Energy is used in virtually every industrial process and is produced by the combustion of fossil fuels. This process results in the release of by-products such as carbon dioxide (CO2), sulphur dioxide (SO2), nitrogen oxides (NOx) and particles.

Along with NOx, SO2 emissions are responsible for acidification. Both of these compounds may be carried long distances by winds. In the atmosphere, they are transformed into sulphur and nitrogen acids that are washed down by rain where they reach soil and surface waters and interfere with the development of certain organisms. Acid rain also causes damage to plants, to buildings and equipment, and causes corrosion of metals. It can and does directly affect the raw material of the paper industry - the forests. Reduction of these effluents is, therefore, a matter of high priority for the industry.

Since 1990 the paper industry has massively reduced its SO2 emissions (by 80%) using a variety of means: switching from heavy fuel oil to sulphur-free and low-sulphur fuels; replacing fuel oil by natural gas; implementing precise process control techniques.

Emissions of NOx are much more difficult to control than sulphur emissions. Even so, they too have been reduced by 40%. This is of vital importance because, under the influence of solar radiation and in the presence of NOx, volatile hydrocarbons are transformed into ozone and other substances causing, for example, respiratory problems. Ozone also has a negative influence on plant growth.

The challenge for the future is to develop and implement new technology that will further reduce the industry's NOx emissions. The increased use of biofuels will help in this since they emit less NOx than fuel oil to produce the same amount of energy.