|dc.description.abstract||This study is to develop a monitoring method involving the use of proton-transfer reaction mass spectrometry (PTR-MS) to investigate chemical pollutants released from industrial parks. Taking the advantages of the PTR-MS’s ultra-low detection limits and high temporal resolution, the trigger-sampling technique was coupled with PTR-QMS to capture plume events from the industrial parks. The triggered samples were then analyzed with in-laboratory GC/MS/FID (gas chromatography/mass spectrometry/flame ionization detector) for 108 volatile organic compounds (VOCs) to characterize the chemical compositions of the plume events. In this study, two types of mass spectrometry were involved: quadruple (called PTR-QMS) and time of flight (called PTR-ToF/MS).
This study demonstrated a 10-day field observation in Pingjhen Industrial Park for characteristic pollutants. By targeting selected VOCs characteristic of the Pingjhen Industrial Park, flask samples were collected in sequence when the PTR-QMS detected concentrations surpassing the pre-set trigger levels. Eighteen event samples were triggered as a result, and were analyzed by in-lab GC/MS/FID to reveal the composition of 108 VOCs. It was found that majority of the constituents was oxygenated VOCs (OVOCs), including acetone, butanone, methyl isobutyl ketone (MIBK), methyl butyl ketone (MBK), ethyl acetate, vinyl acetate, isopropanol and methyl tert-butyl ether (MTBE), accounting for 15% - 75% of the total 108 VOCs for the event samples. When including the compounds that were measured by PTR-MS but cannot be analyzed by GC/MS/FID (e.g., ethanol, acetaldehyde and acetic acid), the percentages of OVOCs increased to 55% - 82%.
Compared with our previous trigger-sampling studies, OVOCs accounted for 15% - 60% of the total 108 VOCs in Hsinchu, 32% - 84% in Chungli, but only 8% - 10% in the Taipei metropolitan area. Such large fractions of OVOCs in the vicinity of industrial park could explain the frequent odor complaints by the local residents.
Moreover, contrasting to the urban environment such as Taipei, where methyl tert-butyl ether (MTBE) was the major component of OVOCs, organic compounds commonly used in industry, such as ethyl acetate, acetone, butanone, isopropanol, etc., were the primary contributors to OVOCs from these industrial parks (e.g., Pingjhen, Hsinchu and Chungli). By summarizing the monitoring results of the three industrial parks, a list of top ten pollutants was established for each industrial park, on which aldehydes, acids and amides were the common ones worth noticing and more related to foul smells. Usually these polar compounds are not suitable to be sampled by flasks, and their recoveries from GC/MS analysis are poor. They are also difficult to be detected by other methods (e.g., FT-IR) due to their low ambient levels. This study has proven that PTR-MS could the most sensitive, efficient and rapid method to detect ambient OVOCs.||en_US|