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[AAS07-P13] Development of a sampling method for the simultaneous collection of NO and NO2 in the air for isotopic analysis of emitted NOx
Keywords:NOx, Isotopes, Nitrogen
Nitric oxide (NO) and nitrogen dioxide (NO2) are collectively referred to as nitrogen oxide (NOx). NOx is a primary pollutant of the atmosphere and is involved in urban environmental issues such as photochemical smog, acid rain, the production of tropospheric ozone, and human health. To understand the mechanisms of these issues, it is important to elucidate the sources of NOx. Nitrogen isotopic composition of NOx is a useful tool to estimate the sources and sinks. Although there are various methods for measuring the nitrogen isotopic composition of NOx, the NOx collection efficiency of each method has not been fully validated. Therefore, a simple and well-verified method for NOx collection efficiency is required.
Several methods have been reported to collect atmospheric NOx. In this study, we adopted the wet method reported by Fibiger et al. (2016). Atmospheric NOx can be efficiently collected at high flow rates using their method. On the other hand, there is the disadvantage of the large blank of nitrite/nitrate ions in the solution. We improved the method and developed a simpler, more efficient method with less NOx blanks. By using the developed method, the nitrogen isotopic composition of NOx can be measured with a precision within ±1‰, and the blank of nitrite/nitrate ions in the solution can be reduced to 1/10 compared to the original method. We present the details of the developed method and the nitrogen isotopic composition of NOx collected in Tsukuba and Shibuya.
Reference
Fibiger, D. L., Hastings, M. G., Lew, A. F., and Peltier, R. E. Collection of NO and NO2 for Isotopic Analysis of NOx Emissions, Anal. Chem. 2014, 86, 24, 12115–12121.
Several methods have been reported to collect atmospheric NOx. In this study, we adopted the wet method reported by Fibiger et al. (2016). Atmospheric NOx can be efficiently collected at high flow rates using their method. On the other hand, there is the disadvantage of the large blank of nitrite/nitrate ions in the solution. We improved the method and developed a simpler, more efficient method with less NOx blanks. By using the developed method, the nitrogen isotopic composition of NOx can be measured with a precision within ±1‰, and the blank of nitrite/nitrate ions in the solution can be reduced to 1/10 compared to the original method. We present the details of the developed method and the nitrogen isotopic composition of NOx collected in Tsukuba and Shibuya.
Reference
Fibiger, D. L., Hastings, M. G., Lew, A. F., and Peltier, R. E. Collection of NO and NO2 for Isotopic Analysis of NOx Emissions, Anal. Chem. 2014, 86, 24, 12115–12121.