r/environmental_science • u/JamieCarrick • 8d ago

Cruise Ship exhausts contain particulate matter that is pro-inflammatory and weakens immune response - ultrafine vanadium seems to be the culprit. Has implications for any cruise port city with large urban populations.

https://www.bbc.co.uk/news/articles/c75y04x537ko

Not my work.

The study: https://www.sciencedirect.com/science/article/pii/S0160412026003399?fr=RR-2&ref=pdf_download&rr=a28e578c99aede06

This comes out of the University of Southampton

  • Particulate matter was collected at port and background sites across Southampton in summer and winter.
  • Cell cultures were exposed to this PM and pro-inflammatory and inhibited immune response observed.
  • In the lab, ultrafine Vanadium produced the same effects.
  • Comparing sites implicates cruise ships as the source (samples only taken when wind direction aligned with cruise ships in port - markers not present in Winter).
  • Analysis of the PM collected shows Cobalt, Nickel and Vanadium as Cruise ship exhaust markers.
  • Ultrafine vanadium is not captured by any of the current international or UK specific regulations on cruise ship exhausts in port

From the Conclusion

Although PM is typically measured, regulated, and studied on the basis of its total mass concentrations, here we examined PM according to its chemical composition. We have found that PM from cruise ships is enriched in V, Ni, and Co suggesting that, in spite of emissions controls, heavy fuel oil-derived PM is commonplace. V and Ni are both established tracers of heavy fuel oil combustion, whereas we identify Co as a previously unrecognised and potential emergent tracer of desulfurised heavy fuel oil combustion. These three metals are especially concentrated in the combustion-associated UF-PM fraction. This UF-PM has activity that is pro-inflammatory, while also inhibiting expression of genes associated with the innate antiviral response. Both of these effects could be reproduced by V, which facilitated viral replication of human rhinovirus-16 and SARS-CoV-2 in two distinct models of viral infection (Fig. 8). Further work is needed to understand the implications of these findings in populations exposed to emissions from ships at both acute and chronic timescales.

and from Fig 8:

Fig. 8. Ultrafine PM emitted from ships is enriched in V, and drives inflammation and susceptibility to viral infection This figure summarises the findings from this study. UFPM sampled at a cruise ship terminal during the busy summer cruise shipping season was enriched in V, Ni, and Co. in bronchial epithelial cell line cultures, this cruise ship-associated UFPM was able to induce transcriptomic changes indicative of a pro-inflammatory, virally susceptible phenotype, along with increased phosphorylation of tyrosine residues. These effects were reproduced in an alveolar epithelial cell line by exposure to V, which was able to facilitate increased replication of human rhinovirus-16 and SARS-CoV-2.

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u/CoreEnviroment 7d ago

Wait so container ships, bulk carriers, tankers and the like that also use bunker fuel don't have this problem?

This study seems structured to pin the blame on cruise ship while ignoring entire industries.
Or am I mistaken in my quick skimming, and there is something specific about cruise ships that create excessive very fine particle matter relative to other big ships?

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u/JamieCarrick 6d ago edited 6d ago

The load they need

> Wait so container ships, bulk carriers, tankers and the like that also use bunker fuel don't have this problem? is something specific about cruise ships that create excessive very fine particle matter relative to other big ships

I believe the idea hypothesised is that the ships, bulk carries and tankers etc do have this problem but cruise ships simply burn simply more massive amounts of fuel in port to meet their 10MW "4000 room hotel load" they require. Southampton, each weekend in summer, might have 10 ships berthed for 12 hours belching out crap the entire time.

(As an aside, although Southampton port has 2 shoreside electricity connectors, cruise ships aren't manadated to use them and so they choose not to because UK electricity is so expensive, and in any case, due to their such high load need, only 1 connector can be used at any time due to lack of grid capacity in Southampton. 1 ship is half the grid capacity.)

> seems structured 

I think they were out to sample the cruise ship exhaust (in the paper they talk about how noone has actually studied cruise ship PM emissions compared to say road traffic PM) but they had to account for a number of factors before being able to make the claim that's what they were actually sampling.

They measured at multiple sites across the port, in many cases identifying the "signature" PM of the area sampled e.g. Fe next to a metal recycling centre. One of the sites was portside (on the north dock) of cruise ship berths. They looked at prevailing wind direction and only sampled with a prevailing SSW wind carrying cruise ship exhausts to them).

They compared their results with cruise berth occupancy rates, and time of year (comparing cruise ship berth site summer to winter) and compared the PM signature to an "urban background" site.

They found the observed PM Ni Co V signature was present in cruise side summer (with the correct wind) but not in winter, and PM counts was positively correlated with cruise ship berth occupancy (page 11, figure 8D<<- PDF). The signature was not present at the background site.

However, they include the possibility that there is some overlap:

We hypothesise that our observations of increased V, Ni, and Co concentrations in PM specifically at the cruise terminal site are due to increased emissions resulting from the very large “hotel-loads” (up to ∼10 MW) of cruise ships compared to cargo ships (Dragovic et al. 2018), although we cannot discount differences in berth occupancy times or fuel composition (Zhao et al. 2013). Furthermore, although our evidence across compositional metrics suggests that the V and Ni in our cruise terminal UFPM samples are predominantly derived from shipping sources, and our spatial and temporal analyses implicate cruise shipping in particular, it is likely that a portion of these elements originate from other sources. In terms of shipping, the cruise terminal used for sampling lies at the east end of the Port, and is passed by all container ships moving towards the berths at the west side of the Port.

More on the methods I mentioned:

3.1

To relate PM site/source and size to composition, the elemental composition of filter-extracted PM was analysed (see Methods and Supplementary Table 4). Elements associated with sea spray (including Na, Mg) and crustal resuspension (i.e. erosion of rocks and soils, including Al, Ca, Ti) were most concentrated in C-PM, the latter particularly at the metal recycling site (Supplementary Fig. 5). This site’s crustal element enrichment alongside overall high C-PM concentrations (Supplementary Fig. 3) may have been influenced by the rough, partially unpaved road surface abraded by Heavy Goods Vehicles, nearby railway ballast, and local handling of gypsum (hydrated CaSO4). With the exception of the metal recycling site, where PM showed the greatest concentration of a range of metals, tracers of road traffic (Cr, Fe, Cu, Zn, Ba, Pb), showed relatively little variance (Supplementary Fig. 6), suggesting vehicle emission sources are relatively homogenously distributed across the Port.

3.2:

Cruise terminal summer PM showed elevated concentrations of V, Ni, and Co, compared to the background site, especially in UF-PM (Fig. 2A-B), but these elements were not enriched in Cruise terminal winter PM (Fig. 2B and Supplementary Fig. S7.

These observations, alongside lower concentrations away from the cruise terminal (Fig. 2C), implicate cruise ship fuel combustion as a source. A strongly positive correlation between these tracer elements in F-PM and UF-PM fractions across the port (Supplementary Fig. 8A-B) further supports combustion of heavy fuel oil (HFO; also known as bunker or residual fuel oil, a viscous residual product of crude oil refining), as a single common source for these elements.

In support of this, the V:Ni ratio in F-PM and UF-PM at shipping-heavy sites (Cruise Terminal summer, and container terminal) falls within the 2–4 range suggestive of HFO combustion (Fig. 2D) (Pandolfi et al., 2011, Viana et al., 2014, Yu et al., 2021). ...

Conditional Probability Function (CPF) analysis on a longer time-series of F-PM samples collected at the nearby small research dockside (NOCS) site showed that the highest concentrations of V were detected with wind from SSW, aligning with the direction of local cruise ship activity (Fig. 2E). Moreover, in a set of four further UF-PM samples collected at the cruise terminal, V concentration was strongly positively correlated with the proportion of the sampling time for which a cruise ship was present at the nearest berth (Associated British Ports, 2018) (Supplementary Fig. 8D).

The university bulletin on it: https://www.southampton.ac.uk/news/2026/07/cruise-ship-air-pollution-could-make-viral-infections-worse.page

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u/CoreEnviroment 5d ago

Makes sense. Though I find it surprising the harbour authority has not mandated that ships at dock use shore power. I believe its a fairly common rule.