Year: 2023
Type: article
Abstract: . The nitrogen stable isotope composition (δ15N) of nitrogen oxides (NOx) is a powerful indicator for source apportionment of atmospheric NOx; however, δ15N–NOx values emitted from ships have not been reported, affecting the accuracy of source partitioning of atmospheric NOx in coastal zones with a lot of ocean vessel activity. This study systemically analyzed the δ15N–NOx variability and main influencing factors of ship emissions. Results showed that δ15N–NOx values from ships ranged from −35.8 ‰ to 2.04 ‰ with a mean ± standard deviation of −18.5 ± 10.9 ‰. The δ15N–NOx values increased monotonically with the ongoing tightening of emission regulations, presenting a significantly negative logarithmic relationship with NOx concentrations (p < 0.01). The selective catalytic reduction (SCR) system was the most important factor affecting changes in δ15N–NOx values, compared with fuel types and operation states of ships. Based on the relationship between δ15N–NOx values and emission regulations observed in this investigation, the temporal variation in δ15N–NOx values from ship emissions in the international merchant fleet was evaluated by developing a mass-weighted model. These simulated δ15N–NOx values can be used to select suitable δ15N–NOx values for a more accurate assessment of the contribution of ship-emitted exhaust to atmospheric NOx.
Language: English
Subfield: Environmental Engineering
Field: Environmental Science
Domain: Physical Sciences
SDG: Climate action
Open Access status: gold
Estimated APC paid: $1,725
Awards: G3685878488, G6054850460, G6160011579
OpenAlex ID: W4387634021