Pollutants such as sulphur dioxide (SO₂), nitrogen oxide (NO_x) and ammonia (NH₃) can become acidifying components in the atmosphere. These so-called ‘acid rains’ have adverse effects on the climate, air quality, ecosystems, human health and infrastructure.

The sector accounts for 16% of emissions from Belgian manufacturing industry as a whole, and 3% of the total emissions for Belgium (1,5% NOx, 0,8% SOx and 0,7% NH₃). Compared to 2001, the absolute acidifying emissions have more than halved while the production index has more than doubled.

In the chemicals, plastics and life sciences industries, acidifying emissions originate mainly from fossil fuel combustion and the production of sulphuric acid, ammonia and nitric acid (used in producing fertilizers and cleaners and in refrigeration).

By using the best available techniques, the chemical and life sciences industry keeps improving progressively its performance in reducing acidifying emissions. Measures taken to reduce other emissions (such as organic emissions) can make it more difficult to reduce NOx-emissions because they tend to increase when having more post-combustion plants.