Open AccessOccupational Exposure to Volatile Organic Compounds and Mitigation by Push‐Pull Local Exhaust Ventilation in Printing Plants
Author(s) -
Leung Michael K.H.,
Liu ChunHo,
Chan Alan H.S.
Publication year - 2005
Publication title -
journal of occupational health
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.664
H-Index - 59
ISSN - 1348-9585
DOI - 10.1539/joh.47.540
Subject(s) - indoor air quality , environmental science , ventilation (architecture) , volatile organic compound , occupational exposure , offset printing , waste management , environmental engineering , environmental chemistry , environmental health , medicine , chemistry , materials science , engineering , mechanical engineering , organic chemistry , inkwell , composite material
Occupational Exposure to Volatile Organic Compounds and Mitigation by Local Exhaust Ventilation in Printing Plants: Michael K.H. Leung et al. The University of Hong Kong, Hong Kong —The extensive use of multiple organic solvents in offset lithographic printing causing high emissions of volatile organic compounds (VOCs) indeed poses a serious risk to printing workers’ health. In this study, indoor air quality (IAQ) assessments were carried out in seven printing plants and the main objectives were to understand the effect of VOC emissions on IAQ and develop effective mitigation measures to protect workers. The thorough gas chromatography/mass spectrometry (GC/MS) measurements showed that although a variety of VOCs were presented in the indoor air, none of them was found close to individual 8‐h time‐weighted average (TWA) of the occupational exposure limit (OEL). The additive effect was also found below the critical value of unity. However, short‐term personal exposure to total volatile organic compounds (TVOCs) was exceedingly high when a print worker carried out blanket and ink roller cleaning procedures. Therefore, the occupational health risk was mainly due to repeated short‐term exposures during intermittent VOC‐emitting procedures rather than long‐term exposure to background VOCs. Push‐pull local exhaust ventilation (LEV) was identified as an effective mitigation measure. Computational fluid dynamics (CFD) analysis was conducted to study the push‐pull LEV operation. It was found that there existed a threshold LEV air flow rate for an abrupt reduction in the worker's exposure to VOCs. The reduction was less sensitive when the LEV airflow was further increased beyond the threshold. These phenomena, consistent with experimental results reported by other investigators, were explained by detailed CFD analysis showing the competition between the general ventilation and the push‐pull LEV to become the dominating driving force for the resultant local flow pattern.