Emissions of sulphur dioxides and nitrogen oxides cause acidification of the environment. Because this is a cross-border problem, international agreements have been made.
The National Emission Ceilings Directive is a European directive that obliges each member state to reduce the emissions of sulphur dioxides and nitrogen oxides (but also of volatile organic compounds and ammonia) to a fixed value.
In Belgium, the necessary efforts are divided among different sectors, including the steel industry. Steel production causes significant NOx and SO2 emissions. NOx emissions are formed by thermal processes at high temperatures, by combustion processes and by fuel-related facilities such as furnaces. SO2 emissions are intrinsic to the sulphur content of raw materials and coal used in the combustion and production processes.
Technologies to reduce those emissions and that can be applied in the steel industry are unfortunately not readily available. Still, ArcelorMittal Gent has already put in a great effort over the years.