Alcohols-aldehydes-NO(x)-air system smog chamber experiments were undertaken and the reaction model was developed based on the experimental results. Ozone formation behaviors of alcohols and aldehydes were investigated with the computer simulation by changing the ratio of reactants. The effect of alcohol fuel on O3 formation was estimated. Aldehydes have high reactivity in the atmospheric photochemical reaction. Alcohols can promote O3 formation substantially under reactive conditions. The efficient control of aldehydes emissions is especially important.