Empty roads amid the COVID-19 lockdowns may have prevented 32,000 air pollution-related deaths worldwide, scientists predict
- Massachussets Institute of Technology experts analysed global pollution levels
- Data come from satellite and ground-based measurements across 36 nations
- The team found that lockdowns significantly lowered NO₂ levels across the globe
- However, levels of secondary pollutants were found to vary region-by-region
Some 32,000 premature deaths from air pollution were prevented as a result of COVID-19 lockdowns that kept many cars off of the road, a study has concluded.
The pandemic substantially reduced atmospheric concentrations of nitrogen dioxide around the world, Massachussets Institute of Technology experts found.
Despite this shift, similar global reductions were not recorded for both ozone and fine air particle pollutant levels (PM2.5), the researchers noted.
These pollutants are formed by so-called secondary reactions — and therefore their accumulation is dependant on the background state of the local atmosphere.
The findings, the team said, demonstrate the ned to tailor air quality policies to specific regions in order to better reduce global levels of secondary pollutants.
Some 32,000 premature deaths from air pollution (pictured) were prevented as a result of COVID-19 lockdowns that kept many cars off of the road, a study has concluded
The pandemic substantially reduced atmospheric concentrations of nitrogen dioxide around the world, Massachussets Institute of Technology experts found. Pictured: shifts in atmospheric nitrogen dioxide levels across the study regions, shown in shades of blue
‘Responses to the COVID-19 outbreak resulted in one of the largest short-term decreases in anthropogenic emissions in modern history,’ wrote the team, who were led by engineer Guillaume Chossière.
‘Using global satellite observations and ground measurements from 36 countries in Europe, North America, and East Asia, we find that lockdowns led to reductions in NO₂ concentrations globally.’
This, they added, resulted ‘in around 32,000 avoided premature mortalities, including around 21,000 in China.’
In their study, the team explored whether local stay-at-home orders correlated with regional changes by using a time-series model to estimate what air pollution levels would have looked like had lockdowns not been in effect.
The team found that the relationship between PM2.5 levels and changes in nitrogen dioxide varied widely across 38 of the study regions.
At the same time, 88 regions were seen to undergo decreases in atmospheric nitrogen dioxide level, but corresponding increases in ozone.
‘Using global satellite observations and ground measurements from 36 countries in Europe, North America, and East Asia, we find that lockdowns led to reductions in NO2 concentrations globally, resulting in around 32,000 avoided premature mortalities, including around 21,000 in China.’ Pictured: COVID-19 mortalities (grey) vs averted deaths from air pollution (blue)
‘The disconnect between NO₂ and ozone changes stems from local chemical regimes,’ the researchers wrote.
‘The COVID-related lockdowns demonstrate the need for targeted air quality policies to reduce the global burden of air pollution, especially related to secondary pollutants,’ they concluded.
The full findings of the study were published in the journal Science Advances.
Revealed: MailOnline dissects the impact greenhouse gases have on the planet – and what is being done to stop air pollution
Emissions
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.
Particulates
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.
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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