When you feel that rain is muddy and it leaves cars and windows dirty, it is rain dust falling from the sky.
Rain dust is also known are muddy rain, and is the name given to different forms of precipitation that contain enough dust to be visible to the naked eye.
This type of rain is pretty common around the coasts of the Mediterranean Sea, where the air is full of dust from the African deserts that is transported north by atmospheric depressions.
— The Life Pile (@thelifepile) April 25, 2018
Although the phenomenon is generally frequent, it has been increasing in frequency since the early 1990s.
Muddy rain is usually very alkaline, and includes a mixture of chemicals such as sulfate and sea salt. Depending on where the dust is coming from, it could also be carrying fertilizer particles.
Of course, rain dust has both positive and negative effects on the environment and humans. When it comes in spring or early summer, it can hurt vegetation and damage flowers that had just blossomed. It also turns the world dirty and muddy.
— The Life Pile (@thelifepile) April 18, 2018
However, when it occurs during fall and winter, it can help combat erosion and help forming long-term soil by providing it with essential minerals and compounds.
And since the some of the muddy rain around the world is high in pH, it counteracts the effects of acid rain by neutralizing its pH value.
But in some cases dust rain can be very dangerous.
In 200, Greece was attacked by radioactive muddy rain that had traveled from the Chernobyl disaster site in Ukraine.