People are more likely to catch Covid-19 in areas with bad air pollution because particles can ‘carry’ the virus, scientists have claimed.
Now, international researchers led by Taipei Medical University in Taiwan have claimed pollution plays a ‘direct role’ in the spread of the disease.
Viruses may be absorbed by particulate matter – produced mostly by car fumes and construction work – and then travel or linger in the air for hours or even days before being inhaled by someone, they said.
This would suggest the coronavirus is airborne, meaning people can inhale it from tiny particles in the air.
Moreover, evidence suggests particulate matter may make the cells in the lungs more susceptible to the coronavirus, increasing the risk of someone becoming badly affected.
People are more likely to catch Covid-19 in areas with high air pollution because particles ‘carry’ the virus, scientists have claimed. (Pictured: A woman wearing a mask in London)
A team led by Nguyen Thanh Tung, of Taipei Medical University, Taiwan, drew on various pieces of research to support their theory, published in the journal Science of The Total Environment.
Until now, health officials have said the coronavirus is spread mainly from large respiratory droplets expelled from coughing or sneezing.
But emerging evidence suggests airborne transmission also plays a role.
The scientists said viruses may be absorbed by particulate matter (PM) and remain ‘airborne for hours or days’.
The tiny particles can then be inhaled deep into the lungs where the virus begins replicating.
WHAT IS PARTICULATE MATTER (PM)?
PM is a mixture of solid particles and liquid droplets found in the air.
They are created from a variety of sources including traffic, construction sites, unpaved roads, fields, smokestacks or fires.
Most particles form in the atmosphere as a result of reactions of chemicals such as sulphur dioxide and nitrogen oxides.
Some PM, such as dust, dirt, soot, or smoke, is large or dark enough to be seen with the naked eye.
Other PM is so small it can only be detected using an electron microscope.
PM2.5 – of diameters that are generally 2.5 micrometers and smaller – differ from PM10 – 10 micrometers and smaller.
Source: US EPA
PM may provide ‘a good platform to shade and carry the SARS-CoV-2’ and be a ‘direct transmission model in a highly polluted area’, the paper claimed.
There are some studies which support this theory to some extent.
Italian researchers showed how genetic material of SARS-CoV-2 was detectable in 19 of 34 PM samples in Bergamo, Italy.
Various studies in Italy have shown places that have been the hardest hit by Covid-19 also have significant pollution.
Lombardi and Emilia Romagna in northern Italy have a lot of factories, heavy traffic and are surrounded by mountains which prevent air flow.
It’s been reported both locations also have a higher Covid-19 mortality rate than other places in Italy. However, there could be many other underlying reasons other than pollution.
In another study spanning 120 cities in China, research showed that every increase of 10 micrograms per cubic meter in concentration of PM2.5 led to more than a two per cent increase in new Covid-19 cases.
PM2.5, which is mainly produced by traffic fumes, industry and household heating, are tiny particles finer than a human hair.
But it was later argued that this rise in Covid-19 infection was because of the crowded cities rather than the exposure to air pollution.
It wouldn’t be the first time a virus has latched on to toxic air as a means of surviving – bird flu and seasonal influenza have both been discovered in PM.
Mr Tung and colleagues explained that the PM may make the lungs more susceptible to the coronavirus by increasing the expression of ACE-2 receptors that coat cells.
ACE-2 receptors are used as a ‘gateway’ for SARS-CoV-2 to enter cells. Therefore, a person who inhales polluted air may have more entry points for the coronavirus.
Previous work by the team has shown that three months of exposure to PM increase ACE-2 expression in the rat lungs.
They concluded in their paper: ‘The combination of PM and SARS-CoV-2 may aggravate lung injury by increasing inflammation. Herein, providing insights into the risk of airborne transmission of SARS-CoV-2 via PM.’
But as of yet, it has been difficult to prove that if someone has more ACE-2 expression, they are at higher risk of catching Covid-19.
In fact, some researchers say that ACE-2 is preventative of severe lung damage.
Air pollution affects all regions of the world, but more so in low-income cities, 97 per cent of which do not meet air quality guidelines set out by the World Health Organization (WHO).
Even in high-income countries, 49 per cent are breaching pollution limits.
There are particularly high exposures in the Eastern Mediterranean, South‐East Asian and Western Pacific regions.
However, it is the US, Europe and Latin America which has been significantly impacted by Covid-19, if looking at government reported data on cases and deaths.
Particulate matter is in the air pollution emitted from vehicles, factories, construction sites, tilled fields, unpaved roads, and burning of fossil fuels.
It’s been shown in years of scientific research to amage airways, leading to breathing difficulties and the development of asthma in children who are genetically at risk.
WHAT HAVE RECENT STUDIES SHOWN POLLUTION CAN DO TO OUR HEALTH AND BODIES?
CAUSE CHILDREN TO HAVE A LOW IQ: Researchers at the University of California, San Francisco, found in May 2019 that children born to mothers who live in polluted areas have an IQ that is up to seven points lower than those living in places with cleaner air.
CAUSE CHILDREN TO HAVE POORER MEMORY: Researchers at the Barcelona Institute for Global Health found boys exposed to greater levels of PM2.5 in the womb performed worse on memory tests by the time they are 10.
DELAY THE DEVELOPMENT OF CHILDREN: Youngsters who live less than one-third of a mile away from busy roads are twice as likely to score lower on tests of communication skills in infancy, found researchers at Eunice Kennedy Shriver National Institute of Child Health in April. They were also more likely to have poorer hand-eye coordination.
MAKE CHILDREN MORE ANXIOUS: University of Cincinnati scientists claimed pollution may alter the structure of children’s brains to make them more anxious. Their study of 14 youngsters found rates of anxiety was higher among those exposed to greater levels of pollution.
CUT YOUR CHILD’S LIFE SHORT: Children born today will lose nearly two years of their lives because of air pollution, according to a report by the US-based Health Effects Institute and the University of British Columbia in April 2019. UNICEF called for action on the back of the study.
RAISE A CHILD’S RISK OF AUTISM: Researchers at Monash University in Australia discovered youngsters living in highly polluted parts of Shanghai have a 86 per cent greater chance of developing ASD. Lead author Dr Yuming Guo said: ‘The developing brains of young children are more vulnerable to toxic exposures in the environment.’
CAUSE ASTHMA IN CHILDREN: Four million children around the world develop asthma each year because of road traffic pollution, a major study by academics at George Washington University estimated. Experts are divided as to what causes asthma – but exposure to pollution in childhood increases the risk by damaging the lungs.
MAKE CHILDREN FAT: University of Southern California experts found last November that 10 year olds who lived in polluted areas when they were babies are, on average, 2.2lbs (1kg), heavier than those who grew up around cleaner air. Nitrogen dioxide pollution could disrupt how well children burn fat, the scientists said.
LEAVE WOMEN INFERTILE EARLIER: Scientists at the University of Modena, Italy, claimed in May 2019 that they believe pollution speeds up ageing in women, just like smoking, meaning they run out of eggs faster. This was based on them finding almost two-thirds of women who have a low ‘reserve’ of eggs regularly inhaled toxic air.
RAISE THE RISK OF A MISCARRIAGE: University of Utah scientists found in January that pregnant women are 16 per cent more likely to suffer the heartbreak of a miscarriage if they live in areas of high pollution.
RAISE THE RISK OF BREAST CANCER: Scientists at the University of Stirling found six women working at the same bridge next to a busy road in the US got breast cancer within three years of each other. There was a one in 10,000 chance the cases were a coincidence, the study said. It suggested chemicals in the traffic fumes caused the cancer by shutting down the BRCA genes, which try to stop tumours growing.
DAMAGE A MAN’S SPERM: Brazilian scientists at the University of Sao Paulo found in March that mice exposed to toxic air had lower counts and worse quality sperm compared to those who had inhaled clean air since birth.
MAKE MEN LESS LIKELY TO GET SEXUALLY AROUSED: Scientists at Guangzhou Medical University in China found rats exposed to air pollution struggled to get sexually aroused. Scientists believe it may also affect men, as inhaling poisonous particles may trigger inflammation in blood vessels and starve the genitals of oxygen – affecting men’s ability to become sexually aroused.
MAKE MEN MORE LIKELY TO HAVE ERECTILE DYSFUNCTION: Men who live on main roads are more likely to have difficulty getting an erection due to exposure to pollution, a Guangzhou University in China study suggested in February. Toxic fumes reduced blood flow to the genitals, tests on rats showed, putting them at risk of developing erectile dysfunction.
RAISE THE RISK OF PSYCHOSIS: In March, King’s College London scientists linked toxic air to intense paranoia and hearing voices in young people for the first time. They said uncovering exactly how pollution may lead to psychosis should be an ‘urgent health priority’.
MAKE YOU DEPRESSED: Massachusetts Institute of Technology researchers found in January that that the more polluted the air, the sadder we are. Their study was based on analysing social media users in China alongside the average daily PM2.5 concentration and weather data where they lived.
CAUSE DEMENTIA: Air pollution could be responsible for 60,000 cases of dementia in the UK, researchers from King’s College London and St George’s, University of London, calculated last September. Tiny pollutants breathed deep into the lungs and enter the blood stream, where they may travel into the brain and cause inflammation – a problem which may trigger dementia.