Air pollution from cruise ships may be harming the health of residents in port cities by increasing inflammation and vulnerability to viruses such as COVID-19 and the common cold, according to research published on July 10 by the University of Southampton.
The study, published in Environment International, analyzed air quality within Southampton's port. Researchers found that the air contained ultrafine particulate matter—particles smaller than one thousandth the width of a human hair—enriched with trace elements produced by burning shipping fuel. Laboratory tests showed these particles elevated inflammatory signals and weakened cells' defenses against viral infections like COVID-19 or the common cold.
Matthew Loxham, Professor of Respiratory Biology and Toxicology at the University of Southampton and senior author of the study, said, "In this research we've identified a clear air pollution 'signature' coming from cruise ships burning fuel in ports." The team conducted an in-depth investigation into both the composition and toxicology of particulate matter within a busy port for the first time.
Researchers selected five sampling sites around Southampton's port area—including a dock gate used for heavy goods vehicles, a container ship terminal, and a busy cruise terminal—as well as a comparison site located five kilometers away. Samples were collected during late spring and early summer as well as during winter at the cruise terminal when fewer ships visited. Higher levels of vanadium, nickel, and cobalt were detected in fine and ultrafine particulate matter at the cruise terminal during peak season compared to quieter months. Concentrations were also generally higher across all areas within the port than at the comparison site.
Dr. Nat Easton, lead author from the University of Southampton, said, "We see increases in concentration when wind was coming from direction of cruise ships, and when cruise ship presence was higher." Easton added that higher concentrations at terminals could be due to increased emissions from hoteling ships compared to cargo vessels or differences in fuel origins or berth occupancy times.
Laboratory tests using lung lining cells indicated increased expression of genes related to inflammation alongside decreased expression related to antiviral response after exposure to summer-season ultrafine particles from cruise terminals. Additional experiments suggested vanadium played a role; Loxham explained, "When exposed to vanadium, number of copies of both viruses increased indicating vanadium's role in diminishing ability of cells to prevent viral replication. This has potential implications for severity and spread of infection." The researchers recommend reducing emissions through shoreside power sourced from clean energy or alternative fuels along with enhanced monitoring for better regulation.
