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Thoughts on a GAW program for Global Long Term Measurements of Volatile Organic Compounds

Thoughts on a GAW program for Global Long Term Measurements of Volatile Organic Compounds. Jan W Bottenheim Science and Technology Branch Environment Canada. We all can agree that it is important We all have probably clear ideas how to do it Yet

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Thoughts on a GAW program for Global Long Term Measurements of Volatile Organic Compounds

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  1. Thoughts on a GAW program forGlobal Long Term Measurements ofVolatile Organic Compounds Jan W Bottenheim Science and Technology Branch Environment Canada

  2. We all can agree that it is important • We all have probably clear ideas how to do it Yet • There have been numerous measurement comparison studies • The results are mixed • There has been a plan to make a GAW WCC, which has had one go since 1995 • There is a plan for a demonstration network, written in 1995….

  3. A GAW network needs clear objectives • What does it desire to measure • What are theDOQs, etc, to make it useful • What should be the geographic distribution

  4. It also needs to be doable • Limited list of compounds • Technically feasible • Canister sampling? • One central laboratory, or • Strong intercomparison progam between laboratories • One common set of standards (see ethyne comparison later on) • Buy-in from national programs

  5. Example from Canadian efforts • Environment Canada has 2 active laboratories: ETC-Ottawa (1) and STB-Toronto (2) • (1) sampling at many locations urban and rural • (2) does insitu sampling at one research station (CARE), North of Toronto; canisters for (1) are collected at CARE • (2) collects canisters at GAW station Alert, that are analyzed by (1); • Similarly (2) collects canister samples during the occasional iuntensive field studies, that are then analyzed by (1)

  6. How often do (1) and (2) compare? • NOMHICE, mid 1990s • GAW VOC intercomparison, 2003 Should we compare?

  7. Ambient air, during “clean air” episode (most mixing ratios < 0.1 pptv)

  8. but • Insitu measurements are in danger of being discontinued because of lack of funding (and interest…) • The canister measurements are mostly geared towards identifying the presence of compounds (“toxics” such as aromatics and other solvents are a priority) • Has problems with mixing ratios < 100 pptv -> large uncertainties • Mostly for trends in urban-suburban areas

  9. So to repeat • A GAW plan has to be simple (alkanes are possible, alkenes probably not, OVOCs probably not (?) • Requires buy-in

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