Input-output analysis of reactive nitrogen flows in industry and industrial nitrogen footprint

Various nitrogen (N) compounds, collectively called reactive nitrogen (Nr) in industry, account for considerable proportions in the global N cycle. Complication of the interactions between the industrial sectors has hindered our understanding of their dynamics. We developed a new model based on input-output analysis to investigate the direct and indirect Nr flows in Japanese industry. The model revealed that the final chemical production sector received the biggest amount of Nr as feedstocks among sectors in 2011 (intermediate compounds: Urea, nitric acid, and others). Applying the model, the Japanese N footprint of industrial products was found to be 770 Gg-N.

Nr in industry accounts for considerable proportion in the global N cycle. Complicated interactions between the industrial sectors has hindered our understanding of their dynamics. In this study, we introduced a novel method based on input-output analysis, to reveal the direct and indirect Nr flows for industry.