Designation:D1357−95(Reapproved2019)StandardPracticeforPlanningtheSamplingoftheAmbientAtmosphere1ThisstandardisissuedunderthefixeddesignationD1357;thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginaladoptionor,inthecaseofrevision,theyearoflastrevision.Anumberinparenthesesindicatestheyearoflastreapproval.Asuperscriptepsilon(´)indicatesaneditorialchangesincethelastrevisionorreapproval.1.Scope1.1Thepurposeofthispracticeistopresentthebroadconceptsofsamplingtheambientairfortheconcentrationsofcontaminants.Detailedproceduresarenotdiscussed.Generalprinciplesinplanningasamplingprogramaregivenincludingguidelinesfortheselectionofsitesandthelocationoftheairsamplinginlet.1.2Investigationsofatmosphericcontaminantsinvolvethestudyofaheterogeneousmassunderuncontrolledconditions.Interpretationofthedataderivedfromtheairsamplingprogrammustoftenbebasedonthestatisticaltheoryofprobability.Extremecaremustbeobservedtoobtainmeasure-mentsoverasufficientlengthoftimetoobtainresultsthatmaybeconsideredrepresentative.1.3Thevariablesthatmayaffectthecontaminantconcen-trationsaretheatmosphericstability(temperature-heightprofile),turbulence,windspeedanddirection,solarradiation,precipitation,topography,emissionrates,chemicalreactionratesfortheirformationanddecomposition,andthephysicalandchemicalpropertiesofthecontaminant.Toobtainconcen-trationsofgaseouscontaminantsintermsofweightperunitvolume,theambienttemperatureandatmosphericpressureatthelocationsampledmustbeknown.1.4ThevaluesstatedinSIunitsaretoberegardedasstandard.Nootherunitsofmeasurementareincludedinthisstandard.1.5Thisstandarddoesnotpurporttoaddressallofthesafetyconcerns,ifany,associatedwithitsuse.Itistheresponsibilityoftheuserofthisstandardtoestablishappro-priatesafety,health,andenvironmentalpracticesanddeter-minetheapplicabilityofregulatorylimitationspriortouse.1.6Thisinternationalstandardwasdevelopedinaccor-dancewithinternationallyrecognizedprinciplesonstandard-izationestablishedintheDecisiononPrinciplesfortheDevelopment...
