| 英文摘要 |
The major objective of this project is to compare and develop sampling and analysis technologies of inorganic acids including hydrogen fluoride (HF), hydrogen chloride (HCl), hydrogen bromide (HBr), nitric acid (HNO3), phosphoric acid (H3PO4), sulfuric acid (H2SO4), and formic acid (HCOOH) in ambient air. We have developed a sampling method for the determination of HF and HCOOH in air by serially connecting impinger and personal sampling pump. Ion chromatography using 12 mM KOH as eluent solution was employed for the analysis of fluoride and formate ion absorbed in the deionized water (DIW). The method detection limit (MDL) of HF was 0.07 ppbv in air, and which is much lower than that of the current measurement of HF by using silica gel tube (6.43 ppbv). For HCOOH, the MDL was 0.72 ppbv in air. Besides, the sampling of HCl, HBr, and HNO3 in air were carried out using a double filter combination with a personal sampling pump. After the Na2CO3 treated quartz filter samples were extracted by using a sonication. Ion chromatography using 9 mM Na2CO3 as eluent solution was employed for the analysis of Cl-, Br- and NO3- ions in the extraction samples. The MDL were 2.2 ppbv for HCl, 0.18 ppbv for HBr, and 0.25 ppbv for HNO3 in air, respectively, and which were lower than that of silica gel tubes. Since H3PO4 and H2SO4 exit as liquid aerosol, which were captured by using an un-treated quartz filter with a personal sampling pump. The MDL were 0.35 μg/Nm3 for H3PO4 and 0.30 μg/Nm3 for H2SO4, respectively, which were much lower than that of the current sampling method of silica gel tubes (H3PO4: 27.4 μg/Nm3、H2SO4: 9.7 μg/Nm3).
This project is also to measure the concentrations of these inorganic acids in ambient air near the semiconductor, photoelectronic industry, petrochemical industry, waste incinerator, and glass melting furnace by using the above sampling methods developed. We have carried out 6 sessions of field tests for inorganic acids sampling. HF and HCOOH in ambient air were measured by the impinger method. The concentration of HF was in the range of ND (< 0.07) to 1.8 ppbv and the recovery was 92.7 to 103.7%. The concentrations of HCOOH was ND (< 0.72) to 13.4 ppbv and the recovery was 98.8 to 106.9%. The other inorganic acids (HCl, HBr, HNO3, H3PO4, and H2SO4) were measured by using the filter method. The concentrations of HCl, HBr, HNO3, and H3PO4 were all below the MDL and the recovery were 80.1-92.5%. The concentration of H2SO4 was in the range of ND (< 0.3) to 7.8 g/Nm3 and the recovery was 97.1%. These results indicates that measurement methods of inorganic acids in ambient air developed in this study were feasible. All samples were refrigerated at 4℃ at the lab and need to be analyzed within 14 days of receipt.
Ｗe have written the 5 drafts of the measurement of inorganic acids in ambient air to the reference for EPA. In addition, two sessions of technology demonstration workshop were held in September and October, 2020.
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