The arrival of spring also means dusty city streets, and the main culprit behind this dust is studded tires. In an appearance on ETV's "Terevisioon" on Monday morning, Kristjan Lill, a senior researcher in the Road Engineering and Geodesy Research Group at Tallinn University of Technology (TalTech), noted that issues with this are much more severe in other parts of the world.

"It was determined in one TalTech thesis that about 75 percent of street dust in the air comes from studded tires," he said.

Lill explained that every time a vehicle's wheel turns and a stud on its tire makes contact with the road surface, it scrapes off a minute amount of material from the asphalt.

"A car with studded tires driving one kilometer along city streets wears down about 3 grams of road surface — in other words, a teaspoon of asphalt," he said. "At highway speeds, 100 kilometers per hour (km/h), that amount doubles. Take Tallinn-Tartu Highway, for example: driving 180 kilometers, one car will generate a kilogram of road surface particles, which are thrown into the air and become street dust."

That's why Lill advised drivers to consider whether they really need studded tires.

"If someone drives 1,000 kilometers a year and only around 10 kilometers are on smaller and more slippery roads, is driving the other 990 kilometers on studded tires justified?" he asked. "Maybe they could just drive more carefully on those more slippery stretches."

For those driving in and around Tallinn, studded tires were hardly necessary this winter. Although there has been some freezing rain, which is where studded tires have an advantage over all-season tires, the senior researcher emphasized that the most important thing is for drivers to be aware of what type of tires they have on their vehicle and adjust their driving style according to current road conditions.

"If we have freezing rain one morning, you just need to drive more carefully," he added.

The use of studded tires in Estonia has gone down over time. Recent studies show that around 60 percent of passenger vehicles are equipped with studded tires, compared to 70 percent more than a decade ago.

Weather conditions and road salt also have an impact on the amount of dust generated.

When road surfaces are wet, they wear ten times as much as dry road surfaces. As a result, temperatures close to freezing significantly accelerate the wearing of asphalt. The use of road salt keeps road surfaces wet for longer as well, causing it to wear even faster.

In Estonia, most roads are asphalt, but concrete and gravel roads exist as well. Concrete roads wear more slowly, but they are harder to maintain.

"That's why it has been concluded that when building concrete roads, it's more cost-effective to install an asphalt surface, as this layer is what wears," Lill noted.

The researcher explained that streets are already being designed with traffic load in mind. The higher the traffic frequency, the more durable and wear-resistant stone is used. More wear-resistant materials, however, are also more expensive.

"This brings up the question of whether it is reasonable to use the strongest stone everywhere," Lill acknowledged.

Once street dust has already formed, it can only be alleviated by washing the streets. The first significant rainfalls of the season also help improve things by washing the dust away.

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