A system and a method for reduction or elimination of environmentally harmful or “greenhouse” gases in situations in which gaseous hydrocarbons are flared or vented from an oil and gas well are disclosed. The system configures to inject a chemically reactive, or dispersive, or reactive and dispersive atomized mist into a gas flow line leading to a flare stack. The mist reacts with the gas in the flow line to convert methane to hydrogen and carbon monoxide and to reduce other harmful gases, facilitating a clean-burning, compact flare of blue color due to the presence of primarily hydrogen, some carbon monoxide, and a small amount of residual methane. The hydrogen and carbon monoxide may be captured and stored before reaching the ignition point at the top of the flare stack.