Supplementary material to "Balloon-borne Stratospheric Vertical Profiling of Carbonyl Sulfide and Evaluation of Ozone Scrubbers"

S1 Tests on gas species removal due to O3 scrubbers 5The effects of different O3 scrubbers on COS and O3, tested on tropospheric compressed air, are shown in Fig. S1 andS2.The p-values of the ANOVA test for each species are reported in Table S1 and Table S2.When O3 was not generated, none of the two scrubbers showed significant differences with the bypass channel neither for COS, nor for O3.Clearly, the O3 scrubbing was performed quantitatively by the squalene-based scrubber, while the cottonbased one was likely saturated and could not remove the vast majority of the produced ozone.When O3 was produced in the 10 UV lamp, we measured higher COS molar fractions both with cotton and with squalene.We believe this is due to oxidation of other compounds (e.g., CS2, DMS) in presence of UV radiation, and not due to the scrubbers themselves.The higher uncertainty for the tests with squalene is due to some spectroscopical effects that affected the instrument precision during part of the tests (not shown).Either way, no sign of negative biases on COS was measured for either of the two scrubbers.Figure S1: effects of different ozone scrubbers on COS.Table S1: p-values resulting from the ANOVA test for COS molar fractions in the tracer removal tests.The p-values = 0 are due to a comparison between single measurements, therefore no standard deviation can be computed.COS Bypass channel No O3, squalene No O3, cotton O3 generation, squalene O3generation, cotton Bypass channel 0.792997793 0.192430962 0.036612983 0.0353083 No O3, squalene 0.792997793 0.199969975 0.053576395 0.050245879 No O3, cotton 0.192430962 0.199969975 0.193251053 0.184500858 O3 generation, squalene 0.036612983 0.053576395 0.193251053 0 O3 generation, cotton 0.0353083 0.050245879 0.184500858 0 Table S6: p-values resulting from the ANOVA test for N2O molar fractions.N2O No O3, no scrubber O3 generation, no scrubber No O3, squalene O3 generation, squalene Bypass channel No O3, no scrubber 0.359325384 0.217409312 0.277689103 0.377699683 O3 generation, no scrubber 0.359325384 0.112412874 0.137165062 0.289831556 No O3, squalene 0.217409312 0.112412874 0.761757143 0.972574391 O3 generation, squalene 0.277689103 0.137165062 0.761757143 0.843816095 Bypass channel 0.377699683 0.289831556 0.972574391 0.843816095 Table S7: p-values resulting from the ANOVA test for COS molar fractions (see Fig. A2 in the main text).