Unexpected response of nitrogen deposition to nitrogen oxide controls and implications for land carbon sink.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 35668096.
- Also identified by DOI 10.1038/s41467-022-30854-y and PMC identifier 9170707.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
Terrestrial ecosystems in China receive the world's largest amount of reactive nitrogen (N) deposition. Recent controls on nitrogen oxides (NO<sub>x</sub> = NO + NO<sub>2</sub>) emissions in China to tackle air pollution are expected to decrease N deposition, yet the observed N deposition fluxes remain almost stagnant. Here we show that the effectiveness of NO<sub>x</sub> emission controls for reducing oxidized N (NO<sub>y</sub> = NO<sub>x</sub> + its oxidation products) deposition is unforeseen in Eastern China, with one-unit reduction in NO<sub>x</sub> emission leading to only 55‒76% reductions in NO<sub>y</sub>-N deposition, as opposed to the high effectiveness (around 100%) in both Southern China and the United States. Using an atmospheric chemical transport model, we demonstrate that this unexpected weakened response of N deposition is attributable to the enhanced atmospheric oxidizing capacity by NO<sub>x</sub> emissions reductions. The decline in N deposition could bear a penalty on terrestrial carbon sinks and should be taken into account when developing pathways for China's carbon neutrality.
Medical subject headings
- Air Pollutants
- Nitrogen