How to manage indoor air quality challenges on board ships

While comfort and ventilation may seem secondary compared to other operational priorities, the reality on board ships is that poor indoor air quality can quietly erode crew health and operational effectiveness. As ship crew typically spend months on board, a significant portion of their lives is spent in these enclosed environments. Marine heating, ventilation, and air conditioning (HVAC) systems which is vital for maintaining onboard comfort can inadvertently become breeding grounds for bacterial, viral, and mould contaminants. This makes indoor air quality (IAQ) a critical factor for their health, comfort, and operational performance. 

Evidence from occupational and health organizations confirms that exposure to elevated particulate matter and volatile organic compounds (VOCs) can impair respiratory function, trigger fatigue, reduce alertness, and impact cognitive performance. These factors increase risks of accidents and reduce overall operational efficiency. 

Understanding the root of the problem

Ships differ from land-based environments in several critical ways that increase microbial risk in HVAC systems. Poor ventilation, temperature fluctuations, and limited access for cleaning can result in moisture accumulation and organic deposit buildup inside ducts, creating ideal niches for moulds, bacteria, and viruses. Limited fresh air exchange can compound the problem by circulating contaminated air through living quarters and workspaces.
Traditional mitigation strategies often rely on reactive measures such as intermittent cleaning or odour masking. While these may mask the problem, these superficial fixes fail to address underlying microbial proliferation. It risks recurrent contamination, persistent odours, and ongoing health hazards for crews, undermining long-term operational reliability. The key question is: how can we manage IAQ more effectively at its source?

Natural, proven antimicrobial treatment as part of a smarter strategy

Recent studies, including research from Griffith University, show that controlled release of tea tree oil vapours in HVAC systems can dramatically reduce airborne microbes while disinfecting the air duct system.  Results found over 70% reduction in microbial aerosols within 24 hours, reaching more than 97% after a week.  
Unlike harsh chemicals, tea tree oil is naturally antibacterial, antifungal, and antiviral. It provides sustained action without leaving behind toxic residues or harmful byproducts. While not a silver bullet for all IAQ challenges, it’s a strong case for rethinking the way microbial control is approached onboard.

What this means for marine operators

For chief engineers, captains, and operators, IAQ should be seen as a critical safety factor. This means:

• Recognizing microbial build-up in HVAC systems as a predictable hazard, not an unavoidable nuisance.
• Moving from reactive fixes (masking odours, occasional cleaning) to continuous, proactive microbial management.
• Considering natural, sustainable antimicrobial methods alongside regular maintenance and ventilation upgrades.
• Understanding how healthier air supports crew wellbeing, operational efficiency, and compliance with Marine Labour Convention. 

Indoor air quality onboard ships may be invisible, but its impact is undeniable. By moving beyond temporary fixes and adopting evidence-based, natural antimicrobial methods, marine operators can create healthier environments, safeguard crew welfare, and strengthen vessel resilience.