Air pollution in China back to pre-Covid levels
and Europe may follow
Cleaner skies were a silver lining of pandemic but
data indicates air quality receding as lockdowns eased
Damian
Carrington and Niko Kommenda
Wed 3 Jun
2020 09.18 BSTLast modified on Wed 3 Jun 2020 16.50 BST
Air
pollution in China has climbed back to pre-pandemic levels, and scientists say
Europe may follow suit.
Air
pollution causes at least 8m early deaths a year, and cleaner skies were seen
as one of the few silver linings of Covid-19. Experts have called for action to
help retain the air quality benefits of lockdowns, and measures taken to date
have included expanding cycle lanes and space for walking in cities.
Data from
the Centre for Research on Energy and Clean Air (Crea) shows concentrations of
fine particles (PM2.5) and nitrogen dioxide (NO2) across China are now at the
same levels as one year earlier. At the height of the country’s coronavirus
response in early March, NO2 levels were down by 38% from 2019 and levels of
PM2.5 were down by 34%.
“The rapid
rebound in air pollution and coal consumption levels across China is an early
warning of what a smokestack industry-led rebound could look like,” said Crea’s
lead analyst, Lauri Myllyvirta. “Highly polluting industries have been faster
to recover from the crisis than the rest of the economy. It is essential for
policymakers to prioritise clean energy.”
The energy
consultancy group Wood Mackenzie predicts China’s oil demand will recover to
near normal levels in the second quarter of 2020.
In Wuhan,
the city at the centre of the epidemic, NO2 levels are now just 14% lower than
last year, having briefly dropped by almost half. In Shanghai, the latest
levels are 9% higher than last year.
European
cities have also seen a big dip in air pollution during the virus outbreak.
Data from the Copernicus Atmosphere Monitoring Service (Cams), which tracks
pollution in 50 European cities, shows that 42 of them recorded below-average
levels of NO2 in March. London and Paris had 30% reductions in NO2, a pollutant
that is mostly produced by diesel vehicles.
“We do
expect pollution to rebound, but we have not been able yet to show that,” said
Vincent-Henri Peuch, the director of Cams. He noted that the Cams data showed
average air pollution levels across cities. “Next to a busy road, the effect of
traffic reduction will be higher – up to 70% or 80% [reduced pollution] in
places,” he said.
Distinguishing
the pollution changes caused by the lockdowns and their subsequent relaxations
from other factors, such as weather and chemical interaction of pollutants, is
complex. Spring is the most polluted season in western Europe in normal years,
owing to the start of the agriculture cycle which causes ammonia emissions that
go on to form particles over cities.
The Cams
team is now working with the Barcelona Supercomputing Centre to untangle these
factors and produce robust estimates of the coronavirus effect.
Peuch said
what happens next to air quality in European cities remained to be seen. “We do
not know how people’s behaviour will change, for example avoiding public
transport and therefore relying more on their own cars, or continuing to work
from home.”
Gary
Fuller, an air pollution expert at Kings College London, said: “Rather than let
this time be forgotten, the United Nations and environmental campaigners are
urging governments to ‘build back better, to invest in the future not the
past’, to ensure that our global recovery has sustainable legacy.”
Air
pollution has been linked to heart and lung damage and many other conditions
including diabetes and damaged intelligence. It is likely to affect virtually
every organ in the body.
There is
growing evidence linking exposure to dirty air to increased risk of death from
Covid-19, prompting calls to keep air pollution low to help avoid the dangers
of a second wave of infection.
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