The measurement guidelines for VOCs are currently under development in collaboration with the ACTRIS (Aerosols, Clouds and Trace Gases Research Infrastructure) network (). A standard operating procedure for taking air samples with stainless steel canisters is available in WMO (2012). General recommendations on VOC measurements can be found in WMO (2007). Regular GAW VOC workshops review the status of VOC measurements in the GAW Programme () and provide further guidance on the development of techniques, quality assurance and gas standards. Table 16.1. List of the priority VOCs in the GAW Programme Lifetime (assuming Steel Glass Analysis Molecule OH concentration Importance to GAW flaska flask methodb is 106 cm–3) ✓ ✓ 1. Ethane 1.5 months – Source of methane GC-FID – Natural sources – Biomass burning – Fossil fuel – Ocean production (southern hemisphere) – Trend in size of seasonal cycle – Indicator of halogen chemistry ✓ ✓ 2. Propane 11 days – Source of methane GC-FID – Natural sources – Biomass burning – Fossil fuel – Ocean production (southern hemisphere) ✓ ✓ 3. Acetylene 15 days – Motor vehicle tracer GC-FID – Biomass burning tracer – Ratios to the other hydrocarbons – Trends 4. Isoprene 3 hours – Biosphere product ? ? GC-FID PTR-MS – Sensitive to temperature/land – Used for climate change – O3 precursor – Oxidizing capacity – Precursor to formaldehyde 5. Formaldehyde 1 day – Indicator of isoprene oxidation – – DOAS – Biomass burning – Comparison with satellites – Trends 6. Terpenes 1–5 hours – Precursors to organic aerosols – – GC-MS PTR-MS
The measurement guidelines for VOCs are currently under development in collaboration with the ACTRIS (Aerosols, Clouds and Trace Gases Research Infrastructure) network (). A standard operating procedure for taking air samples with stainless steel canisters is available in WMO (2012). General recommendations on VOC measurements can be found in WMO (2007). Regular GAW VOC workshops review the status of VOC measurements in the GAW Programme () and provide further guidance on the development of techniques, quality assurance and gas standards. Table 16.1. List of the priority VOCs in the GAW Programme Molecule Lifetime (assuming OH concentration is 106 cm–3) Importance to GAW Steel flaska Glass flask Analysis methodb 1. Ethane 1.5 months – Source of methane – Natural sources – Biomass burning – Fossil fuel – Ocean production (southern hemisphere) – Trend in size of seasonal cycle – Indicator of halogen chemistry ✓ ✓ GC-FID 2. Propane 11 days – Source of methane – Natural sources – Biomass burning – Fossil fuel – Ocean production (southern hemisphere) ✓ ✓ GC-FID 3. Acetylene 15 days – Motor vehicle tracer – Biomass burning tracer – Ratios to the other hydrocarbons – Trends ✓ ✓ GC-FID 4. Isoprene 3 hours – Biosphere product – Sensitive to temperature/land – Used for climate change – O3 precursor – Oxidizing capacity – Precursor to formaldehyde ? ? GC-FID PTR-MS 5. Formaldehyde 1 day – Indicator of isoprene oxidation – Biomass burning – Comparison with satellites – Trends – – DOAS 6. Terpenes 1–5 hours – Precursors to organic aerosols – – GC-MS PTR-MS
8_I_16_en_for_EdBd.docx