On February 24, the Canary Islands were practically isolated from the outside world due to the storm of wind and haze that devastated the archipelago: gusts of 160 km / h and a quantity of suspended dust that made it impossible to see beyond 1 000 meters. Faced with such a panorama, the authorities made an unprecedented decision: to close all Canarian airports. It is one of the most dramatic consequences of living in a world covered in dust.
Much of it comes from as far away as the Gobi desert, the Sahara or the Mojave: between 1 and 3 billion tons of desert rise into the atmosphere each year . But this is not the only source of the dust that we clean in our homes. The oceans provide 3 to 5 billion specks of salt, trees and plants exhale billions of tons of organic compounds, and one third condenses into tiny spheres; plankton, volcanoes and swamps release 20 to 30 million tons of sulfur compounds, and about half are converted into small particles; forest fires release about 6 million tons of soot and the world’s glaciers are slowly grinding down mountains, releasing tiny particles in an amount that no one knows. How much living dust – spores, diatoms, bacteria, viruses, pollen, fibers from decaying leaves, fly eyes and spider legs, scales from butterfly wings, scales from the skin of the billions of animals that inhabit the planet? … reach the atmosphere? And let’s not talk about the several hundred million tons that our civilization releases in the form of nitrogen oxides or sulfur compounds that have an unmistakable tendency to form tiny particles in the sky.
The dust in our houses comes from deserts, oceans, forests, swamps, glaciers …
All this and much more make up the dust that is dispersed throughout the planet in a trip of a few weeks thanks to the incessant breezes that blow at a speed between 8 and 15 kilometers per hour. Most climb to an altitude of 8 to 10 kilometers and will travel perhaps half the globe before falling after several weeks of travel. And it is that at that height there is an intense air current that began to be taken into account when the allied pilots during World War II reported the existence of tailwinds of more than 160 km / h on their flights from the United States to Britain. This “jet stream” is responsible for currently having a difference of half an hour or more between the round trip on intercontinental flights.
But not all the dust we clean from our furniture originates from our planet. About a hundred tons of extraterrestrial dust falls to Earth every day ; they are micrometeorites and cometary particles that do not disintegrate upon entering the atmosphere. The interesting thing is that any of us can collect them: we only have to leave a clean bucket outside on a rainy day. When the sun rises, it is covered with a plastic and the water is allowed to evaporate. In the end, a fine dust will remain at the bottom of the bucket, washed away by the rain. Some of it will be desert sand, but if we bring a magnet close some of those particles will stick to it. A good number of them will be micrometeorites, floating in the air until a drop dragged them to the ground …
