And nitrogen dioxide by 60%.
Air quality in China
The second study looked at air quality changes in northern China where the virus was first reported and where lockdowns have been most strict.
Brasseur analyzed levels of nitrogen dioxide and several other types of air pollution measured by 800 ground-level air quality monitoring stations in northern China.
Brasseur and his colleague found particulate matter pollution decreased by an average of 35 percent and nitrogen dioxide decreased by an average of 60 percent after the lockdowns began on January 23.
However, they found the average surface ozone concentration increased by a factor of 1.5-2 over the same time period. At ground level, ozone forms from complex reactions involving nitrogen dioxide and volatile organic compounds (VOCs), gases emitted by a variety of household and industrial products, but ozone levels can also be affected by weather conditions and other factors.
Air quality in China
The second study looked at air quality changes in northern China where the virus was first reported and where lockdowns have been most strict.
Brasseur analyzed levels of nitrogen dioxide and several other types of air pollution measured by 800 ground-level air quality monitoring stations in northern China.
Brasseur and his colleague found particulate matter pollution decreased by an average of 35 percent and nitrogen dioxide decreased by an average of 60 percent after the lockdowns began on January 23.
However, they found the average surface ozone concentration increased by a factor of 1.5-2 over the same time period. At ground level, ozone forms from complex reactions involving nitrogen dioxide and volatile organic compounds (VOCs), gases emitted by a variety of household and industrial products, but ozone levels can also be affected by weather conditions and other factors.
COVID-19 lockdowns significantly impacting global air quality
Levels of two major air pollutants have been drastically reduced since lockdowns began in response to the COVID-19 pandemic, but a secondary pollutant -- ground-level ozone -- has increased in China, according to new research.
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