Today I needed something that I knew I had, but not needed for at least 15 years, I spent 3 hours looking. They were exactly where I put them, but buried under much other stuff
This is a very specialist type of respirator where the primary protection is from the compressed air supply. The filters are as a back up in the event of air supply failure. Provides an escape option if working in confined spaces etc etc.
An air fed mask doesn’t rely on filters. The air is supplied from the compressor, which needs to be located in a different room from where you are spraying
Perhaps share some details of which mask you have then more info can be provided
Paints containing lead chromates are available but only really used in specialist aviation applications
They are very expensive and highly unlikely to be supplied for automotive use