Chinese air pollution slashed by 30% due to coronavirus lockdown

EU satellite image shows 30 PER CENT decrease in air pollution over China as coronavirus outbreak forces factories to close, flights to be grounded and citizens to go into quarantine

  • Copernicus tracked air pollution across most of China in month of February  
  • It compared it to data from the same months from the last four years  
  • Found a decrease in emissions of PM2.5 of between 20 and 30 per cent 
  • Attributed to widespread lockdown following outbreak of the killer coronavirus 

Air pollution in China caused by tiny particles that get in the lungs and cause breathing problems has been slashed dramatically in the wake of coronavirus. 

The country’s government closed down much of its industrial activity and restricted air and car travel to limit the spread of the killer virus. 

Satellite images compared this February’s air quality with the same month from 2017 and 2019. 

It found a decrease in the amount of PM2.5 emissions in China of up to 30 per cent in the same time window that COVID-19 shut down much of the country’s industry. 

PM2.5 are tiny particles about 25 times smaller than the width of a human hair which get inside the body and are linked to respiratory issues.  

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Satellite images compared this February’s air quality with the same month from 2017 and 2019 and found a decrease in the amount of PM2.5 emissions in China of up to 30 per cent (pictured, the percentage difference as shown by the colour bar at the top)

Wuhan, in the Hubei province of China, is known to be where the COVID-19 outbreak currently sweeping the world first started. 

Data from Copernicus, the European Union’s flagship Earth observation arm, tracks atmospheric and climate data related to temperature and pollution on Earth.  

The Copernicus Atmosphere Monitoring Service (CAMS) observed a decrease of fine particulate matter (PM2.5) for February relative to the previous three years of between 20 and 30 per cent, Copernicus said in a statement.

PM2.5 is one of the most important air pollutants regarding health impacts according to the World Health Organization.  

These particles, either solid, gas or liquid in composition, have the potential to trigger or worsen chronic diseases and other respiratory problems. 

Atmospheric readings and computer models were combined to determine changes in PM2.5 levels.  

According to Copernicus, the reduction in PM2.5 can likely be attributed in part to the slow-down in activity due to measures against the COVID-19 spread. 

But the downturn may not be entirely due to the country grinding to a halt, experts believe.

‘Other variables, next to the shutdown, could potentially play a role in the decrease that we have monitored’, explains Vincent-Henri Peuch, Director of CAMS. 

‘China is for instance actively trying to reduce emissions, and meteorological variability between different years must be considered as well. 

‘To subtract these variables out of the equation, we set the duration of three years 2017-2019 to estimate the ‘business as usual’ conditions as a compromise to have a representative estimate of February’s monthly mean, while not considering too long of a period over which emissions vary substantially because of long-term trends.’ 

Medical staff check information as patients infected by the COVID-19 coronavirus are transferred from Wuhan No.3 Hospital to Huoshenshan Hospital in China’s central Hubei province on March 4, 2020

Another major contributor to air pollution is nitrogen dioxide which was recently assessed over China by NASA and the European Space Agency. 

The difference in concentration of nitrogen dioxide is revealed in two maps released by the space agencies. 

The first shows large concentrations of the gas over Beijing and Shanghai in the first three weeks of January before the quarantine was in place. 

A second map in the last three weeks of February reveals a startling difference with almost no nitrogen dioxide visible after China imposed a lockdown in Wuhan and other cities in the Hubei province in a bid to control the spread of the virus.   


Another major contributor to air pollution is nitrogen dioxide which was recently assessed over China by NASA and the European Space Agency. The difference in concentration of nitrogen dioxide is revealed in two maps released by the space agencies taken a month apart

Six additional maps from NASA and ESA focusing on Wuhan reveal the concentration of nitrogen dioxide over three periods including before Lunar New Year, during celebrations and after the festivities in 2019 and 2020

Scientists first noticed the difference around Wuhan, the epicentre of the virus, after Chinese authorities shut down transport in and out of the city as well as shutting down businesses to quarantine the outbreak.  

Nitrogen dioxide is a noxious gas which is released during fuel combustion and emitted by cars, power plants and industrial facilities. 

It forms when fossil fuels such as coal, gas or diesel are burned at high temperatures and can cause a range of harmful effects on the lungs including increased inflammation of the airways and a greater risk of asthma attacks. 

Air quality researcher at NASA’s Goddard Space Flight Center Fei Liu said: ‘This is the first time I have seen such a dramatic drop-off over such a wide area for a specific event.’ 

The drop in nitrogen dioxide also coincided with Lunar New Year celebrations across China where businesses close from the last week of January into early February to celebrate the festival.  

The virus has currently infected more than 93,000 people and killed more than 3,200.   

In the wake of the outbreak, the Chinese government took drastic measures to combat the spread of the microbe to contain its impact.

Companies and factories lay deserted as industry shut down to prevent further spread, a city of 50million people was locked down and temperature checks were mandated. 

China also purpose-built entire hospitals in just over a week to cope with the influx of patients infected with the SARS-CoV-2 and showing symptoms of COVID-19.  

A February report from the World Health Organization and the Chinese government investigated how China responded to the outbreak. 

Numbers of new cases have plummeted in China recently while now around 80 countries have reported cases, including 53 cases in the UK.

The downturn and suppression of COVID-19 was met with scepticism but a team of international researchers found the measures had been effective and the reports were genuine.  

‘China’s bold approach to contain the rapid spread of this new respiratory pathogen has changed the course of a rapidly escalating and deadly epidemic,’ it says. 

‘This decline in COVID-19 cases across China is real.’ 



Carbon dioxide

Carbon dioxide (CO2) is one of the biggest contributors to global warming. After the gas is released into the atmosphere it stays there, making it difficult for heat to escape – and warming up the planet in the process. 

It is primarily released from burning fossil fuels such as coal, oil and gas, as well as cement production. 

The average monthly concentration of CO2 in the Earth’s atmosphere, as of April 2019, is 413 parts per million (ppm). Before the Industrial Revolution, the concentration was just 280 ppm. 

CO2 concentration has fluctuated over the last 800,000 years between 180 to 280ppm, but has been vastly accelerated by pollution caused by humans. 

Nitrogen dioxide 

The gas nitrogen dioxide (NO2) comes from burning fossil fuels, car exhaust emissions and the use of nitrogen-based fertilisers used in agriculture.

Although there is far less NO2 in the atmosphere than CO2, it is between 200 and 300 times more effective at trapping heat.

Sulfur dioxide 

Sulfur dioxide (SO2) also primarily comes from fossil fuel burning, but can also be released from car exhausts.

SO2 can react with water, oxygen and other chemicals in the atmosphere to cause acid rain. 

Carbon monoxide 

Carbon monoxide (CO) is an indirect greenhouse gas as it reacts with hydroxyl radicals, removing them. Hydroxyl radicals reduce the lifetime of carbon dioxide and other greenhouse gases. 


What is particulate matter?

Particulate matter refers to tiny parts of solids or liquid materials in the air. 

Some are visible, such as dust, whereas others cannot be seen by the naked eye. 

Materials such as metals, microplastics, soil and chemicals can be in particulate matter.

Particulate matter (or PM) is described in micrometres. The two main ones mentioned in reports and studies are PM10 (less than 10 micrometres) and PM2.5 (less than 2.5 micrometres).

Air pollution comes from burning fossil fuels, cars, cement making and agriculture 

Scientists measure the rate of particulates in the air by cubic metre.

Particulate matter is sent into the air by a number of processes including burning fossil fuels, driving cars and steel making.

Why are particulates dangerous?

Particulates are dangerous because those less than 10 micrometres in diameter can get deep into your lungs, or even pass into your bloodstream. Particulates are found in higher concentrations in urban areas, particularly along main roads. 

Health impact

What sort of health problems can pollution cause?

According to the World Health Organization, a third of deaths from stroke, lung cancer and heart disease can be linked to air pollution. 

Some of the effects of air pollution on the body are not understood, but pollution may increase inflammation which narrows the arteries leading to heart attacks or strokes. 

As well as this, almost one in 10 lung cancer cases in the UK are caused by air pollution. 

Particulates find their way into the lungs and get lodged there, causing inflammation and damage. As well as this, some chemicals in particulates that make their way into the body can cause cancer. 

Deaths from pollution 

Around seven million people die prematurely because of air pollution every year. Pollution can cause a number of issues including asthma attacks, strokes, various cancers and cardiovascular problems. 


Asthma triggers

Air pollution can cause problems for asthma sufferers for a number of reasons. Pollutants in traffic fumes can irritate the airways, and particulates can get into your lungs and throat and make these areas inflamed. 

Problems in pregnancy 

Women exposed to air pollution before getting pregnant are nearly 20 per cent more likely to have babies with birth defects, research suggested in January 2018.

Living within 3.1 miles (5km) of a highly-polluted area one month before conceiving makes women more likely to give birth to babies with defects such as cleft palates or lips, a study by University of Cincinnati found.

For every 0.01mg/m3 increase in fine air particles, birth defects rise by 19 per cent, the research adds. 

Previous research suggests this causes birth defects as a result of women suffering inflammation and ‘internal stress’. 

What is being done to tackle air pollution? 

Paris agreement on climate change

The Paris Agreement, which was first signed in 2015, is an international agreement to control and limit climate change. 

It hopes to hold the increase in the global average temperature to below 2°C (3.6ºF) ‘and to pursue efforts to limit the temperature increase to 1.5°C (2.7°F)’.

Carbon neutral by 2050 

The UK government has announced plans to make the country carbon neutral by 2050. 

They plan to do this by planting more trees and by installing ‘carbon capture’ technology at the source of the pollution.

Some critics are worried that this first option will be used by the government to export its carbon offsetting to other countries.

International carbon credits let nations continue emitting carbon while paying for trees to be planted elsewhere, balancing out their emissions.

No new petrol or diesel vehicles by 2040

In 2017, the UK government announced the sale of new petrol and diesel cars would be banned by 2040. 

From around 2020, town halls will be allowed to levy extra charges on diesel drivers using the UK’s 81 most polluted routes if air quality fails to improve.

However,  MPs on the climate change committee have urged the government to bring the ban forward to 2030, as by then they will have an equivalent range and price.

The Paris Agreement, which was first signed in 2015, is an international agreement to control and limit climate change. Pictured: air pollution over Paris in 2019.

Norway’s electric car subsidies

The speedy electrification of Norway’s automotive fleet is attributed mainly to generous state subsidies. Electric cars are almost entirely exempt from the heavy taxes imposed on petrol and diesel cars, which makes them competitively priced.

A VW Golf with a standard combustion engine costs nearly 334,000 kroner (34,500 euros, $38,600), while its electric cousin the e-Golf costs 326,000 kroner thanks to a lower tax quotient. 

Criticisms of inaction on climate change

The Committee on Climate Change (CCC) has said there is a ‘shocking’ lack of Government preparation for the risks to the country from climate change. 

The committee assessed 33 areas where the risks of climate change had to be addressed – from flood resilience of properties to impacts on farmland and supply chains – and found no real progress in any of them.

The UK is not prepared for 2°C of warming, the level at which countries have pledged to curb temperature rises, let alone a 4°C rise, which is possible if greenhouse gases are not cut globally, the committee said.

It added that cities need more green spaces to stop the urban ‘heat island’ effect, and to prevent floods by soaking up heavy rainfall. 

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