https://www.theguardian.com/environment/2020/apr/24/coronavirus-detected-particles-air-pollution
Coronavirus detected on particles of air pollution
Exclusive: Scientists examine whether this route enables infections at longer distances
Coronavirus has been detected on particles of air pollution by scientists investigating whether this could enable it to be carried over longer distances and increase the number of people infected.
The work is preliminary and it is not yet known if the virus remains viable on pollution particles and in sufficient quantity to cause disease.
The Italian scientists used standard techniques to collect outdoor air pollution samples at one urban and one industrial site in Bergamo province and identified a gene highly specific to Covid-19 in multiple samples. The detection was confirmed by blind testing at an independent laboratory.
Leonardo Setti at the University of Bologna in Italy, who led the work, said it was important to investigate if the virus could be carried more widely by air pollution.
“I am a scientist and I am worried when I don’t know,” he said. “If we know, we can find a solution. But if we don’t know, we can only suffer the consequences.”
Two other research groups have suggested air pollution particles could help coronavirus travel further in the air.
A statistical analysis by Setti’s team suggests higher levels of particle pollution could explain higher rates of infection in parts of northern Italy before a lockdown was imposed, an idea supported by another preliminary analysis. The region is one of the most polluted in Europe.
Neither of the studies by Setti’s team have been peer-reviewed and therefore have not been endorsed by independent scientists. But experts agree their proposal is plausible and requires investigation.
Previous studies have shown that air pollution particles do harbour microbes and that pollution is likely to have carried the viruses causing bird flu, measles and foot-and-mouth disease over considerable distances.
The potential role of air pollution particles is linked to the broader question of how the coronavirus is transmitted. Large virus-laden droplets from infected people’s coughs and sneezes fall to the ground within a metre or two. But much smaller droplets, less than 5 microns in diameter, can remain in the air for minutes to hours and travel further.
Experts are not sure whether these tiny airborne droplets can cause coronavirus infections, though they know the 2003 Sars coronavirus was spread in the air and that the new virus can remain viable for hours in tiny droplets.
But researchers say the importance of potential airborne transmission, and the possible boosting role of pollution particles, mean it must not be ruled out without evidence.
Quick guide
Will there be a second wave of coronavirus?
Prof Jonathan Reid at Bristol University in the UK is researching airborne transmission of coronavirus. “It is perhaps not surprising that while suspended in air, the small droplets could combine with background urban particles and be carried around.”
He said the virus had been detected in tiny droplets collected indoors in China.
Setti said tiny droplets between 0.1 and 1 micron may travel further when coalesced with pollution particles up to 10 microns than on their own. This is because the combined particle is larger and less dense than the droplet and can remain buoyed by the air for longer.
“The pollution particle is like a micro-airplane and the passengers are the droplets,” said Sett. Reid is more cautious: “I think the very small change in the size of the [combined] particles is unlikely to play much of a role.”
Prof Frank Kelly at Imperial College London said the idea of pollution particles carrying the virus further afield was an interesting one. “It is possible, but I would like to see this work repeated by two or three groups.”
Share your story
Share your experiences
If you would like to share your stories about testing you can get in touch by filling in the form below. Only the Guardian can see your contributions and one of our journalists may contact you to discuss further.
Share your story
Share your experiences
If you would like to share your stories about testing you can get in touch by filling in the form below. Only the Guardian can see your contributions and one of our journalists may contact you to discuss further.
Another expert, Prof John Sodeau at University College Cork, in the Republic of Ireland, said: “The work seems plausible. But that is the bottom line at the moment, and plausible [particle] interactions are not always biologically viable and may have no effect in the atmosphere.” He said the normal course of scientific research might take two or three years to confirm such findings.
Other research has indicated correlations between increased Covid-19 deaths and higher levels of air pollution before the pandemic. Long-term exposure to dirty air is known to damage lung health, which could make people more vulnerable to Covid-19.
News is under threat …
… just when we need it the most. Millions of readers around the world are flocking to the Guardian in search of honest, authoritative, fact-based reporting that can help them understand the biggest challenge we have faced in our lifetime. But at this crucial moment, news organisations are facing an unprecedented existential challenge. As businesses everywhere feel the pinch, the advertising revenue that has long helped sustain our journalism continues to plummet. We need your help to fill the gap.
We believe every one of us deserves equal access to vital public service journalism. So, unlike many others, we made a different choice: to keep Guardian journalism open for all, regardless of where they live or what they can afford to pay. This would not be possible without financial contributions from those who can afford to pay, who now support our work from 180 countries around the world.
We have upheld our editorial independence in the face of the disintegration of traditional media – with social platforms giving rise to misinformation, the seemingly unstoppable rise of big tech and independent voices being squashed by commercial ownership. The Guardian’s independence means we can set our own agenda and voice our own opinions. Our journalism is free from commercial and political bias – never influenced by billionaire owners or shareholders. This makes us different. It means we can challenge the powerful without fear and give a voice to those less heard.
Reader financial support has meant we can keep investigating, disentangling and interrogating. It has protected our independence, which has never been so critical. We are so grateful.
We need your support so we can keep delivering quality journalism that’s open and independent. And that is here for the long term. Every reader contribution, however big or small, is so valuable. Support the Guardian from as little as $1 – and it only takes a minute. Thank you.
沒有留言:
張貼留言