In order to reduce gaseous pollution emissions and achieve the goal of cleaner production in paper industry, in this study, (I) First, the concentrations of four potential compositions of gaseous pollutants, TVOC, HCHO, H2S and CxHy, in the ambient air on 30 sampling sites in 5 pulp and paper mills were analysed. The analysed results were discussed in the following aspects: (a) the levels of four gaseous pollutants on all the sampling sites in five mills; (b) gaseous pollution differences due to different production processes; (c) gaseous pollution comparisons on the common sites. (II) Secondly, the compositions of VOCs in a secondary fiber paper mill were determined with GC-MS method. The main identified substances in the four sites were as follows: (a) waste paper sorting room: alkanes, phenols and esters; (b) paper machine hall: benzene homologues, alkanes, ethers and phenols; (c) vacuum pulp outlet: benzene homologues and phenols; (d) office area: benzene homologues and phenols. (III) Third and last, aiming a the detected formaldehyde and benzene pollutants, a photo-catalytic reactor was developed and its performance with respect to degradation was studied. The performance tests of reactor showed that both formaldehyde and benzene could be completely degraded, but the degradation time for benzene was much longer than that for formaldehyde.