Copper smelting is a process that generates significant pollutants. The high temperatures involved in smelting can lead to the release of sulphur dioxide, a major contributor to acid rain. Furthermore, copper smelting slag, a byproduct, contains various heavy metals that can leach into the soil and water, posing risks to ecosystems and human health. While carbon monoxide can be a pollutant, its release in lethal quantities specifically from copper smelting is not the primary concern compared to SO2 and heavy metal leaching.