One of the things associated with volcanos erupting other than lava and rocks is pollution. Volcanic pollution is generaly in three forms, gases, ashes, and cinders.
Volcanic gases are emitted during erutions and periods of inactivity. In an eruption the gas relesed is mostly(80%) water vapor(H20), with smaller amounts of sulfur dioxide(S02) and carbon dioxide(C02). These gases rise and can harm or depleate the ozone layer.
Volcanic ashes are composed of pulverized rocks and accompanied by a number of gases with are then coverted into droplets of sulphuric acid and hydrochloric acid wich can be dangerous to the atmosphere and also aircraft. Some particles are smaller than dust so they can take a long time to settle and that is another thing that can make it dangerous because it can travel a long way.
Cinders are small pieces of hot, burning particles of rock. Cinders can be launched a long way and they can cause damage to the surronding enviroment. Smoke is also created by cinders and the create a small amount of pollution is caused.
Ash clouds cause damage to aircraft because they can get into the engines and melt the parts and cause malfunctions. There have been many cases of damage caused by volcanic ash, there have even been a few plane accidents and wreaks. There are places around the world called Volcanic Ash Advisory Centers(VAACs) that warn people about possible ash dangers in their areas.
In the long past of eruptions and produced pollutions from volcanos they have caused alot of other damage besides just lava and rock , but gases and ashes that damage the atmosphere and can damage envirments of people and animals. Eventually these gases cause global damage and can cause depleation of the ozone layer and can cause global warming, but compared to all the damage we ourselves cause the second hand damage of volcanos does not compare to the rest of pollution.