Crowded dining spaces were identified as priority areas for improved air circulation in new research undertaken to mitigate future health threats on board cruise ships.
To help the industry build resilience against health threats, the UK University of Surrey’s research team, who undertook the research, emphasised the importance of targeted ventilation strategies to reduce on board disease transmission risk.
During the pandemic, cruise ships became known as coronavirus hotspots, causing most of them to suspend operations for months.
This study, led by Surrey’s Global Centre for Clean Air Research (GCARE) as part of Horizon Europe’s HEALTHY SAILING project, involved collaboration between international experts from the UK, Europe, and the cruise industry.
The researchers assessed indoor air quality (IAQ), ventilation, thermal conditions and airborne infection risk on board a ship carrying more than 5,000 pax between UK and EU ports.
By monitoring CO2 levels, temperature and humidity in nine different on board environments, they revealed gaps in current ventilation practices, including over-ventilation in theatres and cabins, offering actionable recommendations to enhance safety and energy efficiency.
“The COVID-19 pandemic brought unprecedented challenges to the cruise industry, with passenger ships often labelled ‘hotspots’ for super-spreading events. While significant progress has been made with indoor air quality management across the sector, there remains a clear need for targeted ventilation strategies in high-occupancy areas and energy optimisation in over-ventilated spaces.
“These findings provide a comprehensive roadmap for a healthier and more resilient cruise industry,” claimed Prof Prashant Kumar, Co-Director, Institute for Sustainability, Professor and Chair in Air Quality and Health; Founding Director, Global Centre for Clean Air Research (GCARE) (pictured).
Using CO2 concentrations as a proxy for exhaled breath, the study found the probability of airborne infection transmission during normal speaking conditions to be very low, at less than 3%. This was primarily due to sufficient ventilation in most areas relative to occupancy levels.
However, in higher occupancy areas where voices are raised to be heard – for example, dining areas and other social settings at peak times – CO2 levels increased, suggesting additional mitigatory measures were required.
Researchers also identified challenges from port emissions impacting IAQ on board the cruise ship, with elevated ambient CO2 levels in berths linked to marine traffic and port operations.
Dining areas (buffet, pubs and restaurants) were particularly susceptible to outdoor pollutants, due to their proximity to open spaces and high occupancy. Despite stable air conditioning during docking, ventilation systems struggled to fully mitigate pollution, highlighting the need for better filtration and adaptive ventilation both at sea and in port.
By implementing adaptive ventilation strategies on board, including targeted filtration systems where necessary, cruise operators can ensure passenger wellbeing and safety, while improving energy efficiency in over ventilated spaces without compromising air quality.
This research sets the stage for further exploration and provides a basis for building resilience in the event of another health crisis.
The HEALTHY SAILING project is funded by the EU’s HORIZON programme. It is co-ordinated by the University of Thessaly’s Laboratory of Hygiene and Epidemiology and supported by UKRI under the UK government’s Horizon Europe funding guarantee. Additional funding was provided by the Swiss State Secretariat for Education, Research and Innovation (SERI).
Reference:
Cheung, W., Kumar, P., Sarkawt, H., Emygdio, A., Wei, Y., Anagnostopoulos, L., Ewe, J., Ferracci, V., Galea, E., Grandison, A., Hadjichristodoulou, C., Jia, F., Lepore, P., Morawska, L., Mouchtouri, V., Siilin, N., Wang, Z., 2025. ’Monitoring of indoor air quality at a large sailing cruise ship to assess ventilation performance and disease transmission risk’. Science of the Total Environment, 178286.
