In the first subject of this dissertation, various materials powder such as TeO2, TiC, and AlF3 was directly synthesized by employing microwave plasma at atmospheric pressure. Also, we investigate characteristics of as-synthesized TeO2, TiC, and AlF3 nanopowders, respectively. The second subject addresses the pulsed microwave plasma torch treatment of aluminum surface (Al). The surface treatment of Al sheets using atmospheric pressure pulsed-microwave plasma is investigated in terms of gas mixtures. The total surface free energy of the Al sheets before and after the Ar/H2 plasma treatment, estimated from the Owens-Wendt equation, increased from 19.38 to 82.40 mN/m, showing, a significant improvement in hydrophilicity. The elimination of chemical and biological warfare agents as a stimulant was placed on the third subject of this dissertation. The burner flames were sustained by injecting hydrocarbon-fuels into the microwave plasma torch in air discharge. The FTIR and GC spectra indicated near perfect elimination of DMMP in the microwave plasma burner, respectively. As the final subject of this dissertation, Properties of microwave plasma torch operating at a low pressure was presented. The plasma profile at a low pressure is shown to be asymmetric with higher density on the incoming side of the microwaves. Gas temperature and electron density of the torch plasma measured by making use of OES from hydroxide radicals and electron density from hydrogen Balmer beta line is shown to increase drastically at high pressure operation, as the microwave power increases, respectively. Disintegration of nitrogen fluoride (NF3) indicates that a microwave plasma torch operating at a low pressure can efficiently generate an abundant amount of chemical radicals.