Objective To analyze the noise spectral characteristics and compliance with occupational exposure limit (OEL) in the workplaces of the printing industry in Shenzhen and to provide a basis for the prevention and control of noise hazards in the printing industry.

Methods By a purposive sampling method, 153 printing companies were studied, the noise levels at work sites were measured, and noise spectral characteristics analysis was done if the level was higher than OEL. The classification of similar noise spectrum-related groups was conducted using inter-group connection cluster analysis.

Results A total of 566 noise-exposure work sites in these companies were surveyed. Among these sites, the noise level at 76 sites was higher than OEL, with a non-compliance rate of 13.43%. The effectiveness rate of noise protection facilities was 55.19%, and the effectiveness rate of ear muffs or earplugs was 61.07%. The 76 test points of noise exceeding the OEL were distributed in 13 workplaces, including Mounting Paper, Die Cutting Machine, Perforation, Sheet Separation, Film Lamination, Varnishing, Die Cutting, Spray Gun, Die Cutting Machine, Printing, Adhesive Binding/Gluing, Folding, and Binding. Through cluster analysis, 13 workplaces were divided into 4 categories: Film Lamination, Binding, Adhesive Binding/Gluing, Folding, Sheet Separation, and Die Cutting Machine for one category, where the noise had a gradual rise in low frequency and a peak appearing at 500 Hz to 2 000 Hz, followed by a gradual decline; the Spray Gun was classified as one category, where the noise had a stable rise in low frequency and a peak appearing at 4 000 Hz, followed by a decline; the Varnishing, Die Cutting, Perforation, Printing, and Die Cutting Machine were classified as one category, where noise with a peak appeared at 125 Hz to 500 Hz. The noise at the Perforation, Printing, and Die Cutting Machine showed a single peak pattern and gradually declined after the peak, while the noise at the Varnishing and Die Cutting showed a slight rise at 8 000 Hz after the peak and gradually declined. The Mounting Paper was classified as one category, where noise with a peak appeared at 31.5 Hz, followed by a gradual and stable decline.

Conclusions The compliance of noise with OEL in the workplaces of Shenzhen's printing industry was not optimistic and should be given high attention, and effective engineering control measures should be taken based on noise spectral characteristics.