Is 2011 going to be the beginning of a mini ice-age nuclear winter?

Remember last year's dramatic outburst of volcanic material into the upper atmosphere from northern Europe and this year's ongoing, ever growing, catastrophic radioactive nuclear upheaval from multiple plants run by General Electric (GE) in Japan... Are all those airborne particulates capable of staying suspended long enough to block rays from the sun enough to lower our planet's temperature significantly? Or could all the floating matter I'm bringing up in topic here be beneficial in stabilizing global temperature fluctuations for some reason? If so why would that be?