The restrictions on public life in the wake of the Corona pandemic not only reduce the Covid 19 case numbers – they also promote health. During this time, fewer people have died from the effects of air pollution than usual, according to a study. The number of asthma diseases in children has also decreased due to the clean air.
To reduce the contagion, many countries severely restricted public life several weeks ago, closed schools, sent workers to their home office and imposed exit restrictions. As a result, traffic decreased drastically, especially in the metropolitan areas, industry and power plants reduced their production and thus their emissions. A few weeks ago, first satellite images by NASA and the European space agency ESA showed that the extensive corona lockdown, for example, significantly reduced nitrogen oxide levels over Wuhan, but also in many metropolitan areas in Europe compared to the previous year.
20 percent less air pollutants
Zander Venter from the Norwegian Institute for Natural Research in Solo and his colleagues have now examined in more detail how much air pollution has decreased and what health effects this could have. For their study, the researchers evaluated measurement data on nitrogen dioxide, ozone and particulate matter (PM2.5) for the first two weeks of the corona lockdown in 27 countries. They compared these values from satellites and around 10,000 measuring stations – adjusted for meteorological effects – with the pollution levels that prevailed at the same time in 2019. The scientists then used epidemiological methods to calculate how many deaths and asthma diseases in children have been avoided due to the reduced pollution caused by the previous lockdown. They also identified the health effects of reducing air pollution by the end of 2020.
The result: According to the data, air pollution decreased by around 20 percent overall in the first two weeks of the lockdowns. The nitrogen oxide load decreased on average by 29 percent, the ground-level ozone by around eleven percent, as the researchers report. For particulate matter, the changes fluctuated between an increase of ten percent and a decrease of 28 percent depending on the country and region. Because air currents and weather conditions had considerable disruptive effects, a slight decrease in particulate matter by nine percent was observed on average, but it did not result in a uniformly significant trend.
7400 fewer deaths
Nevertheless, Venter and his colleagues were able to determine that this decrease in air pollution must already have had positive health effects. “We estimate that around 7400 premature deaths and 6600 cases of asthma in children were avoided in the first two weeks of the lockdowns worldwide,” says senior author Jos Lelieveld from the Max Planck Institute for Chemistry. The majority of these cases are due to the at least regionally significantly reduced particulate matter pollution. In China and India alone, the researchers avoided 1,400 and 5,300 premature deaths.
“We do not want to say that the current restrictions are desirable or sustainable for the economy,” emphasizes Venter. “But the current situation shows the importance of the often overlooked global air pollution crisis.” The results are a clear indication of the potential health benefits that result from cleaner air. If the reduced pollutant emissions would continue until the end of 2020, even more people could benefit from it: “The cumulative effect of the reduction of nitrogen dioxide, ozone and particulate matter for the rest of the year could avoid 780,000 premature deaths worldwide and 1.6 million asthma cases in children”, the scientists report.
“In order to reduce air pollution in the long term even after the corona crisis, we should aim to phase out the burning of fossil fuels,” says Lelieveld. “This would not only improve the health of people worldwide, but also protect the climate in the medium term.”
Source: Max Planck Institute for Chemistry; Technical article: Preprint medRxiv, doi: 10.1101 / 2020.04.10.20060673 (PDF)