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We recommend the following preservation procedures, holding times and conditions when submitting air samples for testing by the National Measurement Institute (NMI). Please treat these recommendations as a guide only.

TestContainerPreservation procedure (treatment after collection until arrival at NMI)Holding time (maximum time from collection until analysis)Reference
Volatile organic compounds (VOC)canisternil30 daysUS EPA TO15
VOCtubecool to <4 °C30 daysUS EPA TO17
VOCtube, passive samplercool to <4° C14 daysUS EPA 8260
Sulphur compoundscanisternil72 hoursNMI method
Metalsimpinger solutions, filterscool to ≤6 °C30 daysUS EPA M29, US EPA MIO-3.1
Metals (general including CrVI)filters/sorbentscool to ≤6 °C30 days (14 days for CrVI)US EPA 3060A
Sulphate (H2SO4/SO3/SO2)impinger solutions, filtersnilnot availableAPHA 4110B, US EPA M8
Polycyclic aromatic hydrocarbons (PAH)XAD resin, filter, rinsecool to 4 °C, dark 7 daysCARB429
Nitrate (NOx)impinger solution, filternil4 daysAPHA 4110B, US EPA M7A
Fluoride (HF/F2), chloride (HCl/Cl2), bromide (HBr/Br2)impinger solution, filternilnot availableAPHA 4110B, US EPA 26
Formaldehydesilica gel tubecool to <4 °C14 daysUS EPA TO11
Dioxins (PCDD/PCDF)XAD resin, filter, rinsecool to <4 °C30 daysUS EPA M23, US EPA 1613
Dioxins (PCDD/PCDF)PUF tube, filterscool to <4 °C30 daysUS EPA TO-9A, US EPA 1613
Dioxin-like polychlorinated biphenyl (PCB)XAD resin, filter, rinsecool to <4 °C30 daysUS EPA M23, US EPA 1668
Dioxin-like PCBPUF tube, filterscool to <4 °C30 daysUS EPA TO-9A, US EPA 1613
Chlorobenzenes, chlorophenolsXAD resin, filter, rinsecool to <4 °C7 daysUS EPA 8270
Semi-volatile organicsXAD tubecool to <4 °C7 daysUS EPA 8270
Ammoniaimpinger solutionsnilnot availableAPHA 4500-NH3G
Hydrocarbonscanisterambient30 daysMassDEP APH
OCP/OPP/PCBPUF tubecool to <4 °C7 daysUS EPA 8081, US EPA 8141
PAHXAD Tubecool to <4 °C7 daysUS EPA 8270
PAHPUF tube, filterscool to <4 °C7 daysUS EPA TO-13A
Particulate matter (gravimetric analysis)dust filternilnot availableAS 3580.9.10, AS 3640, US EPA M5
PCBXAD or PUF tubecool to <4 °C7 daysUS EPA 8081
Permanent gasescanistersambient30 daysASTM D1946


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Last updated: 13 September 2019

Content ID: 64627