We've long known both natural and man-made processes produce particulates that can alter atmospheric conditions and, in some cases, be a human health hazard. Now science is giving us some knowledge about how those particulates are formed and react in the air.
A newly published report is based on work done with particulates produced under laboratory conditions. This could mean a great step forward in both pollution and weather control. Said one researcher, "the ratio of oxygen to carbon in a substance affects its ability to absorb water -- and is therefore relevant to the ability of fine particulates to seed clouds."
The research also produced a system for determining where particular particulates originated, from volcanoes to wood smoke to my abrading car tires.