ASTMDL704M9507595300555033761AMERICANSOCIET‘IFORTESTINGANDMATERIALS1916RaceSt.Philadelphia,Pa19103ReprintedfromtheAnnualBookofASTMStandardsCopyrightASTMIfnotlistedinthecurrentcombinedindexwillappearinthene>beditionDesignation:D1704M-95METRICStandardTestMethodforDeterminingtheAmountofParticulateMatterintheAtmospherebyMeasurementoftheLightAbsorbanceofaFilterSample[Metric]‘ThisstandardisissuedunderthefixeddesignationD1704M;thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginaladoptionor,inthecaseofrevision,theyearoflastrevision.Anumberinparenthesesindicatestheyearoflastreapproval.Asuperscriptepsilon(e)indicatesaneditorialchangesincethelastrevisionorreapproval.1.Scope1.1Thistestmethodmeasuresafunctionoftheconcen-trationofsuspendedparticulatematterintheambientatmospheresquicklyandinexpensively.Hourlyrepetitivesamplesaretakenautomatically.1.2Thistestmethoddoesnotprovideresultsinmass/volumeunitsbutinamethod-definedunit,dustcoefficientperkm(DJkm),whichisdirectlyrelatedtothesoilingeffectofthesampledatmospherewhendrawnthroughfilterpaper.RelationsbetweenDJkmandmassconcentrationmeasure-mentsaredependentonthenature,sizedistribution,shape,andrefractiveindexoftheparticulatematter.Whenthesefactorsareconstantatonesite,ausefulrelationshipbetweenDJkmandmassconcentrationvaluescanoftenbedevel-oped.1.3Thetestmethodcanaccommodatelowandhighconcentrationsofsuspendedparticulatematterbyalterationofthesamplevolumeviaflowrateorsamplingtimechanges.1.4Thetestmethodisnotapplicablewhenfogormistarepresentinthesampledatmospherebecausewetfilterpaperhasaflowresistancesohighthatthesamplepumpwillnotbeabletodrawsampleairthroughthepaper.1.5Thetransferofthesamplefromtheatmospheretotheinstrumentwillprecipitatesomeoftheparticulatematteronthewailsofthetubingused.Guidelinestominimizethiseffectareincludedbelow,butthetestmethodislimitedtosituationsinwhichashortsamplingline,thatis,lessthan5m,canbeprovided.1.6Theaccuracy,reproducibility,andusefulnessofthisandothertestmethodsformeasurementsofsusp...
