The use of printing inks containing organic solvents by the master, offset and screen printing process implies the release of volatile organic compounds (VOCs) to the work environment. In this study, the volatile content of inks was evaluated by using a thermogravimetric analyzer (TGA), in which the solvent is evaporated. And, to identify the the characterization of VOCs emissions from printing inks, air samples were collected in a thermal extractor (TE) and analyzed by thermal desorption-gas chromatography/mass spectrometry (TD-GC/MS). Weight loss curves suggest that there are two main stages, such as dry fastening and chemical curing. As the result, the first stage of mass loss (below 100oC) was due to VOC evaporation. At this stage, master and offset inks are slightly stable thermally up to 100oC, but screen inks weight loss increases distinctly beyond 25oC. The volatile content is higher in screen inks than in the master and offset inks. The results of the mass-specific TVOC emission rate of the master, offset, and screen inks were 6.3 μg/(g·h), 8.4 μg/(g·h), and 212.2 μg/(g·h), respectively. Then the TVOC emission rate of the screen inks was 25~33 times higher than that of the master and offset inks. The main species were 1-Ethyl-2-pyrrolidinone, 1,2,4-Trimethylbenzene, 1,2,3-Trimethylbenzene, 1,2,4,5-Tetramethylbenzene, 1-Methoxy-2- propanol, Decane, Undecane, and Nonane.

The effects of essential oils on pH, pathogens, and volatile fatty acids (VFA) in two poultry litters were investigated through a lab study. Essential oil-added poultry litters were randomly divided to two groups: control (200 g poultry litter) and Treatment (50 g thymol/Briefly, 200 g broiler litter was treated with or without 50 g thymol (Control and T1, respectively; 1 groups) and 200 g duck litter was treated with or without 50 g carvacrol (Control and T2, respectively; 2 group). Adding thymol to broiler litter increased the pH, reduced pathogens, and did not affect VFA. Interestingly, adding carvacrol slightly reduced the pH of duck litter, but had no significant effect on reducing pathogens and VFA. This difference is probably because the essential oil used and the properties of the two litters are different. In addition, pH was thought to control the odor generated from the litter, but this has not been proven. Further field studies should focus on clarifying this point.