Cap’n, you’re right – the numbers are screwy.
World gasoline consumption in 1986 was 15.4 million bbl/day (in 2007 it was 21.8 million bbl/day).
http://www.indexmundi.com/energy.aspx?product=gasoline&graph=consumption
Average sulfur content of gasoline in those days was 50 to 300 ppm, say 175 ppm on average
http://www.meca.org/galleries/default-file/sulfur.pdf
Equals 323 metric tons sulfur per day or ~650 mt SO2 per day or 237,000 mt SO2 per year
Mount St. Helens emitted around 500,000 mt SO2 over period 1980-1988 with a maximum annual emission of 222,000 mt in 1980
http://volcanoes.usgs.gov/activity/methods/gas/msh1980-88.php
So the world’s gasoline consumption emitted about as much SO2 as MSH in its maximum year and around four times as much over the 9 years 1980-1988.
The Gipper got it right that there was a whole bunch of SO2 emitted, but his advisors at the time gave him some screwy numbers (today there are a helluva lot more of them and they call them “czars”, but isn’t that what they do these days, as well?)
Max