This study established a method for the simultaneous quantitative analysis of 84 odorous compounds by determining proton transfer reaction rate constants, fragmented ion patterns, and product ion yield ratios through experiments on 33 target compounds and by incorporating previously reported data. In this research, a protontransfer- reaction time-of-flight mass spectrometer (PTR-ToF-MS), a real-time analytical instrument, was employed to quantitatively analyze odorants in process streams and final outlet gases from two wastewater consignment treatment facilities (Facility A and Facility B). The expected odor intensity (EOI) estimation method was further applied to identify the primary odor contributors. Among the final outlet gases, the top five odorcausing substances in Facility A were n-pentanal, acetaldehyde, methylmercaptan, n-hexanol, and n-butanal, while the top five odor-causing substances in Facility B were n-decanal, n-nonanal, acetaldehyde, n-butanal, and n-propanol. The cumulative odor contribution rates of these top five odorants were 94.7% and 91.9% for Facilities A and B, respectively. Although PTR-ToF-MS has inherent limitations in distinguishing isomers and isobars, their individual quantification was achieved through complementary identification and separation by TD-GC-MS. This study provides a basis for simplifying quality control in odor analysis compared with conventional trace-level odor testing methods and proposes a more scientific and effective approach for addressing odor problems.

This study analyzed fall accidents involving boatswain’s chairs over the past ten years to investigate their underlying causes and effective preventive measures. The fall accidents in this study were classified according to construction type, work category, and sequence of work. Next, their direct causes were identified by applying the concept of serious injury factor. A focus group interview was conducted with six experts in boatswain’s chair-type scaffolding to derive preventive measures. The results of the investigation indicate that the majority of accidents occurred in maintenance works among construction types, and painting, caulking, and cleaning tasks among work categories. In terms of work sequence, most fall accents occurred while working with descending due to rope defects (loosening, breakage, or insufficient length) and anchorage failures. Based on these findings, two key preventive measures were proposed: (1) installing lifelines as a fail-safe measure to provide safety redundancy, and (2) implementing inherent safety measures to prevent rope defects and failures such as regular inspections, use of high-performance ropes, and ensuring proper anchorage strength. The findings of this study can be utilized in development of effective safety guidelines and policies for boatswain’s chair operations.

Semi-automatic cryogenic-preconcentrator is constructed with time controlling function in preconcentration and desorption stage. GC-FPD and cryogenic-preconcentrator were to analyze gaseous sulfur compounds (hydrogen sulfide, methanethiol, dimethyl sulfide, and dimethyl disulfide) in ppbv level. The objective of this study was to offer reliable methods for sulfur gas analysis in all procedures (keeping, concentration, desorption, and detection). The cryo-concentrator was able to concentrate 4 L gas sample of 40 % relative humidity. The recovery rate of the system was in the range of 92~100 % at 30 seconds of pre-heating time, and method detection limits were shown up 0.16~0.20 ng which is able to quantify 1 ppbv level with 0.5 L gas sample. The storage time of 5 ppbv sample in polyethylene bag led to serious loss (e.g; H₂S: loss of 30% after storage 3 days). It was estimated that the analytical bias was affected more sensitively by storage time after sampling than by cryo-injection procedures in the analysis of hydrogen sulfide and methanethiol.

The volatile odor compounds emitted form a stuffing agent production process were quantified by ATD and GC-MS, and then odor causing compounds were identified by the method of EOI using each TLV. As the results, 72 odor compounds were detected and total concentration was turned up 87.6 ppmv level. In these compounds, aldehyde group is higher 45.49 ppmv than others group, the next is turn up the order of aliphatics, alcohols, esters, ketones. The EOA of aldehyde group show up 101,720 and 97.2%, respectively, the odor causing compounds were identified each of odor 2-Octenal 28.31%, Hexanal 24.06%, Valeraldehyde 16.07%, Butyraldehyde 9.69%, Heptanal 4.97%, Propionaldehyde 4.64%, Acetaldehyde 3.31%. The TLVs of 7 major odor compounds are lower value level of 0.001∼0.0001 ppmv, odor causing even in trace level. We need to be concerned with reduction of aldehyde compounds in the odor problem by a stuffing agent production process or ironing process of the textile containing a stuffing agent.

In this study, GC-MS linked with an automatic thermal desorber was used to quantitatively analyze the odorous and volatile compounds in the gas emitted from a sewage sludge drying facility. In addition, the removal characteristics of these compounds were investigated by using a pilot-scale packed bed wet scrubber. A quantitative analysis for 58 odorous and volatile compounds in the gas was successfully achieved with GC-MS and GC-FPD. The a quantitative analysis revealed the major odorous compounds were hydrogen sulfide and acetaldehyde. In addition, D-type siloxane compounds such as octamethylcyclotetrasiloxane (D4), decamethylcyclopentasiloxane (D5), and dodecamethylcyclohexasiloxane (D6), were quantitatively measured. The concentrations of siloxane compounds measured in the gas were in the range of 4.54- 7.36 ppmv, higher than those in landfill gas. The average removal efficiency of the odorous and volatile compounds in a wet scrubber was 67.37%. D4, D5, and D6, which are hydrophobic compounds, were also removed by as much as 50.68%, 44.56%, and 70.26%, respectively.