Mount Etna Erupts
Mount Etna, on the Italian island of Sicily, is Europe’s most active volcano, having erupted half a dozen times in the past decade alone. During an eruption, a volcano spews gases that had been dissolved in molten rock. One of those gases is sulfur dioxide, which turns into sulfuric acid in the atmosphere and then condenses into sulfate aerosols. Those aerosols can linger for months in the upper atmosphere, where they block sunlight and destroy atomospheric ozone.