Accounting for the nitrogen footprint of food production in Chinese provinces during 1998–2018

Excessive emission of reactive nitrogen (Nr) in the environment has a negative impact on human health and biodiversity and aggravates the greenhouse effect. Food production and consumption is the primary source of anthropogenic Nr emissions. Currently, the research on China's nitrogen footprint lacks the exploration of regional differentiation, and the local virtual Nitrogen factor (VNF) is also insufficient. In this study, we developed localized VNF at the provincial level in China and then applied them to measure the per capita food production Nitrogen footprint of 31 provinces in mainland China from 1998 to 2018 by employing a modified N-Calculator model. We found that the national per capita food production N footprint varied from 15.30 to 21.09 kg/year over the past 20 years. Per capita food production N footprint of 29 provinces increased, ranging from 13% to 113%. The dominance of the food production N footprint of meat gradually increased, and the differences between regions showed a decreasing trend. Finally, we compared the results with different countries based on VNF and 2018 food consumption data. Although the limitations of the underlying data and parameters pose challenges to the accuracy of the estimation, our study provides an original data contribution to nitrogen footprint research to scientific communities and policymakers.