Southampton cruise ship emissions more harmful than road traffic, study finds

More than 2.5 million cruise passengers travelled through Southampton in 2025. It is also the UK’s leading vehicle and deep-sea trading port. You can see the ships and port machinery from miles around. All of this is downwind of a city of 260,000 people.

A team of 32 researchers began investigating air pollution from the docks in 2018. Their research has revealed that the types of air pollution that come from ships may be more harmful than those from road traffic.

With help from the port staff, the team spent more than two years sampling air pollution in the port. Each source had different characteristics. Downwind of the cruise terminal, the air pollution had a clear signature with tiny ultrafine particles, smaller than the wavelength of light, containing metals including vanadium, nickel, cobalt and molybdenum.

The researchers also looked at how the ultrafine particles collected near the cruise terminal affected lung cells, including tests on cells donated by people in Southampton.

Prof Matthew Loxham, the project leader from the University of Southampton, said: “The ultrafine particles in these ships’ emissions were more able to drive cells to release a range of chemical communication signals associated with inflammation and reduce their ability to prevent the replication of viruses.”

Further tests suggested that this cell inflammation and reduced ability to resist common viruses was due to vanadium particles. There was a clear relationship between ultrafine vanadium downwind of the cruise terminal and the number of cruise ships in port.

Loxham said: “When crude oil is refined, naturally occurring vanadium tends to be concentrated into the heavy fuel as petrol and kerosene are removed. When heavy fuel oil, which is used by many ships, is combusted, a portion of the metal vaporises and ends up in the exhaust.”

Dr Nat Easton, one of the researchers, said: “I was surprised how much more vanadium and nickel was in the cruise ship-associated particles than the container ship-associated particles. At times, all five cruise terminals have a ship in port, and a cruise ship can house over 5,000 passengers. Each of these can have their engines running for heating, hot water, lighting and cooking in a way that cargo ships do not need to.”

A spokesperson for Associated British Ports (APB) said: “The port of Southampton is a leader in introducing measures to improve air quality, being the first port in the UK to introduce large-scale shore power connections so vessels can shut off their engines at berth.” About 15% of cruise ships now use shore power.

APB voiced concerns about aspects of the methodologies in the study and the strength of inference in some of the findings that have been presented to the media.

There are no measurements to assess the spread of ultrafine particles or vanadium from the port. Easton said: “These harmful effects were linked to both chemical composition and ultrafine particles. Neither [are] routinely monitored.”