Plummeting pollution exposes transport’s role in air quality crisis

Evidence is emerging that air quality is improving as a result of the coronavirus restrictions. A study in Spain reported a fall of 55% in air pollution in the second half of March, and a series of satellite maps shows air pollution ‘falling dramatically’ across Europe. The figures have prompted new calls for stricter measures to control road traffic when the virus has cleared

Despite the EU passing its Air Quality Framework Directive in 1997, breaches of air pollution limits have been a regular feature of the past 20 years. Indeed the European Commission has begun legal proceedings against 15 member states in which cities systematically exceed permitted levels of pollutants or lack adequate strategies to monitor and reduce air pollution. The move towards banning high-emitting cars from city centres has been part of the solution, with more than 250 European cities introducing Low-Emission Zones. But the drastic reduction in traffic caused by ‘lockdown’ restrictions introduced to fight Covid-19 is providing a demonstration of what happens when road traffic is heavily reduced.

Now the first evidence of improved air quality is appearing.

In Spain, T&E member Ecologistas en Acción has published a report on air monitoring between 14 March – the day Spain’s government declared a state of emergency – and the end of the month. It shows that pollution levels caused by nitrogen dioxide (NO2) in the most important Spanish cities had decreased by 55% compared with what is normal for this time of year. The analysis is based on official NO2 data collected from 125 measuring stations in 24 cities as measured over the last decade.

The report shows the biggest reductions came from readings on the Mediterranean coast, where measurements resembled those normally found only in very rural areas. By contrast, Spain’s northern coast reported less pollution decline, which Ecologistas says may be due to unidentified meteorological factors. The fact that Spain had high levels of atmospheric instability in March could have exaggerated the reduction in air pollution, as instability keeps air circulation high.

At the same time, the European Public Health Alliance (EPHA) published a series of maps based on satellite data provided by the European Space Agency which it says reveal how air pollution ‘has fallen dramatically in cities across the world due to Covid-19 lockdown measures’. The maps show Madrid, Paris, Milan, Frankfurt, Brussels and other cities enjoying a reduction in average NO2 levels in the period 5-25 March compared with the same period last year.

EPHA officials warned that air pollution over recent years has already damaged the respiratory systems of those currently suffering from coronavirus symptoms. It says that, despite the fall in air pollution levels in Milan, northern Italy is a pollution hotspot and is also the centre of Europe’s coronavirus outbreak.

This is supported by a new study from America, which claims to offer the first clear link between long-term exposure to air pollution and Covid-19 death rates. The study, done at Harvard University and based on an analysis of 3,080 counties across the US, reveals a ‘large overlap’ between Covid-19 deaths and diseases associated with long-term exposure to fine particulate matter, and specifically finds that areas with high PM2.5 levels are associated with higher death rates from the virus.

T&E’s air quality manager, Jens Müller, said: ‘The findings show unequivocally that in most cities, air pollution is caused largely by polluting vehicles, so it should come as no surprise that a reduction in road traffic improves the air. But this is nothing to rejoice about. 

‘The current drop in air pollution results from a health tragedy, and a lockdown is not a solution for clean air. However, what the findings do stress is the absolute need to avoid going back to levels of polluting mobility once the corona crisis is over. That means a clear roadmap towards the EU’s new zero pollution target must be written into the legislation governing the European Green Deal.’

Similar falls are expected to be recorded for CO2 emissions and other greenhouse gases. The head of the Global Carbon Project, Professor Rob Jackson of California’s Stanford University, has been quoted as saying he would ‘not be shocked to see a 5% or more drop in carbon dioxide emissions this year, something not seen since the end of World War II.’