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Coronavirus and air pollution, a dangerous liaison

Much has been said and written about the relationship between coronavirus and air pollution, as well as air quality. Our analysis sorts the facts from opinions.

Satellite images leave no room for doubt. The lockdown and imposed isolation following the spread of the coronavirus pandemic has had a single desirable effect: a noticeable decrease in smog, first in China then in Italy. In particular, the shutdown in the Po Valley, one of Europe’s most polluted areas, has made the decline of some pollutants visible “to the naked eye”. Among these is nitrogen dioxide (NO2), which causes the premature death of 14,600 people every year in Italy alone, a significant proportion of the country’s 76,200 total deaths due to pollution and particulate emissions, as estimated by the European Environment Agency.

Satellites show a smog-free Po Valley

As predicted by NASA and ESA, and confirmed by the EU’s atmospheric monitoring service Copernicus, the effect of Covid-19 on air quality in Lombardy has resulted in a 10 per cent decrease in the concentration of atmospheric NO2 per week over the last month. In Milan, “average NO2 concentrations were around 65 microgrammes (μg) per square metre in January, 50 μg per square metre in February and less than 40 μg per square metre in the first half of March”.

Similar trends have been occurring in other cities in Northern Italy, such as Turin and Bergamo. In Bologna, concentrations were around 30 μg per square metre in January, and since the beginning of February they’ve reached an average of around 15 μg. “Nitrogen dioxide is a short-lived pollutant,” experts from Copernicus state, “once emitted, it stays in the atmosphere generally less than a day before being deposited or reacting with other gases in the atmosphere”.


Coronavirus and air pollution, a lockdown isn’t enough

Italian and European experts note that the data should be interpreted accurately across time as well, not just in the short term. “The concentration of pollutants is variable and can be affected by wind and weather. These variations make it difficult to determine and distinguish trends in the short term”. Specialists from Lombardy’s Regional Environmental Protection Agency (ARPA) also caution against making rushed judgements on these trends: “We can’t simply compare the situation over the past three weeks with last year, or even with the previous three weeks”.

In fact, experts at Copernicus note that “as a paradox, until a complete lockdown is decided, emissions from some sectors may increase in such a situation”. For example, they mention increased use of cars by people who opt against public transport for fear of contagion, as well as a rise in residential heating with more people working from home. Therefore, a real evaluation of the phenomenon will only be possible at a later stage, when definitive figures on traffic, industry and energy demand are available.

Air pollution is also affected by weather

Stefano Caserini, an environmental engineer and climate change expert, has set out a series of reflections on the effect of coronavirus in the fight against smog and global warming. “After China saw an estimated reduction of CO2 emissions amounting to around 200 million tonnes linked to the decrease in coal use in the industrial sector, a similar trend is expected in Italy. Emissions of CO2 and other pollutants are likely to fall due to lower traffic levels in many cities, reduced travel and limited production rates in many areas”.

Yet Caserini warns us to be cautious. “Air pollution doesn’t depend solely on emissions. In fact, weather is a key factor affecting concentrations of pollutants and in some areas, like the Po Valley, it plays a crucial role. For example, reductions in concentrations of PM10 and NO2 recorded in Lombardy on the 26th and 27th February of were tied to a significant episode of Foehn wind. This had a much more significant effect on air quality compared to the reduction of traffic linked with the coronavirus shutdown,” the climatologist explains.

Environmental and epidemiological predictions should be handled with care

It will take time to carry out complete evaluations both in terms of environmental policy and public health based on the data collated by experts. This is all the more true with regards to epidemiological data on the coronavirus pandemic. Epidemiologist Fabrizio Bianchi, director of the Institute of Clinical Physiology (IFC) at the Italian National Research Council in Pisa, reminds us that there are no definitive estimates of how many people have contracted the illness, only projections. Therefore, at the moment the virus’s lethality can’t be determined with any certainty. Regardless of statistics, we’re just going to have to wait.

People are still getting ill because of air pollution

However, one thing that is sadly certain is that people become ill and die due to air pollution just as they do because of SARS-CoV-2. Anna Gerometta, president of Cittadini per l’Aria (Citizens for Air) – an organisation that has for years fought for robust policies to improve air quality – reminds us that Lombardy and the Po Valley’s residents are paying an extremely high price, with loss of life on both counts. Might the two phenomena be related? “From the start of December to the first week of February 2020, concentrations of PM10, PM2.5 and NO2 in Lombardy were well above legal limits,” Gerometta states. EU regulations indicate a maximum of 35 days a year in which PM10 concentration can surpass 50 µg per square metre; in Lombardy, this threshold had been reached by mid-February. “This has led to an increase in children and adults seeking emergency medical assistance due to the rise in respiratory illnesses,” Gerometta reiterates. “Our hope is that the healthcare emergency triggered by coronavirus will bring a change to environmental policy in the region”.


WHO: air pollution causes 7 million deaths a year

“In Italy, and especially in Northern Italy, chronic and acute respiratory diseases are constantly increasing, in direct correspondence with the amount of particulates people are exposed to,” pulmonologist Roberto Dal Negro explained to LifeGate a few months ago. Both the World Health Organisation (WHO) and international scientific literature have been trying to raise awareness for a long time about the plight caused by air pollution, which is tied at least 7 million deaths a year, 500,000 of which in Europe. A global public health issue which is being somewhat sidelined by the novel coronavirus.

air pollution, who, infographic
A WHO infographic about air pollution across the globe

But there are those in the medical and scientific sector who are beginning to link the two factors. Marshall Burke, a scientist and researcher at Stanford University, estimates that two months of lessened pollution “likely has saved the lives of 4,000 kids under five and 73,000 adults over 70 in China”. Therefore, the researcher argues that the decrease in pollutants due to the Covid-19 shutdown in China and in Europe could save more lives than will be lost because of the virus. However, Burke reminds us that his “estimates are a prediction of mortality impacts, not a measurement“. Achieving any kind of certainty about the overall effect will take time. The researcher concludes that “this study isn’t yet possible, as the epidemic is still underway and the comprehensive all-cause mortality data not yet available”.

Walter Ganapini, scientist and honorary member of the EEA‘s scientific committee, recounts that experts have understood the links between pollution from atmospheric particulates and disease incidence for a long time. “Unfortunately, particulates have always been carriers of all kinds of pollutants, from heavy metals to polycyclic aromatic hydrocarbons, from bacteria to viruses. Already in the early 1980s we were studying the phenomenon of carcinogenic aerosols in the Po Valley with the Health & Environment department at ENEA (the Italian National Agency for New Technologies, Energy and Sustainable Economic Development)”.

The correlation between air pollution and spread of the virus

A position paper published recently by the Italian Society of Environmental Medicine (SIMA) urges immediate action on smog. “The analysis seems to suggest a direct relationship between the number of Covid-19 cases and the levels of PM10 pollution across territories”. The study’s authors report that there’s already solid scientific consensus around the link between the incidence of viral infections and concentrations of atmospheric particulates. SIMA’s health experts ask for “restrictive measures to contain pollution” as “the rapid increase of contagion rates that has affected some areas of Northern Italy could be tied to atmospheric particulate pollution acting as a carrier and booster”.

According to scientists at Copernicus, as the coronavirus pandemic is ongoing and different states enact various strategies to address health and environment issues, a new challenge is also emerging: improving future quality of life. This will involve interpreting “the data in a statistically robust way, for instance in order to try to isolate the effects of weather and expected changes in emissions on the one hand and those induced by the measures taken against the spread of Covid-19 on the other”.

Meanwhile, in the midst of the healthcare emergency, some in the scientific sector are proposing a year-long stop-and-go global quarantine in order to invert the contagion curve. Could this be our chance and that of the planet for a breath of fresh air? What is beyond doubt is that while coronavirus comes at a very high price, it offers a unique opportunity to rethink our lifestyles and social models more sustainably.

Translated by

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