UN: Lockdowns caused brief air quality gains

GENEVA — The U.N. weather agency says the world — and especially urban areas — experienced a brief, sharp drop in emissions of air pollutants last year amid lockdown measures and related travel restrictions put in place over the coronavirus pandemic.

The World Meteorological Organization, releasing its first ever Air Quality and Climate Bulletin last week, cautioned that the reductions in pollution were patchy — and many parts of the world showed levels that outpaced air quality guidelines. Some types of pollutants continued to emerge at regular or even higher levels.

“COVID-19 proved to be an unplanned air-quality experiment, and it did lead to temporary localized improvements,” said Petteri Taalas, the WMO secretary-general. “But a pandemic is not a substitute for sustained and systematic action to tackle major drivers of both population and climate change and so safeguard the health of both people and planet.”

The WMO study analyzed changes in air quality around the main pollutants, including sulfur dioxide, nitrogen oxides, carbon monoxide and ozone.

The Geneva-based agency noted an “unprecedented decrease” in pollutant emissions as many governments restricted gatherings, closed schools and imposed lockdowns.

Oksana Tarasova, head of WMO’s atmospheric environment research division, said the impact of such measures on major pollutants was short-lived.

When measures to reduce mobility mean “there are no cars on the street, you see the improvement in air quality immediately. And of course, as soon as the cars go back on the street, you get the worsening back.”

That compared to “long-lead greenhouse gases” behind global warming like carbon dioxide, whose atmospheric levels can take many years to change.

WMO cited declines of up to nearly 70% in average levels of nitrogen oxides, which are largely emitted through transportation and burning of fossil fuels.