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Development of Continuous Monitoring Technology for Odorous Compounds in Ambient Air

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The major objective of this project was to develop the sampling and analysis technology of ambient volatile amine pollutants. The development of an auto-sampler for amine pollutants was also an important task. Seven chemicals, including methylamine (MA), ethylamine (EA), dimethylamine (DMA), isopropylamine (IPA), propoylamine (PA), diethylamine (DEA) and trimethylamine (TMA), were selected as the target compounds for testing the analysis method. The amines were collected in deionized water by impinger sampler in field and analyzed by ion chromatography in laboratory. For some of the peak shapes were overlapped in chromatogram for the close retention time, we modified the column operation temperature to change the retention time. As the test result shown, two column operation temperature must be applied to analyze all the 7 target compounds completely. The selected temperatures were 35.0°C and 17.5°C. The calibration curves of amine compounds in ion chromatography with suppressor column were quadratic equations. The coefficient of determination (COD, or R-square, R2) should be higher than 0.99. The R2 values of calibration curves for all the 7 compounds ware higher than 0.997 in our study. Supposing that the air sampling flow was in the rate of 1,000 mL/min and duration was in the time of 30 min, the calculated method detection limit for amines were in the range of 0.1 to 0.5 ppb. The analysis precisions for all the seven compounds were in the range of 0.5 ~ 1.5%. The analysis accuracies of MA, EA, DMA, IPA and PA were in the range of 98~105%, DEA and TMA were in the range of 88 ~ 93%. As for preservation tests, the recoveries of all the seven compounds were better than 92% after storing at 4°C for 14 days. The amine sampling capture efficiencies for DIW in Teflon impinger were 72.7 ~ 101.7%. We had also tested the capture efficiencies of lower concentration air sample, which were in the range of 93.2 ~ 103.4%. An auto-sampler fabricated for ambient amine sampling based on impinger application was achieved and operation parameters were tested. The capture efficiencies for auto-sampler were in the range of 80.9 to 97.2%. Seven field tests of impinger sampling performance were proceeded and four of them had also run the auto-sampler performance testing. Amines were founded in three of the field air ambient. The amines founded in field including MA, EA, DMA, IPA, PA and TMA. The highest concentration of amine pollutants was the TMA in the concentration of 178 ppb. Two technical communication seminar had been taken place on July 2014 and November 2014 individual. The study results were reported in the technical draft for EPA reference.
Keyword
ambient air, amines, odor
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