Contribution of concrete nitrogenation to global NOx uptake

Abstract

The renewal and expansion of the built environment within the context of rapid urbanization are imposing new benchmarks for resource management, particularly concerning the billions of tons of consumption and waste generation of concrete materials. The commercialization of carbonation in cementitious materials is underway, opening up possibilities for nitrogenation that has been well documented in recent experimental studies. Here we further utilize a dynamic model to estimate the mitigation potentials of NOx by the promotion of concrete nitrogenation in a global urbanization scenario, projecting its global health and economic benefits toward 2050. Our analysis reveals that concrete nitrogenation can theoretically contribute to a reduction in NOx emissions by approximately 3.4–6.9 Mt—or 6–13% of global industry-related emissions—in 2021. The cumulative economic potential is projected to exceed 150–160 trillion USD, accompanied by a NOx mitigation of 131–384 Mt between 2021 and 2050, equivalent to 75–260 years potentially lost to premature death and reduced quality of life (estimated in terms of disability-adjusted life years). However, both carbonation and nitrogenation techniques rely on the availability of alkaline reactive components within the material, leading to competition. Although significant uncertainty remains, our comparison reveals that, in most regions, promoting the commercialization of nitrogenation exhibits higher feasibility and prioritization over carbonation in relation to both economic and environmental benefits. Globally, concrete materials are widely used to build urban settings, resulting in massive waste. The authors propose scenarios of industrial-scale application of concrete nitrogenation, to use concrete debris in cities to mitigate NOx emissions.