Since it only was a semi-serious question I'll assume you knew this, but I still think the balance is a good argument to have when you run into deniers.
This is a good intro to the broad issue of volcanoes and climate: http://www.cotf.edu/ete/modules/volcanoes/vclimate.html
A more in-depth treatment of sulfur aerosols in the upper atmosphere: https://en.m.wikipedia.org/wiki/Stratospheric_sulfur_aerosol...
Here’s a breakdown of all the gasses typically releases during eruptions and their various effects: http://volcanology.geol.ucsb.edu/gas.htm
If there’s anything else I can do, please don’t hesitate to ask.
https://scied.ucar.edu/ozone-layer
Here’s one with more technical analysis along with the exact chemistry:
http://www.theozonehole.com/ozonedestruction.htm
Here’s a broad overview with historical perspectives from the American Chemical Society: https://www.acs.org/content/acs/en/education/whatischemistry...
I hope this helps.