PRESS TRUST OF INDIA
London, Jan 14: The first Covid-19 lockdowns led to significant changes in urban air pollution lev-els in global cities such as Delhi and London, but the changes were smaller than expected, a new UK study claimed Thursday.
After developing new correc-tions for the impact of weather and seasonal trends, such as re-duced NO2 emissions from win-ter to summer, researchers led by the University of Birmingham ex-perts evaluated changes in ambi-entNO2, 03andfineparticle (PMI’S) concentrations arising from lock-down emission changes innglobal cities. These cities include Beijing Wuhan, Milan, Rome, Madrid,
ondon, Paris, Berlin, New York, Los Angeles and Delhi. The team of international sci-entists discovered that the beneficial reductions in NO2 due to the lock-downs were smaller than expected, after removing the effects of weather In parallel, the lockdowns caused
(weather-corrected) concentrations of ozone in cities to increace.
“Rapid, unprecedented reduc-tion in the economic activity pro-vided a unique opportunity to study the impact of interventions on air quality. Emission changes associ-ated with the early lockdown re-strictions led to abrupt changes in air pollutantlevels but their impacts on air quality were more complex than we thought and smaller than we expected,”
said Lead-author Zongbo Shi, Professor of Atmospheric Biogeochemistry at the University of Birmingham. “Weather changes can mask changes in emissions on air qual-ity. Importantly, our study has pro-vided a new framework for as-sessing air pollution interventions, by separating the effects of weather and season room the effects of emis-sion changes,” he said. NO2 is a key air pollutant from traffic emissions, associated with respiratory problems, while ozone is also harmful to health, and dam-ages crops.