Current levels of the chemicals bromine and chlorine in the stratosphere -- where ozone protects life on Earth from harmful ultraviolet radiation -- could double or even triple with an eruption, German researchers said.
They based that on the levels of the chemicals released from 14 volcanoes in Nicaragua during the past 70,000 years, LiveScience.com reported Tuesday.
Bromine and chlorine "love to react -- especially with ozone," researcher Kirstin Kruger, a meteorologist in Kiel, Germany, said in a statement.
"If they reach the upper levels of the atmosphere, they have a high potential of depleting the ozone layer," Kruger said.
By studying chemicals in rock layers deposited before and after historic eruptions, the researchers determined the average eruption released two to three times the quantity of human-produced bromine and chlorine currently in the stratosphere.
In large, explosive eruptions that can send clouds of ash miles high, as much as 25 percent of the ejected gases can reach the stratosphere, they said.
The researchers presented their work at a scientific conference in Iceland.