How does conservation reduce air pollution

Well, burning coal, fuel, gas or even garbage; creates gaseous effluents, usually subject to certain regulations that establish the limits of each pollutant. 
Solar, wind power and other technologies of energy generation, do not generate gaseous effluents. 

Conserving coal, fuel, gas and garbage(that's why we need to also recycle), conserving these certain things, will help reduce air pollution by a LONG run. 

Also, changing to solar, wind power, and using other technologies will help also help reduce air pollution.

Hope I helped :)