Volcanic activity affects ozone hole

The mechanism by which volcanic eruption destroys the ozone layer is due to the release of a large amount of ashes (Stenchikov, et al., 2002). After the volcano erupts, ashes will be sent into the stratosphere ( Fig. 1). These ashes contain high concentrations of chlorine and bromine which may stay in the stratosphere for two to five years. During this period, stratospheric ozone is consumed continuously under the influence of solar radiation. It is estimated that volcanic aerosols below 17 km (11.5 mi) above sea level may account for about 18-20% to destroy the ozone layer.

Figure 1. How volcanoes influence ozone layer .

According to the analysis, the formation of the ozone hole over Antarctica in 1992 was caused by the eruption of Pinatubo volcano in the Philippines in 1991 (Fig. 2). Volcanic eruption brought 34-mm-thick plumes into the stratosphere, which had a significant impact on the ozone level. Tabazadeh said: "Both the El Chichon volcano in 1982 and the Pinatubo volcanic eruption in 1991 were sulfur-rich and produced volcanic clouds in the stratosphere for several years." NASA observed that Pinatubo eruptions on the Arctic. The area had widened the ozone layer.

Figure 2. Sulfur Dioxide Cloud over Pinatubo (Source: NASA).

In recent years, many studies show restoration signs of the Antarctic ozone layer. However, in October 2015, the potholes in the ozone layer of the Antarctic were refreshed to the peak of history, triggering doubts about the restoration.Some researchers pointed out that the 2015 figures may result from the Karbubo volcano eruption of Chile in April of that year. Large amounts of volcanic sulfur particles were released into the atmosphere, destroying the ozone layer. Researchers believe that if there is no volcanic eruption, the hole of ozone layer will continue to shrink.

Tabazadeh said: "Volcanic aerosols can cause heavier ozone destruction at warmer temperatures than polar stratospheric clouds do." According to Drdla, volcanic Arctic clouds of 15 to 25 kilometers above sea level (9 to 16 miles)  may increase the spring ozone loss in the Arctic by 70%. Tabazadeh pointed out: "The combination of thicker volcanoes at lower altitudes and natural polar stratospheric clouds at higher elevations could dramatically increase the possibility of Arctic ozone depletion in a cold year.

Climate change combined with large volcanic eruptions will result in ozone loss across the poles, indicating that ozone recovery is more complex than common thought.