To determine the reaction rate coefficient of volatile organic compounds with ozone, the reduction of ozone through a flow-tube reactor was measured by a chemiluminescent detector. The validity of the method was confirmed by examination on isoprene. Consequently, the reaction rate coefficient of 2,5-dimethylfuran, DMF, with ozone was determined as (4.2 +/- 0.9) x 10(-16) cm(3) molecule(-1) s(-1) the first time. It was suggested that ozonolysis can be important for the fate of DMF in the atmosphere.