What is 'black rain' seen in Moscow after drone strike?
What's the story
Residents of Moscow have reported seeing dark, oily drizzles after a Ukrainian drone strike on the Kapotnya oil refinery. They also reported black stains on cars, roads, and clothing. The incident has sparked concerns over a phenomenon known as "black rain," which is contaminated precipitation mixed with soot and smoke. The Kapotnya refinery, one of Moscow's most important fuel facilities, was hit in what Russian officials described as the largest drone attack on the city since the war began.
Environmental impact
How does black rain form?
Black rain is caused when smoke, soot, and other pollutants mix with moisture in the atmosphere. This results in precipitation that contains tiny carbon particles and unburnt hydrocarbons, giving it a dark appearance. The phenomenon is usually linked to industrial fires, volcanic eruptions, or wildfires. A famous example of this was after the atomic bombing of Hiroshima in 1945, when radioactive soot mixed with rain clouds.
Fuel disruption
How did Kapotnya refinery fire lead to black rain?
The smoke from the burning petroleum products at the Kapotnya refinery likely caused the black rain. Oil and diesel tanks release soot, carbon particles, and oily aerosols into the air when they burn. If these particles come into contact with humid conditions or light rainfall, they can be scavenged from the atmosphere and deposited back onto surfaces. The Kapotnya refinery supplies around 40% of Moscow's petrol and half its diesel fuel.
Health advisory
Health risks from exposure to contaminated particles
Exposure to these contaminated particles can irritate the eyes, skin, and respiratory system. This is especially concerning for children, older adults, and people with asthma or other lung conditions. Although Moscow authorities have denied reports of "oil rain," they have advised residents near the affected area to keep windows closed. Vulnerable groups are also advised to temporarily leave the district due to possible health risks from suspended smoke particles and pollutants in the air.