A team from Nanjing University have examined evidence from a number of scientific disciplines which, they say, suggests that the microscopic plastic fragments we are breathing in on a daily basis could serve as vehicles for viruses such as influenza and COVID-19.
While microplastics are defined as particles smaller than 5 mm, nanoplastics are smaller than one micron and have been detected everywhere from urban centres to polar ice, deserts and stratospheric air samples.
It has been estimated that indoor air contains around 528 nanoplastic particles per cubic metre, meaning adults are likely to be inhaling tens of thousands of these particles each day.
While previous research has focused on the toxic effects of these plastics on immune, reproductive and cardiovascular systems, their potential role in spreading infectious diseases has received little attention until now.
The size and surface properties of airborne microplastics make them, in theory, ideal viral carriers. Most detected airborne plastics are smaller than 100 micrometers, with many fine particles capable of penetrating deep into the respiratory tract. This size range closely matches that of human viruses, which span from 20 to 100 nanometers, facilitating stable viral attachment to plastic surfaces.
What makes microplastics particularly concerning is their persistence. Unlike other airborne particles, plastics have relatively low density, allowing them to remain suspended in the air for extended periods and disperse more widely. Their carbon-rich surfaces can also harbour bacteria and fungi that might shield attached viruses from ultraviolet radiation, desiccation and disinfectants.
Laboratory evidence supports these concerns. Research shows that SARS-CoV-2, the virus responsible for COVID-19, can remain viable on plastic surfaces for more than a week. Studies on particulate matter have demonstrated that influenza viruses can bind to airborne particles and remain infectious.
Lead author Mengjie Wu said: ‘People often think of microplastics as an ocean problem but we are breathing them in every day, and their interactions with microbes and viruses could be far more complex than we imagine.’
Senior author Huan Zhong said: ‘Whether these particles truly act as vectors is still unproven but the evidence is strong enough that we can no longer ignore the possibility,’ adding, ‘This is a frontier that connects environmental science and infectious disease. Understanding it will be critical for protecting both planetary and human health.’
The team observe that some questions remain unanswered: How many viable viruses can attach to airborne microplastics? Under what environmental conditions do they remain infectious? And, perhaps most importantly, what concentration of virus-laden plastics would constitute a meaningful health risk?
The researchers are calling for urgent, coordinated studies integrating expertise from ecotoxicology, microbiology, and atmospheric science. If this transmission pathway is confirmed, it would have far-reaching implications for public health policy, particularly in urban and indoor environments where microplastic concentrations are highest.
Photo: Fusion Medical Animation / Unsplash
Leave a Reply