Oxidizing agent

Similar term(s): oxidizing properties, oxidant.

Any substance, such as oxygen (O₂) or chlorine (Cl₂), that will readily add (take on) electrons. The opposite is a reducing agent.

Source: US EPA Drinking Water Glossary  

Oxidizing agents are substances with a high capacity to react with specific chemicals thus building up new compounds with different properties (sometimes more hazardous, sometimes less).

Boron

DBP

DINP-DIDP

Air quality in Europe

Chlorine Sodium Hypochlorite