I love this idea. I would wager that calcium carbonate dust has a higher ballistic coefficient than SOx (ratio of mass to cross section, a measure of ability to

I love this idea. I would wager that calcium carbonate dust has a higher ballistic coefficient than SOx (ratio of mass to cross section, a measure of ability to stay aloft), meaning if we overdo it (unlikely but the most common concern), the decay rate would be faster. Plus would also mitigate acid rain somewhat, and isn't noxious the way SOx is.