At the end of the last century, acid rain was a major environmental problem in many developed countries. Although the air in Europe has become much cleaner in the meantime, industry and traffic cause the emission of the environmentally harmful gases carbon monoxide and nitrogen dioxide — and even particulate matter — mainly through the combustion of fossil raw materials such as coal and crude oil. 

Since 2020, the European directive has tightened national emission limits for air pollutants, forcing European countries to adopt stricter regulations with lower limits. In case of SO₂ H₂O₂ can be used to comply with the reduced limits. 

There are basically two technologies for SO₂ exhaust gas purification: Caustic gas scrubbers, which produce a waste effluent stream, and oxidative scrubbers using H₂O₂, which produce sulphuric acid that can be concentrated and reused.

Removal of mercaptans, hydrogen sulfide (H₂S), and sulfur dioxide (SO₂) from wastewater or exhaust gases is achieved by using a wet scrubber with hydrogen peroxide. It is also used to reduce toxicity and odors in paper mills, rendering plants, and metal smelting, and in pharmaceutical, pesticide, chemical, or petrochemical plants.

Hydrogen peroxide is used in various technological processes to reduce environmental pollution caused by exhaust gases. For example, nitrogen dioxide and nitrous oxide emissions can be greatly reduced in steel industry production processes that use nitric acid in a pickling process. Nitrogen dioxide is also produced to a lesser extent in the paper industry.