Although welding fume from normal steel is not one of the most dangerous types, it is far from good for your health. Among other things, it contains particles of iron oxide, which can cause siderosis. (chronic inflammation of the lungs).
When welding with MIG/MAG and MMA, there are heavy fume emissions, meaning that both a respirator and good ventilation in the workplace are necessary. When welding ordinary steel, the RSG T-Air Powered Respirator with particle filter is recommended.