E: ·When a volcano erupts, large volumes of carbon dioxide, sulfur dioxide, water vapor, dust and ash are released into the atmosphere.
·Sulfur dioxide reacts with the water in the air to form sulfur based chemicals.
·Together with the dust and ash, these particles reflect the sun's ray, resulting in the decrease of global temperature.
E': E.G., In 1991, Mount Pinatubo in the Philippines erupted and released 17 million tonnes of sulfur dioxide. The sulfur-based particles lowered the temperature in the northern hemisphere by 6℃.
For example, the eruption of Mount Tambora in 1875 caused the mean global temprature to drop by 1.7℃.