@article{oai:nagoya.repo.nii.ac.jp:02001906, author = {Xu, Hao and Tsunogai, Urumu and Nakagawa, Fumiko and Li, Yijun and Ito, Masanori and Sato, Keiichi and Tanimoto, Hiroshi}, issue = {15}, journal = {Rapid Communications in Mass Spectrometry}, month = {Aug}, note = {Rationale: The triple oxygen isotopic composition (Δ^17O) of tropospheric ozone (O3) is a useful tracer for identifying the source and is essential for clarifying the atmospheric chemistry of oxidants. However, the single nitrite-coated filter method is inaccurate owing to the nitrate blank produced through the reaction of nitrite and oxygen compounds other than O3. Methods: A multistep nitrite-coated filter-pack system is newly adopted to transfer the O-atoms in terminal positions of O3 to nitrite on each filter to determine the Δ^17O of O3 in terminal positions (denoted as Δ17O(O3)term). The NO3^− produced by this reaction is chemically converted into N2O, and continuous-flow isotope ratio mass spectrometry (CF-IRMS) is used to determine the oxygen isotopic compositions. Results: The reciprocal of the NO3^− quantities on the nitrite-coated filters in each sample showed a strong linear relationship with Δ^17O of NO3^−. Using the linear relation, we corrected the changes in Δ^17O of NO3^− on the filters. We verified the accuracy of the new method through the measurement of artificial O3 with known Δ^17O(O3)term value that had been determined from the changes in Δ^17O of O2. The Δ^17O(O3)term of tropospheric O3 was in agreement with previous studies. Conclusions: We accurately determined the δ^18O and Δ^17O values of tropospheric O3 by blank correction using our new method. Measurements of Δ^17O(O3)term of the ambient troposphere showed 1.1 ± 0.7‰ diurnal variations between daytime (higher) and nighttime (lower) due likely to the formation of the temperature inversion layer at night.}, title = {Determination of the triple oxygen isotopic composition of tropospheric ozone in terminal positions using a multistep nitrite‐coated filter‐pack system}, volume = {35}, year = {2021} }