Air pollution from cruise ships may be harming the health of people living in port cities by increasing inflammation and vulnerability to viruses such as the common cold and COVID-19, according to research released on July 11. The study, conducted by the University of Southampton and published in Environment International, analyzed air quality within Southampton's port.
Researchers examined ultrafine particulate matter—particles smaller than one thousandth the width of a human hair—found in the air around the port. These particles were enriched with trace elements produced by burning shipping fuel. Laboratory tests showed that exposure to these particles led to increased inflammatory signals and weakened cells' defenses against viral infections like COVID-19 or the common cold.
The investigation included five sampling sites across Southampton's port area, such as a dock gate used for heavy goods vehicles, a container ship terminal, and a busy cruise terminal. A comparison site located five kilometers away provided baseline readings. Samples were collected during late spring and early summer as well as during winter at the cruise terminal when fewer cruise ships visited.
At the cruise terminal, higher levels of vanadium, nickel, and cobalt were detected in fine and ultrafine particulate matter during peak summer months compared to winter. Concentrations of these elements were also generally higher throughout the port than at the comparison site. Dr. Nat Easton from the University of Southampton said, "We see increases in concentration when the wind was coming from the direction of the cruise ships, and when cruise ship presence was higher." Easton added, "The higher concentrations at the cruise terminal than the rest of the port is perhaps due to increased emissions from 'hoteling' cruise ships compared to cargo ships, but difference in fuel origins and berth occupancy times may also play a role."
Further laboratory tests revealed that vanadium might contribute significantly to these effects. Professor Loxham said, "To study this further, we infected bronchial epithelial cells from healthy donors with human rhinovirus (the virus which causes the common cold) and also used a model of COVID-19 coronavirus infection." Loxham continued, "When exposed to vanadium, the number of copies of both viruses increased, indicating vanadium's role in diminishing cells' ability to prevent viral replication. This has potential implications for severity and spread of infection."
The researchers suggest their findings support calls for reducing emissions from ships near populated areas through measures such as shoreside power using clean energy sources or improved emissions reduction technology. They also recommend enhanced monitoring of ultrafine particulate matter around ports worldwide.
