environments, responsible for ~40% of global CO₂ emissions, demand innovative carbon capture, utilization, and storage (CCUS) solutions to achieve net-zero targets. Distributed carbon capture, integrating CO₂ removal into urban infrastructure, offers a scalable alternative to centralized systems, leveraging buildings as capture hubs. This review explores emerging architectures for building-integrated CO₂ removal in urban settings, focusing on modular direct air capture (DAC) units, CO₂-absorbing materials, HVAC-integrated systems, and hybrid urban-green infrastructures. Modular DAC units enable retrofitting, capturing CO₂ via sorbents like metal-organic frameworks, while carbon-absorbing concrete and algae-based facades provide passive sequestration. HVAC systems utilize existing airflow for efficient capture, and hybrid systems combine with urban forests for synergistic benefits. The paper synthesizes recent advancements, evaluating technical feasibility, energy demands, and economic viability. Case studies, including Climeworks’ Zurich DAC (900 tons CO₂/year) and Hamburg’s BIQ House algae facades, illustrate practical applications but highlight scalability limits. Environmental co-benefits, such as improved air quality, and social impacts, including public perception, are assessed. Challenges, ranging from high energy costs, urban policy gaps, to CO2 storage constraints persist, necessitating material innovations and regulatory incentives. This review underscores distributed CCUS’s potential to decarbonize cities, proposing a roadmap for scaling through interdisciplinary collaboration. By addressing technical and societal barriers, building-integrated CO₂ removal can redefine urban climate strategies, aligning with global sustainability goals.