Why do metal smelting plants produce so much pollution

Metal smelting plants are made to release and remove impurities from metal. The ore is removed through several different processes and in doing so releases the energy from such work and dust and minerals that are removed from the ore itself. Refer below \/ for the needed energy in these processes

carbon in the coal or charcoal used releases vast amounts of CO2 into the atmosphere which is causes a buildup in the ozone and sunlight when reflected off the earth and back into the carbon saturated ozone layer causes what we call the greenhouse effect. Carbon Dioxide is therefore referred to as a greenhouse gas

Wow that a lot of text for my tiny so i no wanna answer