A MAP (Monitoring-Assessment-Priority) framework for amine degradation products in carbon capture

Amine-based chemical absorption is among the most mature technologies for point-source carbon capture. However, solvent emissions, including amine degradation products (ADPs), are considered emerging pollutants, raising environmental concerns. While amine emissions have been extensively studied, knowledge on ADPs remains limited. Herein, we propose a MAP (Monitoring-Assessment-Priority) framework, applied to three carbon capture plants. A total of 55 ADPs across eight categories were identified in flue gas, with concentrations ranging from 16.8 to 43.4 mg/Nm³ and emission factors averaging 243 ± 242 g/t CO₂. Under current emission scenarios and carbon capture targets, cumulative ADP emissions are projected to reach 354 Gg in China and 1218 Gg globally. Secondary aerosols formation potential of ADPs was estimated at 19.1 g/t CO₂, underscoring the need to consider secondary emissions alongside primary emissions. Over 50 % of ADPs exhibited higher ecotoxicity than parent amines, with ammonia dominating total ecotoxicity (69.1-83.9 %). Non-carcinogenic risks were mainly associated with alcohols, cyclic compounds, and nitrosamines, while carcinogenic risks were dominated by alcohols, nitrosamines, and aldehyde and ketone. Based on integrated rankings from above results, nine ADPs, such as ammonia, 3-aminopyrrolidine, and formaldehyde, were identified as priorities. The MAP framework provides a transferable approach to assess ADP emissions and prioritize compounds across solvent systems, offering actionable insights to help minimize environmental challenges associated with climate solutions.