为了研究自制的纳米TiO₂对环境空气中有机污染物的光催化降解能力，文中通过自制光催化反应系统，研究了纳米TiO₂光催化降解甲醛的过程，考察了环境相对湿度、光照强度、气体流量、甲醛初始质量浓度等因素对甲醛的气相光催化降解反应的影响．结果表明：纳米TiO₂光催化降解甲醛的最佳相对湿度为50％，适宜气体流量为1．20L／min；光降解率并不会随光照强度的增加无限制地增大，甲醛初始质量浓度的增加将降低光催化氧化降解速率．

In order to evaluate the photocatalytic degradation capacity of self-prepared nano-sized TiO₂ for the organic pollutants in the air, a self-developed photocatalytic degradation reaction system was adopted to analyze the photocatalytic degradation process of formaldehyde and to investigate the factors influencing the degradation, such as the relative humidity, the illumination intensity, the gas flowrate and the initial mass concentration of formaldehyde. The results indicate that the photocatalytic degradation performs best at a relative humidity of 50% and a gas flowrate of 1.20 L/min; and that the photocatalytie degradation rate does not increase unlimitedly with the increase in illumination intensity, but it decreases with the increase in the initial mass concentration of formaldehyde.