New Analysis of Ozone Layer Hole Chemistry Available

Following the Montreal Protocol, which entered into force on January 1, 1989, the production and release of dangerous chemicals known as chlorofluorocarbons (CFC) in the planet's atmosphere has been banned. These organic chemical compounds, made primarily out of carbon, chlorine and fluorine, proved to be extremely harmful for the ozone layer, causing a large hole in this protective cloak right above Antarctica. Now, the ozone layer is beginning to heal, but NASA experts continue to keep an eye on the interactions between what remained of CFC.

As part of the most recent such study, a team of investigators led by expert Michelle Santee, based at the NASA Jet Propulsion Laboratory (JPL) in Pasadena, California, looked at how human-produced chlorine chemicals derived from CFC interact with one another. Some of the aspects the team was most interested in was determining how night-day temperature variations influence the concentrations of chlorine monoxide, one of the most hazardous chemicals for the ozone layer. The study had a practical component, which used datasets collected from Earth-watching satellites, as well as a theoretical one, in which an advanced chemical model was used to model the region.

“Our comprehensive study uses multiple years of Arctic and Antarctic satellite observations to quantify the nighttime balance of ozone-destroying chlorine chemical compounds. By gaining a better knowledge of this balance, scientists will be able to make more accurate predictions of polar ozone loss, especially in twilight and in the Arctic, where conditions are often only marginally favorable for ozone destruction,” explains Santee. She is also the author of a new paper detailing the findings, which appears in this month's issue of the esteemed journal Proceedings of the National Academy of Sciences.

According to readings collected by the Microwave Limb Sounder (MLS) instrument on the NASA Aura satellite, chlorine monoxide tends to form chlorine peroxide in the chilly temperatures that the Antarctic experiences during the night. The team therefore concluded that the delicate balance between these two dangerous chemicals is dependent on temperatures to a great degree. During the six years it has been in orbit, the MLS collected tens of thousands of measurements of nighttime chlorine monoxide levels, which JPL researchers used as a reference point for the new study.