Designation:D2914−15(Reapproved2022)StandardTestMethodsforSulfurDioxideContentoftheAtmosphere(West-GaekeMethod)1ThisstandardisissuedunderthefixeddesignationD2914;thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginaladoptionor,inthecaseofrevision,theyearoflastrevision.Anumberinparenthesesindicatestheyearoflastreapproval.Asuperscriptepsilon(´)indicatesaneditorialchangesincethelastrevisionorreapproval.ThisstandardhasbeenapprovedforusebyagenciesoftheU.S.DepartmentofDefense.1.Scope1.1Thesetestmethodscoverthebubblercollectionandcolorimetricdeterminationofsulfurdioxide(SO2)intheambientorworkplaceatmosphere.1.2ThesetestmethodsareapplicablefordeterminingSO2overtherangefromapproximately25µg/m3(0.01ppm(v))to1000µg/m3(0.4ppm(v)),correspondingtoasolutionconcen-trationof0.03µgSO2/mLto1.3µgSO2/mL.Beer’slawisfollowedthroughtheworkinganalyticalrangefrom0.02µgSO2/mLto1.4µgSO2/mL.1.3Thelowerlimitofdetectionis0.075µgSO2/mL(1),2representinganairconcentrationof25µgSO2/m3(0.01ppm(v))ina30-minsample,or13µgSO2/m3(0.005ppm(v))ina24-hsample.1.4Thesetestmethodsincorporatesamplingforperiodsbetween30minand24h.1.5Thesetestmethodsdescribethedeterminationofthecollected(impinged)samples.AMethodAandaMethodBaredescribed.1.6MethodAispreferredoverMethodB,asitgivesthehighersensitivity,butithasahigherblank.ManualMethodBispH-dependent,butismoresuitablewithspectrometershavingaspectralbandwidthgreaterthan20nm.NOTE1—Thesetestmethodsareapplicableatconcentrationsbelow25µg/m3bysamplinglargervolumesofairiftheabsorptionefficiencyoftheparticularsystemisfirstdetermined,asdescribedinAnnexA4.NOTE2—Concentrationshigherthan1000µg/m3canbedeterminedbyusingsmallergasvolumes,largercollectionvolumes,orbysuitabledilutionofthecollectedsamplewithabsorbingsolutionpriortoanalysis.1.7ThevaluesstatedinSIunitsaretoberegardedasstandard.Nootherunitsofmeasurementareincludedinthisstandard.1.8Warning—Mercuryhasbeendesignatedbymanyregu-latoryagenciesasahazardousmaterialthatcancauseseriousmedicalissues.M...
