COMMUNICATIONS EARTH & ENVIRONMENT | _https://doi.org/10.1038/s43247-023-01050-7 
ARTICLE 
A 
JO 
mE Number of infringements 
EENumber of penalties 
— Mean number of penalties 
— Mean number of infringements 
- 35 
Port inspections on sulfur and NO, infringements 
Results within the Bonn Agreement. The results of the sulfur 
infringements from most BA CPs follow an increasing trend 
between 2015 and 2020 (Supplementary Fig. 6A). The primary 
reason for this is that not all CPs immediately implemented 
inspection protocols; needed to gain experience; and had initially 
only limited information available to single out suspicious OGVs 
for inspection. As a result, not all CPs have inspection results for 
2015. From 2016, all BA CPs were actively conducting inspections 
within their ports. During this time, remote monitoring opera- 
tions and the exchange of alerts via Thetis-EU began to gain 
momentum, leading to the discovery of a higher number of 
infringements and deficiencies. 
Due to a high number of observed sulfur infringements by one 
BA CP, the total observed number of infringements in the years 
2015 and 2016 still provided the highest number of observed 
infringements (243 and 223) (Fig. 4A). The year 2018 provided 
the third highest number of recorded infringements (178). 
However, following that year, the number of identified infringe- 
ments began to decline. It is important to note that the EU 
Sulphur Directive mandates Member States (MS) to provide port 
inspection data by June, as a result, at the time of publication, not 
all CPs were able to submit data for the year 2022. 
The EU-Commission Implementing Decision played an 
important role in maintaining a consistent number of inspections 
conducted on OGVs throughout the entire time period. Although 
there was a decrease in inspections in 2020 due to the global 
pandemic, the majority of CPs were still able to fulfill the 
mandatory inspection requirements. It is worth noting that in this 
context, numerous CPs utilized the exemption outlined in the 
implementing Decision to reduce the number of inspections by 
mplementing remote monitoring (Art 3.3(a))°. 
Regarding the reported penalties on sulfur, an upward trend 
was observed between the years 2015 and 2017, reaching a peak of 
126 cases in 2017 (Supplementary Fig. 6B). Subsequently, the 
aumber of penalties declined. It should be noted that there is a 
time lag in the reporting of penalties, as often the reported 
penalties correspond to infringements observed in the previous 
year. Therefore, the peak in penalties in 2019 aligns with the peak 
of infringements in 2018. To address this time lag, it is necessary 
to analyze the data from the original cases and assign them to the 
year of observation. However, this analysis was not feasible due to 
the sensitive nature of the legal cases involved. 
When looking at the mean number of sulfur deficiencies and 
:nfringements observed by the BA CPs’ port inspection 
authorities, a substantial decrease was observed after the global 
sulfur cap came into effect (Fig. 4A). Over the total period 
2015-2022, 996 infringements were observed of which 544 were 
venalized. In the period 2015-2020, before the global sulfur cap 
came into effect, 885 infringements were observed by the port 
‘nspection authorities with a mean of 21.6 cases per year, 442 
penalties were executed in the same period or on average 10.8 
penalties per year, corresponding to 56% of the infringements. In 
the period 2020-2022, after the global sulfur cap came into force, 
a total of 111 infringements were observed. The mean annual 
aumber of observed deficiencies per BA CP decreased therefore 
significantly to 4.8 cases per year (P<0.001). In total, 102 
penalties were handed out after the global sulfur cap came into 
affect (91%). The mean number of penalties per BA CP per year 
therefore decreased significantly to 4.3 penalties (P < 0.05), which 
‚Ss just below the mean number of observed infringements, 
ındicating that as of today there is a good legal follow-up of 
possible infringements within the BA. 
There is a notable disparity between sulfur and NO. The result 
of the inquiry with the BA CPs provided proof of the successful 
enforcement and legal follow-up for sulfur infringements. In 
250 
- 30 
2 200 
25 
2 450 . 
5 150 
20 * 
2 400 4 
50 
5 
10% 
Q 
(3) 
| 
0 
4 nn A, an ad 
2015 2016 2017 2018 2019 2020 2021 2022 
Year 
m Number of infringements 
mıNumber of penalties 
— Mean number of infringements 
J 
5 
5 
5 
5 | 
= 
2 
41 
9 
= 
3 > 
3 
rm 
‘4 
bu ———— ii —— — 
2015 2016 2017 2018 2019 2020 2021 2022 
Year 
” 
© 
J 
Fig. 4 Number of observed infringements and penalties in the Bonn 
Agreement. Infringements observed by port inspection authorities for SO- 
(A) and NO, (B). Note that for 2022 not all BA CPs were yet able to 
provide data. 
higher emission factors and a greater non-compliance rate 
for Tier II OGVs compared to Tier I OGVs. The Danish study 
also confirmed that OGVs emit more NO, when operating at 
lower engine loads. Additionally, the results demonstrated that 
larger engines generate higher emission factors, which is in 
line with the Belgian measurements, albeit with a weak 
correlation. An increasing trend was observed across all Tier 
levels, excluding Tier III due to limited measurements (Supple- 
mentary Fig. 5). 
Non-compliance with NO, standards has also recently been 
investigated within the SCIPPER project. A particular emphasis 
was placed on Tier II OGVs. The advantage of the enforcement 
of Tier III OGVs is that a not-to-exceed limit is defined for all 
four engine load points, set at 50% of the applicable emission 
limit (Appendix II, MARPOL Annex VI)! However, because the 
keel laying date (KLD) is defined in the MARPOL Annex VI 
regulations to determine Tier II classification, the large majority 
(73%) of the recently constructed OGVs are registered with a 
KLD prior to 2021. Consequently, they are subjected to the Tier IT 
emission limits instead of the stricter Tier III emission limits?*. 
In total 65 Tier III OGVs were monitored by the SCIPPER 
partners. The findings indicated that approximately half of the 
observed Tier III OGVs did not comply with the maximum NO, 
emission limits for Tier III; ca 20% of the observed Tier II OGVs 
did not even meet Tier II emission limits®. This observation 
aligns with the limited Tier III non-compliance results reported 
by Belgium, where a non-compliance rate of 43% was observed. 
Various other studies have also highlighted concerns regarding 
elevated levels of NO, emissions from Tier II OGVs?34, 
COMMUNICATIONS EARTH & ENVIRONMENT | (2023)4:391 | https: //dol.0rg /1C.1038/s43247-023-01050-7 | www.nature.com/commsenv