We have experienced a significant decline in air pollution level in the past few weeks across major global cities. The change in air quality has a direct link with the decrease in traffic flow and economic activity.

To curb the spread of COVID-19 (novel coronavirus), many governments have implemented different measures to limit public gatherings such as encouraging remote work, suspensions on manufacturing and travel restriction.

Video Source: European Space Agency


Reduced NO2 in China

  • The Guardian revealed the sharp reduction in nitrogen dioxide (NO2) levels over China during the first outbreak across the country between January and February.
  • By comparing the images from Nasa and the European Space Agency (ESA) pollution monitoring satellites, the Nasa scientists noticed the levels of NO2 in eastern and central China were 10-30% lower than what is normally observed for the same period.

Video Source: The Wall Street Journal


Changes in worldwide Air Pollution

  • We see the same drop in air pollution in Korea, Europe and America with the coronavirus quarantine from late February onwards.
  • The Guardian has compared the NO2 readings from ESA’s Sentinel-5P satellite between the year 2019 and 2020.
  • One of the obvious examples would be Milan and northern Italy as the NO2 levels of the area has fallen by about 40%.


Compare the pollution level of several countries on the Guardian website:


  • The dramatic improvement in air quality is more obvious in India. The Himalayan mountain range is now visible from more than 100 miles away.
  • This is the very first time in almost 30 years, people in the northern Indian state of Punjab can see the mountain tops clearly due to the improvement in air quality after industries shut down and travel ban.


Temporary improvements in Air Quality 

Some experts regard the worldwide lockdown as the “largest-scale experiment ever” to illustrate the effectiveness of reducing vehicle and industrial emission to curb air pollution, as well as to fight the climate crisis.

But the recent decline in global air pollution is temporary and everyone is expecting a strong bounce back in the economy after the pandemic comes to an end. The recovery would boost a quick return of air pollution level and some cases may come back with a vengeance.


Breathing dirty air as usual or Make a difference now?

NO2 is one of the major pollutants produced during fossil fuels combustion for power generation and vehicle transportation. Long-term exposure to NO2 may decrease lung function and increase the risk of respiratory symptoms. NO2 is also a precursor to the formation of acid rain. A study has also revealed the dirty air could be one of the important factors increasing the death rate of COVID-19.

For years, scientists have emphasized the environmental and health impacts of air pollution. The global pandemic could be a great chance for us to think about environmental hazards on people’s health and our policies on emissions and industry.

If we do not have a safe and sustainable living environment to support the growth of healthy population, the economy would be at risk again.


Photo/ Tom Siu

Story posted on
25th Apr, 2020


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