Smoking and dirty air increase the risk of chronic illnesses that leave patients more vulnerable to COVID-19, such as heart disease, asthma and lung cancer.
Image: picture-alliance/Photoshot/P. Sarkar
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Two main risk factors are currently known to raise the chance of dying from the novel coronavirus that has brought the world to a halt: being old and having a weak immune system.
Air pollution makes the second of those more likely.
"If you live in a polluted area, your lungs are compromised like somebody who smokes, so you're more susceptible to the coronavirus," said Kofi Amegah, an epidemiologist and air pollution expert at the University of Cape Coast in Ghana.
Dirty air, which claims more than 7 million lives a year, could make COVID-19 more deadly by contributing to chronic health conditions that leave patients weak in the face of infection.
The European Public Health Alliance said last week that air pollution is likely to cut survival chances from COVID-19.
Research on previous outbreaks has also suggested bad air makes viruses more deadly and spread further. A study of SARS-CoV-1 victims in 2003 found that patients were twice as likely to die in regions where air pollution was high rather than low. Even in regions that were only moderately polluted, the risk of dying was 84% higher.
If a similar dynamic exists for COVID-19, it could add pressure on the critical care units of hospitals in smoggy cities with rapidly rising cases, such as Madrid, London and New York. It could also spell trouble for countries in the global south where most people burn wood, dung, kerosene or coal indoors to cook and heat their homes.
Hospitals in northern Italy have been overwhelmed, forcing doctors to choose between patients to saveImage: picture-alliance/dpa/AP/LaPresse/C. Furlan
Masks to prevent pollution may also help reduce the spread of coronavirusImage: picture-alliance/AA/F. Bahrami
Silent killer
In northern Italy and the Chinese city of Wuhan, home to high levels of pollution and some of the most severe outbreaks to date, preliminary data suggests that particulate matter may already have played a role in overwhelming health care systems.
PM2.5 — particulate matter smaller than 2.5 microns in diameter, less than the width of a human hair — can penetrate the lung barrier and enter the bloodstream, raising the risk of developing heart and lung disease.
The case fatality rate in China was nine times higher for people with cardiovascular disease and six times higher for patients with diabetes, hypertension and respiratory disease than it was for people without underlying health conditions, a joint study by the World Health Organization and China found in February.
In Italy, health officials reported in March that 99% of a sample of patients who died from COVID-19 had an underlying illness — with almost half the deceased having suffered from three or more — though the sample was not drawn randomly and may not represent the population. The most common ailments were high blood pressure, heart disease and diabetes.
The WHO says the pandemic is too recent to draw a link between air pollution and the deadliness of COVID-19, but this shouldn't stop countries from acting.
"Whether or not we have this correlation between COVID-19 and air pollution, we need to reduce air pollution no matter what," Maria Neira, director of public and environmental health at the World Health Organization, told DW.
"Stop smoking and reduce the levels of air pollution — that is a recommendation we can make even without having more evidence."
Vatican City nestled in the heart of Rome has stood empty like the rest of the country for weeksImage: Imago Images/Zuma/E. Inetti
Venice, too, has become a ghost townImage: picture-alliance/dpa/AP/LaPresse/A. Marinoni
Together with ozone pollution, PM2.5 particles shave almost three years off our lives, a study in the journal Cardiovascular Research found last month. The global loss of life from outdoor air pollution is 10 times greater than that of all forms of violence put together.
Moreover, about nine in 10 premature deaths caused by air pollution — including toxic gases NO2 and SO2 — hit people in low and middle-income countries. Even within rich cities in Europe and North America, working class, black and ethnic minority communities tend to breathe the dirtiest air.
Across sub-Saharan Africa, women are particularly exposed to pollutants from indoor cooking.
"For these women, their lung systems are compromised," said Amegah from Ghana's University of Cape Coast, adding that if COVID-19 spreads they will be especially vulnerable.
"We pray and keep our fingers crossed we don't see the levels [we're seeing] in northern Italy and China."
As well as weakening the body, airborne pollutants could even act as a carrier of the new coronavirus and allow it to survive in the air attached to particulates, a team of Italian researchers suggested in March.
High concentrations of particulate matter in parts of northern Italy in February may have "boosted" the spread of the epidemic this way, according to a position paper published by the Italian Society of Environmental Medicine that has not yet been peer-reviewed.
Other scientists have cast doubt on this, pointing out that there are no reported cases of this coronavirus spreading in the air and that people are the main vector of transmission.
"It's good to reduce air pollution to promote health, even to help decrease preconditions that could aggravate coronavirus, such as asthma, but I cannot see [air pollution] as an important contribution to the discussion about containment of the virus," said Jos Lelieveld, director of atmospheric chemistry at the Max Planck Institute and lead author of the study on deaths from air pollution.
As coronavirus cases rise exponentially around the world, lockdowns to stop its spread have reduced pollution levels.
Fossil fuel use has decreased as lockdowns have grounded planes, shuttered factories and kept cars off the streetsImage: picture-alliance/SvenSimon/F. Hoemann
The toxic pollutant NO2 has dropped because of coronavirus lockdownsImage: picture-alliance/dpa/NASA
Satellite images of China and Italy show striking drops in NO2, a toxic gas that inflames the airways, as governments closed factories and kept cars off the streets. The drop in air pollution in China may even have saved more lives than were lost from COVID-19, a study that has not yet been peer-reviewed suggested on Friday, though this comparison does not factor in the lives that would have been lost had the coronavirus spread unchecked.
Not all of the fall in air pollution seen from space can be attributed to lockdowns, either. Air pollution is higher in colder months anyway because people heat more and drive cars more often, so it tends to fall around this time of year, said Christian Retscher of the European Space Agency.
"Certainly, we see an effect of the coronavirus on NO2 … We see an additional effect [but] we don't know the precise number."
While lockdowns have helped clean the air, it is also uncertain how long they will keep pollution levels down.
"Once the crisis is over, and we see this in China, there's a temptation to compensate for the weeks and months lost," said Zoltan Massay-Kosubek, a policy expert for clean air and sustainable transport at the European Public Health Alliance.
Nonetheless, this shows that air pollution can be reduced and lives saved, said the WHO's Neira. "Now we need to maintain that — not the fact that we'll be confined, but reducing the air pollution levels outside."
Coronavirus: Timeline of the global spread of COVID-19
Since the first cases were confirmed in December 2019, the flu-like COVID-19 virus exploded into a global pandemic, killing tens of thousands of people and infecting around 800,000. Scientists scramble for a vaccine.
Image: picture-alliance/dpa/SOPA Images/A. Marzo
Pneumonia-like virus hits Wuhan
On December 31, 2019, China notifies the World Health Organization of a string of respiratory infections in the city of Wuhan, home to some 11 million people. The root virus is unknown and disease experts around the world begin working to identify it. The strain is traced to a seafood market in the city, which is quickly shut down. Some 40 people are initially reported to be infected.
Image: Imago Images/UPI Photo/S. Shaver
First death in China
On January 11, China announces the first death from the coronavirus — a 61-year-old man, who had shopped at the Wuhan market, dies from complications with pneumonia. Like SARS and the common cold, scientists identified that the new virus is in the coronavirus family. It is temporarily named 2019-nCoV. Symptoms include fever, coughing, difficulty breathing, and pneumonia.
Image: Reuters/Str
Virus reaches neighboring countries
In the following days, countries such as Thailand and Japan begin to report cases of infections in people who had visited the same Wuhan market. In China, a second fatality is confirmed in the city. By January 20, three people have died in China and more than 200 are infected.
Image: Reuters/Kim Kyung-Hoon
Millions under lockdown
China places Wuhan on quarantine on January 23 in an attempt to limit the spread of the virus. Transportation is suspended and workers attempt to quickly build a new hospital to treat infected patients, which total over 830 by January 24, as the death toll climbs to 26. Officials eventually extend the lockdown to 13 other cities, affecting at least 36 million people.
Image: AFP/STR
A global health emergency?
More and more cases are confirmed outside of China, including in South Korea, the US, Nepal, Thailand, Hong Kong, Singapore, Malaysia and Taiwan. As the number of infections rises, the World Health Organization on January 23 determines that it's "too early" to declare a global public health emergency.
Image: Getty Images/X. Chu
Coronavirus reaches Europe
On January 24, French authorities confirm three cases of the new coronavirus within its borders, marking the disease's first appearance in Europe. Hours later, Australia confirms four people have been infected with the respiratory virus.
Image: picture-alliance/dpa/S. Mortagne
First cases confirmed in Germany
On January 27, Germany announces its first known case of the virus — a 33-year-old in Bavaria who contracted it during a workplace training with a visiting Chinese colleague. He is put under quarantine and observation at a Munich hospital. The following day, three of his colleagues are confirmed infected. The death toll in China reaches 132, with around 6,000 infected worldwide.
Image: Reuters/A. Uyanik
WHO declares global health emergency
On January 30, the UN's World Health Organization (WHO) declares coronavirus a public health emergency of international concern in a bid to protect countries with "weaker health systems." However, WHO Secretary-General Tedros Adhanom Ghebreyesus does not recommend trade and travel restrictions, saying these would be "an unnecessary disruption."
Image: picture-alliance/KEYSTONE/J.-C. Bott
First death outside China
The first death linked to the novel coronavirus outside of China is reported in the Philippines on February 2. A 44-year-old Chinese man had traveled from Wuhan to Manila before falling ill and being taken to hospital, where he later died of pneumonia.
Image: Getty Images/AFP/T. Aljibe
Bad ending to a cruise
Also on February 3, the cruise ship Diamond Princess is quarantined off Yokohama in Japan after cases of the new coronavirus were found on board. As of February 17, the number of people infected has grown to more than 450, the largest cluster of cases outside of China. Several of the 3,700 passengers and crew onboard the ship are being or have been flown back to their home countries.
Image: picture-alliance/dpa/kyodo
Italy under quarantine
Cases in Italy rise dramatically, with 77 deaths and thousands of confirmed cases by March 3. Many countries instigate travel restrictions to northern Italy and tourist numbers plummet. On March 8, the Italian government put the entire Lombardy region into quarantine, affecting 16 million people. March 10 sees 168 fatalities in Italy, the highest in a single day.
Image: Reuters/R. Casilli
Economic woes
European and US stock markets slump on March 6, leading to the worst week since the 2008 financial crisis. The effect on global business has been significant, with many companies reporting losses and the tourism industry and airlines badly hit. The EU pledge €7.5 billion ($8.4 billion) on March 10 in an investment fund to try to stop the Eurozone falling into a recession.
Image: picture-alliance/Jiji Press/M. Taguchi
WHO declares outbreak as pandemic
As worldwide cases top 127,000 and deaths pass 4,700, the World Health Organization designates the global outbreak as a "pandemic" on March 11. US President Donald Trump announces a travel restriction on people coming from the Schengen Zone in Europe, annoying the EU. German Chancellor Angela Merkel announces that in Germany, 70% of the population could get the virus.
Image: picture-alliance/Photoshot
Public life on hold in Europe
On March 14, Spain joins Italy in imposing a near-total nationwide lockdown to prevent the virus spreading. The population of 46 million is told not to leave their homes unless for essential tasks. In France, cafés, restaurants and non-essential shops are closed as of March 15. Many public events in Germany are cancelled and schools close.
Image: picture-alliance/dpa/AAB. Akbulut
International travel severely restricted
As of March 15, many countries impose strict travel bans or restrictions in an attempt to stop the spread of Covid-19. For example, New Zealand and Australia require all international passengers to self-isolate for 14 days after arrival in the country. The US extends a European travel ban to include the United Kingdom and Ireland.
Image: picture-alliance/Photoshot
Germany imposes partial lockdown
In a landmark televised address German Chancellor Angela Merkel announces far-reaching restrictions on everyday life on March 22, banning meetings between more than two people not from the same household outside of the workplace. The country has a surprisingly low death rate, a phenomenon attributed to a high level of testing, and a high number of intensive care beds.
Image: picture-alliance/EibnerT. Hahn
Virus strikes at top as UK locks down
On March 23rd Britain becomes the latest country to impose restrictions on personal freedoms, with people only allowed to leave their homes in a limited number of circumstances. Prime Minister Boris Johnson is diagnosed with the viruson March 27, as well as heir to the throne Prince Charles on March 25. Meanwhile, there are complaints that not everyone is taking social distancing seriously.
Image: picture-alliance/R. Pinney
Grim milestone for the US
On March 27 the US overtakes China in terms of the number of people infected, making it the country with the most cases of COVID-19. This came as President Donald Trump claimed that the nation would get back to work "pretty quickly." At the same time, it emerged that more than 3 million Americans had lost their jobs due to the pandemic. New York is worst-hit, with a hospital ship sent to help out.
Image: picture-alliance/Photoshot/J. Fischer
Spain's surging death toll
Spain also overtakes China in the number of COVID-19 cases on March 30, as the government toughens the severity of its lockdown. All non-essential activities are halted. Only Italy has a higher death toll than Spain. Most affected is the capital, Madrid. With funeral services overwhelmed, officials turn the Palacio de Hielo ice skating rink into a temporary morgue.
Image: picture-alliance/Geisler-Fotopress
More than a million
On April 2nd the Johns Hopkins University announced on Thursday that there were more than a million confirmed coronavirus cases around the world. The US is the most affected with three times the number than China, where the virus emerged in December. Over 50.000 people have died — and the outlook remains grim.
Image: Reuters/J. Redmond
UK PM Boris Johnson hospitalized
The 55-year-old was admitted to the intensive care unit at London's St Thomas hospital on Monday evening (6.4.) and was given oxygen treatment after his condition worsened. He had been diagnosed with COVID-19 on March 27.
