Also, the cooling effect sulphate aerosols can cause only really happens at high altitudes. At low altitudes the reflected light is less likely to escape to space, and the aerosols fall out of the air faster.

Even if they reached high altitudes, one of the effects of being in the atmosphere is moving with the wind, across entire hemispheres. And at tropospheric heights, sulphates, their products, and other byproducts of combustion may destroy ozone at significant levels.

There may come a day where aerosol-based geo-engineering becomes a part of climate management, but it's definitely not with bunker fumes.