The Element
Summer 2022
How iodine in desert dust destroys ozone
(World AtlasThe Four Spheres Of The Earth WorldAtlas)
The iodine cycle is a biogeochemical cycle (a flow of chemical elements between living organisms and the environment) that primarily consists of natural and biological processes that exchange iodine through the lithosphere, hydrosphere, and atmosphere, in both oceanic and terrestrial transport processes . It can be found naturally in air, water and soil. The most important sources of natural iodine are the oceans. Iodine can also be found in the human body, and is mostly concentrated in the thyroid gland (a gland in the neck that produces hormones).
Ozone is a gas composed of three atoms of oxygen. It occurs both in the Earth's upper atmosphere and at ground level. Ozone can be good or bad, depending on where it is found. At ground level, ozone is a harmful air pollutant because of its effects on people and the environment, and it is the main component in “smog”. In the atmosphere, ozone is very beneficial as it absorbs a lot of harmful UV radiation. Atmospheric researchers have been interested in the idea that dusty layers of air have very little ozone. Speculations surrounded that some kind of dust-surface chemistry was eating up ozone, but no one had been able to show that happening in laboratory experiments. Recent studies, led by the University of Colorado, in Boulder, shows that iodine in desert dust can decrease ozone air pollution but can prolong the lifetimes of greenhouse gas. The team made precise atmospheric measurements from aircraft of iodine monoxide ions inside dust layers from the Atacama and Sechura deserts in Chile and Peru, and were 22
