Unlocking nitrogen management potential via large-scale farming for air quality and substantial co-benefits

Baojie Li; Hong Liao; Ke Li; Ye Wang; Lin Zhang; Yixin Guo; Lei Liu; Jingyi Li; Jianbing Jin; Yang Yang; Cheng Gong; Teng Wang; Weishou Shen; Pinya Wang; Ruijun Dang; Kaihua Liao; Qing Zhu; Daniel J Jacob

doi:10.1093/nsr/nwae324

Unlocking nitrogen management potential via large-scale farming for air quality and substantial co-benefits

Natl Sci Rev. 2024 Sep 13;11(10):nwae324. doi: 10.1093/nsr/nwae324. eCollection 2024 Oct.

Authors

Baojie Li¹, Hong Liao¹, Ke Li¹, Ye Wang¹, Lin Zhang², Yixin Guo³, Lei Liu⁴, Jingyi Li¹, Jianbing Jin¹, Yang Yang¹, Cheng Gong⁵, Teng Wang⁶, Weishou Shen¹, Pinya Wang¹, Ruijun Dang⁷, Kaihua Liao⁸, Qing Zhu⁸, Daniel J Jacob⁷

Affiliations

¹ Collaborative Innovation Center of Atmospheric Environment and Equipment Technology, Jiangsu Key Laboratory of Atmospheric Environment Monitoring and Pollution Control, School of Environmental Science and Engineering, Nanjing University of Information Science and Technology, Nanjing 210044, China.
² Laboratory for Climate and Ocean-Atmosphere Studies, Department of Atmospheric and Oceanic Sciences, School of Physics, Peking University, Beijing 100871, China.
³ Earth, Ocean and Atmospheric Sciences Thrust, Function Hub, Hong Kong University of Science and Technology (Guangzhou), Guangzhou 511442, China.
⁴ College of Earth and Environmental Sciences, Lanzhou University, Lanzhou 730000, China.
⁵ Department of Biogeochemical Signals, Max Planck Institute for Biogeochemistry, Jena 07745, Germany.
⁶ College of Oceanography, Hohai University, Nanjing 210024, China.
⁷ John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA 02138, USA.
⁸ Key Laboratory of Watershed Geographic Sciences, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, China.

Abstract

China's sustained air quality improvement is hindered by unregulated ammonia (NH₃) emissions from inefficient nitrogen management in smallholder farming. Although the Chinese government is promoting a policy shift to large-scale farming, the benefits of this, when integrated with nitrogen management, remain unclear. Here we fill this gap using an integrated assessment, by combining geostatistical analysis, high-resolution emission inventories, farm surveys and air quality modeling. Smallholder-dominated farming allows only 13%-31% NH₃ reduction, leading to limited PM_2.5 decreases nationally due to non-linear PM_2.5 chemistry. Conversely, large-scale farming would double nitrogen management adoption rates, increasing NH₃ reduction potential to 48%-58% and decreasing PM_2.5 by 9.4-14.0 μg·m^-3 in polluted regions. The estimated PM_2.5 reduction is conservative due to localized NH₃-rich conditions under large-scale livestock farming. This strategy could prevent over 300 000 premature deaths and achieve a net benefit of US $68.4-86.8 billion annually, unlocking immense benefits for air quality and agricultural sustainability.

Keywords: air quality; ammonia emission; large-scale farming; nitrogen management.