I always go back to what 'THEY' said when mt. St. Helens went off up in here...
'THEY'... The official scientific ex-spurts... said that volcano let off more pollutants than the entire history of man.
If that is true (which, who the hell knows if it is), then the obvious thing to do is stop all these volcanoes from going off all the time - There's one going off somewhere almost always... Do that and things would clean up considerably, without anything men can do.
So make volcanoes illegal.