From personal experience, we all know perfectly well: the greatest amount of dust on the roads is usually formed during March-April, while the situation often changes depending on the weather and air flows.
According to the environmental service of the Helsinki region HSY (Finland), the more sun these days and the higher the temperature, the lower the ambient air quality due to the increase in road dust in it. And this, sorry, is harmful: it (dust) can cause symptoms such as a runny nose, cough, itching in the throat and eyes, and even in healthy people.
A study conducted in 2020 by the Finnish Institute of Health and Welfare (THL) showed that the more dust in the air, the more often citizens take sick leave.
The causes of dust on the spring highways "they" and "we" are different. In Europe, for example, it is believed that street dust appears mainly from the impact of studded tires on the asphalt surface. And we would, as they say, have their problems.
According to Anna Klimentova, Chief of Staff of the National Association of Winter Maintenance of Roads, dust storms, as a rule, arise due to the fact that in winter during the period, a sand-salt mixture was used to combat ice.
"We need to understand that in many Russian cities, including St. Petersburg, several tens of thousands of tons of sand mixed with salt are poured onto the roadway and sidewalks every year, and such mixtures do not dissolve," the expert says. "They remain on road surfaces, are crushed under the influence of car wheels and with the arrival of spring they rise into the air. Another thing is also bad in this case: the sand cannot be completely removed, it remains in the pores of the asphalt and pollutes the roadsides."
Can dust provoke an accident
Northwestern State University named after The Mechnikov Ministry of Health of Russia (NWSMU named after Mechnikov) conducted a study at the time and found that the road estimates consist of more than 80% sand. The remaining percentages are erased asphalt and rubber, particles of brake pads, heavy metals from exhaust gases and other waste of the transport complex.
According to research by the Federal Road Institute of RosdorNIA, the remains of a sand-and-salt mixture on asphalt can increase the braking distance of a car, creating on the roadway so the so-called "roller effect". That is, the car cannot slow down due to the fact that it "slides" on the sand. And this, as it is easy to understand, is a direct way to increase the number of road accidents.
It is also bad that sand, according to road specialists, is able to "remove" paint and scratch cars, accelerate the abrasion of surfaces, including rubber and asphalt.
The second class of danger
"The dust mixture can be classified as a hazard class II for humans, since the concentration of heavy metals in its composition is ten times higher than the maximum permissible values," says Anna Klimentova.
"With the arrival of spring, the dust mass rises into the air, enters the lungs of a person and, as has been repeatedly proven by domestic experts and WHO representatives, can reduce immunity and even cause cancer."
Sand negatively affects the environment, in particular, pollutes the soil, therefore
in many countries of the world, programs to reduce air pollution have been in place for more than one year, where a ban on the use of sand in settlements is clearly spelled out.
How much does it cost to clean roads in the spring, and is it possible to somehow reduce costs? According to Anna Klimentova, on average, road cleaning in spring is almost 10 times more expensive than road surface treatment in winter. "Judge for yourself," the expert says, "in March 2019, St. Petersburg spent 760 million rubles on the export of sand, while 76 million rubles were spent on its purchase to combat ice in winter. The first figure is named without taking into account the costs of the city for washing the streets to contain sandstorms."
Of course, in order to save budget money and, most importantly, to preserve people's health, there was an urgent need to use special tools that would reduce the volatility of dust and increase the efficiency of cleaning estimates. These experts usually include dedusters.
Ways to deal with dust on the roads
During a series of tests conducted 3 years ago in Novosibirsk, as well as relying on previously obtained studies with the Moscow Automobile Road Institute (MADI), specialists of the National Association of Winter Road Maintenance were able to select the most optimal compositions dedusters, which are various chloride compounds.
These solutions moisturize road dust and allow you to deal with it more effectively: dust does not rise in clubs, and the roadway and streets can be vacuumed a little earlier than is customary, for example, already at air temperatures from 0 to -10 degrees. "The solution allows you to deal with road estimates in snowless winters and early spring, as well as in summer in case of increased dustiness, allowing you to completely remove up to 95% of the estimates from surfaces without using water," says Anna Klimentova.
The main indicator in the development of dedusters is the coefficient of adhesion to the road, since when it decreases, the probability of an accident increases.
For 1 sq . m of asphalt pavement requires approximately 150 ml of solution. The effect after the dedusting agent persists for 2 weeks, and it also does not require repeated penetration by the machine on the treated surface after the vacuum cleaner. In addition, such solutions have corrosion inhibitors in their composition.
According to the expert, dedusters are also good because they can be used when weather conditions do not allow to clean road surfaces with water and a vacuum cleaner – this greatly reduces the time of exposure to toxic dust on a person and his health.
Roads have started to be washed, general cleaning starts
On March days and in the first days of April, the temperature in our latitudes, as usual, jumps from minus to plus, but on warm, fine days (so that wet cleaning does not provoke the formation of ice), public utilities bring equipment to wash certain sections of city streets with water and shampoo.
In the same St. Petersburg, the first "shower" for roads this season was arranged about two weeks ago. According to the information of the city Improvement Committee, in just one week 11.7 thousand cubic meters of water were spent on washing St. Petersburg roads. At the very least, the dividing strips, the tray area, fences and bus shelters are being cleaned from winter pollution and dust, the number of vacuum sweepers on the streets has noticeably increased, which rid the roads of estimates. Up to 2 thousand tons of estimates and dust are collected every week.
Today, April 1, 2022, general cleaning starts in St. Petersburg. Or, in other words, the spring month for landscaping. Over the next 30 days, district administrations, road and garden enterprises, utilities will have to put in order an area of about 280 million square meters, including, of course, highways.
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