Urban nitrogen budgets: evaluating and comparing the path of nitrogen through cities for improved management

Kaltenegger, Katrin; Bai, Zhaohai; Dragosits, Ulrike ORCID: https://orcid.org/0000-0002-9283-6467; Fan, Xiangwen; Greinert, Andrzej; Guéret, Samuel; Suchowska-Kisielewicz, Monika; Winiwarter, Wilfried; Zhang, Lin; Zhou, Feng. 2023 Urban nitrogen budgets: evaluating and comparing the path of nitrogen through cities for improved management [in special issue: Nitrogen in agro-food systems and the environment] Science of The Total Environment, 904, 166827. 13, pp. https://doi.org/10.1016/j.scitotenv.2023.166827

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Official URL: http://dx.doi.org/10.1016/j.scitotenv.2023.166827

Abstract/Summary

Reactive nitrogen (Nr) released to the environment is a cause of multiple environmental threats. While Nr flows are often only analyzed in an agricultural context, consumption and emission takes place in the urban environment, and opportunities for Nr recycling and effective policy implementation for mitigation often appear in cities. Since little information is available on the bigger picture of Nr flows through the urban environment, these opportunities often remain unexploited. Here we developed a framework to model Nr pathways through urban and surrounding areas, which we applied to four test areas (Beijing and Shijiazhuang (China), Vienna (Austria), and Zielona Góra (Poland)). Using indicators such as recycling rates and Nr surplus, we estimated environmental risks and recycling potentials based on Nr flows and their entry and exit points. Our findings show marked differences between the core and surrounding areas of each city, with the former being a site of Nr consumption with largest flows associated with households, and the latter a site of (agricultural) production with largest flows associated with industry (fertilizers) and urban plants. As a result, Nr transgresses the core areas in a rather linear manner with only 0–5 % being re-used, with inputs from Nr contained in food and fuels and outputs most commonly as non-reactive N2 emissions to the atmosphere from wastewater treatment and combustion processes. While the peri-urban areas show a higher Nr recycling rate (6–14 %), Nr accumulation and emissions from cultivated land pose significant environmental challenges, indicating the need for mitigation measures. We found potential to increase nitrogen use efficiency through improved Nr management on cultivated areas and to increase Nr recycling using urine and sewage sludge as synthetic fertilizer substitutes. Hence our framework for urban nitrogen budgets not only allows for consistent budgeting but helps identify common patterns, potentially harmful flows and Nr recycling potential.

Item Type:	Publication - Article
Digital Object Identifier (DOI):	https://doi.org/10.1016/j.scitotenv.2023.166827
UKCEH and CEH Sections/Science Areas:	Atmospheric Chemistry and Effects (Science Area 2017-)
ISSN:	0048-9697
Additional Information. Not used in RCUK Gateway to Research.:	Open Access paper - full text available via Official URL link.
Additional Keywords:	nitrogen, urban, environment, circularity, air pollution, water pollution
NORA Subject Terms:	Ecology and Environment Atmospheric Sciences
Date made live:	09 Nov 2023 14:23 +0 (UTC)
URI:	https://nora.nerc.ac.uk/id/eprint/536063

Item Type:

Publication - Article

Digital Object Identifier (DOI):

https://doi.org/10.1016/j.scitotenv.2023.166827

UKCEH and CEH Sections/Science Areas:

Atmospheric Chemistry and Effects (Science Area 2017-)

ISSN:

0048-9697

Additional Information. Not used in RCUK Gateway to Research.:

Open Access paper - full text available via Official URL link.

Additional Keywords:

nitrogen, urban, environment, circularity, air pollution, water pollution