How Clean Is The Air On Your MRT Train?

Airborne threats can be detected by sampling aerosols in public spaces, say researchers from Singapore.

AsianScientist (Dec. 14, 2018) – In a study published in Scientific Reports, a research group in Singapore has sampled aerosols in public spaces for disease surveillance.

Detection and monitoring are essential to the containment of airborne infectious threats, such as the viruses that cause severe acute respiratory syndrome, avian influenza and Middle East respiratory syndrome. However, testing large numbers of individuals is costly and difficult to implement.

In the present study, researchers at the Duke-National University of Singapore (NUS) Medical School used a bioaerosol sampling method, coupled with molecular diagnostics, to non-invasively collect and identify three respiratory viruses of public health importance. This is especially relevant to densely-populated countries like Singapore, which face a heightened risk of disease outbreaks as a global trade and tourism hub.

The study was conducted over a period of one year and involved the researchers collecting aerosol samples during peak ridership hours on Singapore’s Mass Rapid Transit (MRT) system. To do this, the researchers used National Institute for Occupational Safety and Health aerosol samplers attached to personal backpacks carrying air pumps.

Air was sampled from frequently used MRT lines. Molecular analyses revealed that some of the collected samples tested positive for adenovirus, influenza A virus and respiratory syncytial virus type A.

“Usually, transit network studies focus on mapping surface-borne bacterial DNA and neglect to target aerosolized or respiratory-borne RNA viruses. Our study demonstrates that bioaerosol sampling might have a practical application for the detection of respiratory pathogens in crowded public areas, such as transportation systems,” said Dr. Gregory Gray, a professor of the Duke-NUS emerging infectious diseases signature research program and senior author of the study.

“This is important in terms of pandemic preparedness, as a bioaerosol sampling system does not require the timely acquisition of ethical approvals and informed consent needed to collect individual samples from human subjects,” he added.

The findings support the possibility of employing bioaerosol samplers in crowded places to monitor respiratory viruses that could be circulating. In the event of a suspected or ongoing disease outbreak, such samplers could be immediately deployed in high-risk areas, yielding results within approximately eight hours. Proactive monitoring for respiratory viruses would also eliminate the risk of missing the time frame of exposure to pandemic viruses in high-risk areas, as well as enable more robust disease surveillance.

The study authors cautioned that more research is needed before bioaerosol sampling can be deployed to safeguard public health. Nonetheless, they are hopeful their findings will advance not only the science but also the technology to improve bioaerosol sampling techniques.

“MRT riders may be at a higher risk of exposure to respiratory viruses. We certainly hope this Duke-NUS study will motivate scientists across the globe to collaborate on similar field studies to unveil the true risk of exposure while using public transportation, as data on this topic are scarce,” said Gray.

The article can be found at: Coleman et al. (2018) Bioaerosol Sampling for Respiratory Viruses in Singapore’s Mass Rapid Transit Network.


Source: National University of Singapore; Photo: Pixabay.
Disclaimer: This article does not necessarily reflect the views of AsianScientist or its staff.

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