University Finds Cruise Ship Ventilation Strategies May Help Prevent Super-Spreader Events

Published on: 19 Jan, 2025
Updated on: 19 Jan, 2025

University of Surrey staying ahead of the next pandemic

Cruise ships, often labelled as coronavirus hotspots during the pandemic, have been the focus of new research from the University of Surrey aimed at reducing onboard disease transmission risks. The study emphasizes the need for targeted ventilation strategies, particularly in crowded dining spaces, to help the cruise industry build resilience against future health crises.

The research, conducted 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 team assessed indoor air quality (IAQ), ventilation, thermal conditions, and airborne infection risk aboard a ship carrying more than 5,000 passengers between UK and EU ports.

Researchers monitored CO2 levels, temperature, and humidity across nine onboard environments and identified gaps in current ventilation practices. While most areas were sufficiently ventilated, over-ventilation in spaces like theatres and cabins and under-ventilation in crowded dining areas highlighted the need for targeted improvements.

Professor Prashant Kumar, founding director of GCARE, commented on the findings: “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.”

Key Findings

Using CO2 levels as a proxy for exhaled breath, the study found a very low probability of airborne infection transmission during normal speaking conditions, at less than three per cent. This was attributed to sufficient ventilation relative to occupancy in most areas.

However, high-occupancy spaces where voices are raised, such as dining areas and social settings during peak times, saw increased CO2 levels, indicating a need for additional mitigatory measures.

The research also highlighted challenges posed by port emissions. Elevated ambient CO2 levels linked to marine traffic and port operations were observed in berths, particularly in dining areas near open spaces. While air conditioning systems worked consistently during docking, ventilation struggled to fully mitigate pollution, underscoring the need for improved filtration systems and adaptive ventilation both at sea and in port.

Practical Solutions for a Safer Future

Ho Yin Wickson Cheung, a PhD student at GCare, who worked on the project, stressed the importance of the study’s insights: “The insights from this study will serve as a valuable guide for cruise operators, many of whom have first hand experience with the challenges of viral transmission. These simple measures, backed by science, provide practical solutions to help ensure the wellbeing of everyone onboard.”

The study provides actionable recommendations, including:

• Implementing adaptive ventilation strategies for high-occupancy areas.
• Improving filtration systems to mitigate outdoor pollutants.
• Optimizing energy use in over-ventilated spaces without compromising air quality.

These measures can help cruise operators maintain passenger safety while improving energy efficiency and building resilience against future pandemics.

By addressing the critical issue of onboard ventilation, this research sets the stage for further exploration and provides cruise operators with the tools needed to safeguard passengers in the event of another health crisis.

Funding

The Healthy Sailing project is funded by the European Union’s Horizon programme and coordinated by the University of Thessaly’s Laboratory of Hygiene and Epidemiology.

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