Moscow was covered by radiation fog: what is it and how is it dangerous

Thick fogs and accumulation of harmful impurities in the air are forecast in the Moscow region by the end of the week. The reason for this was the persistent anticyclonal weather. What is radiation fog, whether it is related to radiation and what danger it carries — in the Izvestia material.

What happened

Radiation fog and accumulation of harmful aerosols in the air are predicted in the Moscow region by the end of the week, said Roman Vilfand, scientific director of the Hydrometeorological Center of Russia. According to him, the reason for this is the establishment of anticyclonic weather.

"The anticyclonal circulation that controls the weather in Moscow will contribute to the accumulation of harmful impurities in the surface air layer. They will not dissipate," the expert said.

The thick fog will remain until the beginning of next week. It is especially noticeable at night and in the morning.

"This is the so-called radiation fog, and by the end of the week, with a stationary anticyclone, condensation of water vapor and fog conditions will be present. The fog will be noticeable," Vilfand said.

What is radiation fog?

Radiation fog is an atmospheric phenomenon that occurs due to the radiation cooling of the earth's surface. The term is related to the heat transfer process, not to the effect of radioactive radiation. At night, the earth loses heat rapidly through long-wavelength radiation. Because of this, the adjacent moist air cools down to the dew point and fog forms.

"There were clouds, so there was humid air under them. The clouds were blown away, but the air remained. And when the earth cools down, the temperature goes to the dew point. That is, droplets condense from the air. It's a fog. First of all, the part of the air that is adjacent to the cold ground cools down. Fog forms near the ground," Igor Shkradyuk, coordinator of the industrial greening program at the Wildlife Conservation Center, told Izvestia.

The phenomenon is most often observed in conditions of an anticyclone, clear weather and weak wind.

What is the danger of radiation fog?

Despite the frightening name, radiation fog does not pose a direct threat to health. However, it is potentially dangerous for city residents and drivers for a number of reasons.

• A sharp decrease in visibility, which increases the risk of accidents on the roads.

• Fog traps harmful aerosols and impurities near the earth's surface, which can worsen the environmental situation in a megalopolis.

• Increased air saturation with polluting particles can become a problem for people with respiratory diseases.

Thus, in conditions of radiation fog, residents are advised to exercise caution on the roads and limit their outdoor activities if possible.

All important news is on the Izvestia channel in the MAX messenger.