Purification and Remediation of Ambient Air by Photocatalysis

Abstract

Air purification/remediation technologies for removing hazardous pollutants emitted in the atmosphere are keenly sought in order to improve the air quality in large cities, although it is difficult to efficiently capture such pollutants that are transported and diffuse rapidly. Recently, a passive method based on photocatalysis is proposed for energy-and labor-saving air purifjication by removing low-level nitrogen oxides under the sunlight. In this review, air purification methods utilizing plants (trees), soil, adsorbents, and flue gas deNO_x methods are surveyed and the requirements for practical purification systems are discussed together with the principle of the photocatalytic method, fabrication and characterization of prototype air purifying materials, performance at polluted roadside, and future prospects.