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FMI: Covid restrictions impact traffic volumes, improve air quality

Studies show there are fewer toxic exhaust fumes in the air than in previous years.

Pölyä Helsingin keskustassa.
Air pollution drops due to Covid restrictions. Image: Silja Viitala / Yle

Between street dust and pollen, springtime in Finland can often mean a rapid deterioration in air quality.

The country is at the height of the spread of seasonal street dust, but current coronavirus restrictions may be providing some relief from this annual predicament, according to Pia Anttila, a researcher at the Finnish Meteorological Institute (FMI).

"Our experience, after one year of the pandemic, is that as traffic volumes have decreased, so have emissions, and air quality has improved. If the Covid-19 situation takes a turn for the worse, an improvement in air quality can be expected again," Anttila says.

Air pollution dropped dramatically in spring 2020

Traffic has a significant impact on urban air quality. Cars spread street dust from the surface of the road as well as release nitrogen dioxide into the air. A year ago, the coronavirus pandemic gave rise to urgent restrictions and many people started working from home in an effort to reduce social contacts.

This swift change in behavioural patterns was seen in pollution statistics, with car-related nitrogen dioxide emissions dropping drastically.

The amount of nitrogen dioxide in the air is indicative of how much people drive. Therefore, emissions can also be considered an indication of the efficacy of restrictions. Authorities recently used nitrogen dioxide values as a measure of human mobility, the same way mobile phone location data has been used previously.

The biggest change in pollution, in relation to last year, was in the Helsinki metropolitan area where the Uusimaa border closure cordoned off the area from the rest of the country for three weeks. Air pollution could decrease again this spring if new coronavirus measures restrict movement after the Easter holidays.

According to Anttila, the levels of nitric oxide started to increase again in the summer but have now stabilised at about 20 percent lower than normal.

Long-term environmental benefits?

Could the pandemic have long-term benefits for air quality? Possibly, if working from home becomes the new normal, Anttila says. The nitric oxide levels will however return to normal as soon as we resume regular traffic patterns.

In China, air pollution rose above pre-coronavirus levels in the summer as industry revved back up. Researchers estimate that the same can happen in Europe.

In Finland, the amount of nitrogen dioxide in urban air has been declining for years, in part because of more fuel-efficient cars.

At the same time, awareness of the health effects of air pollution has increased.

Will face masks remain a staple after the pandemic?

The widespread use of masks, such as the FFP2 mask, which protects against particles like street dust, could also bring relief to those suffering from pollen allergies, Anttila adds.

During the pandemic, the use of masks has become more widespread, and they may continue to be beneficial for high-risk groups by bringing much-needed relief during the street dust season.

Anttila says that although air quality routinely deteriorates in spring, Finland still remains a top contender for the cleanest air in Europe.

The FMI monitors air pollution in real time on its website, in order to inform citizens about air pollution exceeding threshold values.

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