Solvent base color uses more solvent ( most solvent base colors use a 1:1 mixture ) ,therefore putting out more VOC's then the 2k primers , sealers , and clears to apply , and some of those primer , sealer & Clear products only require catalyst to apply , or use a small amount in the reduction ratio for spraying , so the VOC content is less .

And some Companies waterborne systems are not truly waterborne , as they require a type solvent for reduction , not deionized water like some .

But there is a company here in Kansas that is developing a true Waterborne Clear . Dont know how well it works or lasts .