Updated: May 23, 2020
In the last month, COVID-19 has become a global pandemic, affecting essentially all parts of the world and almost all aspects of life. The wide-sweeping nature of this virus' impacts means it interacts with other impending crises - including climate change.
The aspect of climate change that has garnered attention in the wake of COVID-19 is air pollution. News articles published in February display satellite images from NASA revealing marked decreases in greenhouse gas, specifically nitrogen dioxide, over the north eastern China. It appears that this decline in greenhouse gas emissions corresponds with the government’s orders to quarantine and halt business/transport in multiple regions of the country (1). The idea behind this association is that during the shutdown, cars, trucks, factories and other manufacturing machinery have stopped functioning, thus expelling fewer greenhouse gases into the environment (2).
NASA officials have noted that steep decreases in pollution levels began near Wuhan, where the virus first appeared. Images of air pollution in Wuhan and China over the course of the COVID-19 shutdowns can be seen below (1).
In previous years, a decrease in greenhouse gas emissions in China around the end of January and early February was not uncommon, due to the celebration of the Lunar New Year. However, the decrease in air pollution that is regularly noted around this time usually returns to normal after the celebration of the holiday. This year, however, the images appear to show that greenhouse gas emissions have not risen again as per usual following the holiday - suggesting that as people continue to stay home, the air pollution is dissipating. Interestingly, Fei Lui, an employee of Nasa’s Goddard Space Flight Center researching air quality, noted that a moderate decline in air pollution was also seen after the 2008 recession (1).
Further, the European Space Agency has released similar images showing declines in greenhouse gas emission from early 2019 to early 2020 in South Korea, Italy, and England (2). Although in South Korea this may be linked to their recent closure of 28 coal power plants (3), they still imply a connection between quarantine measures and air pollution levels.
Although this temporary reduction may not alleviate the effects of climate change (4), it may ease the disease course individuals experience with COVID-19. Specifically, a decline in air pollution may decrease the viruses ability to spread or cause serious infection, as high levels of pollutants like nitrous oxide or particulate matter can increase lung inflammation and lower the body’s ability to fight infection (5).
Despite the clear images obtained by NASA and other space agencies, no peer reviewed papers have reported a downward trend in air pollution as a direct result of quarantine measures. These figures merely suggest that human activity appears to be related to the levels of pollutants in the air. What news articles do highlight is that implementation of low air pollution economies may have the ability to improve air quality and climate change in the future (2). Facing the devastating impacts of this virus, we can at least hope to take a lesson from it - that decreasing industrial activity is that key to a cleaner future. Perhaps we can emerge from this shutdown with a better outlook toward renewable energy sources. Of course, above all, we hope that everyone is staying healthy, safe, and is taking care of themselves during these trying times.
Figure: Decrease in atmospheric nitrous oxide between January and February, 2020 (above); and comparison of atmospheric nitrous oxide between 2019 and 2020 (below). (source: https://www.bbc.com/news/world-asia-51691967?ns_mchannel=social&ns_source=twitter&ocid=socialflow_twitter&ns_campaign=bbcnews)
1. Coronavirus: Nasa images show China pollution clear amid slowdown. British Broadcasting Corporation, 2020. Accessed 4 April 2020, available from https://www.bbc.com/news/world-asia-51691967?ns_mchannel=social&ns_source=twitter&ocid=socialflow_twitter&ns_campaign=bbcnews
2. Watts J & Kommenda M. Coronavirus pandemic leading to huge drop in air pollution. The Guardian, 2020. Accessed 4 April 2020, available from https://www.theguardian.com/environment/2020/mar/23/coronavirus-pandemic-leading-to-huge-drop-in-air-pollution
3. Chung J. South Korea to close up to 28 coal-fired power plants in March. Reuters, 2020. Accessed 4 April 2020, available from https://www.reuters.com/article/us-southkorea-coal-power/south-korea-to-close-up-to-28-coal-fired-power-plants-in-march-idUSKBN20O182
4. Mortillaro N. Global lockdowns might reduce CO2 emissions but won't halt climate crisis, scientists say. CBC News, 2020. Accessed 8 April 2020, available from https://www.cbc.ca/news/technology/covid19-co2-emissions-1.5521271
4. Paton S. When crises collide: The link between air pollution and viral infection. Shake Up The Establishment, 2020. Available from https://www.shakeuptheestab.org/post/air-pollution-and-infection