Identify the typical pollutant released by metallurgical smelters, thermal power stations, and cement manufacturing facilities.

Explanation

Among the listed pollutants, sulfur dioxide (SO2) is the primary emission from metallurgical smelters, thermal power plants, and cement production units. While nitrogen oxides (NOx), mercury (Hg), and fluorine (F) may also be emitted in smaller quantities, SO2 remains the most common pollutant associated with these industries.