The invention is related to an apparatus made of microwave plasma burner for a large-volume elimination of toxic airborne chemical and biological warfare agents. The apparatus can purify the interior air of large volume in an isolated space such as buildings, public transportation systems, and military vehicles contaminated with chemical and biological warfare agents. The apparatus consists of a microwave plasma torch connected in series to a fuel injector and a reaction chamber for elimination and burnout of toxic airborne warfare agents in large quantities. Hydrocarbon fuel in gaseous or liquid state injected into the microwave plasma torch evaporates instantaneously, generating a large volume of plasma flame in the reaction chamber where the oxidation mechanism eliminates the chemical and biological warfare agents that pass through the reaction chamber. The apparatus can also purify air contaminated with volatile organic compounds and eliminate soot from diesel engines.