LONDON, May 6 (Xinhua) -- The COVID-19 pandemic has seen traffic pollution for most parts of Britain falling, but more dangerous urban ozone -- a dangerous air pollutant which can cause airway inflammation in humans -- is probably being generated, experts from the University of Manchester said Wednesday in a new study.
According to the Manchester research, levels of nitrogen oxide have shown reduction in most locations in Britain during mid-March and April when lockdown has been in full force, with the level of decline ranging from 20 to 80 percent. Manchester's downtown area has seen a 70 percent reduction in nitrogen oxide (NO2).
The drop can be attributed to the decline of traffic on the nation's roads, either private cars or public transport, amid nationwide lockdown, said the report.
"Observations in cities across the UK show marked decreases in nitrogen oxides but with corresponding increases in ozone during lockdown," said Hugh Coe, professor of Atmospheric Composition and a leading member of the research team.
The Manchester team speculated that photochemical production of ozone may become more important in urban areas during summertime in these low NOx conditions. NOx is a generic term that includes nitric oxide (NO) and nitrogen dioxide (NO2) .
"This is an important finding because while ozone is extremely important for screening harmful solar ultraviolet radiation when present higher up in the atmosphere it can be a dangerous air pollutant at the Earth's surface. Increasing surface ozone above natural levels is harmful to humans, plants, and other living systems because ozone reacts strongly to destroy or alter many biological molecules," said the report.
Unlike NO2, there was no evidence of a decrease in PM 2.5, the tiny particulates that can make the air appear hazy, the study added.
"While these particles are produced by vehicles, they are also known to originate from domestic wood burning and chemical reactions involving emissions from industry and agriculture, so there has been no significant improvement in air quality in that regard," said professor Coe. Enditem
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