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OverviewOverview

IntroductionBackground

Where/how the samples were

collectedMethodology

Comparing the three datasets

Coefficient of VariationResults

Conclusion

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IntroductionIntroduction

Airborne sample collection 1000 feet and below

Ground grid study

Comparison between data Confirmation

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BackgroundBackgroundThere were three

separate samplecollections

A first flight on July 22nd

A second flight on July

24th

Grid was predetermined by

Melissa Yang, Ph.D.o Roughly 25 miles between

centers of each boxo Designed to match up with

previous grid studieso All samples taken away

from possible sources(roads, tractors, etc.)

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BackgroundBackground

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MethodologyMethodology

Samples wereanalyzed in theRowland/Blake Labusing gaschromotography

Two systems wereutilized: the bigsystem and themethane system

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MethodologyMethodology

Data filtered 1500 feet

Data was included where the three

sampling campaigns overlappedIntroduction of error

Data from the dairy and vineyardwere discarded

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Actual Data

Used

All datacollectedduringSARP 2009

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MethodologyMethodology

Correlation Average concentrations

Coefficient was too high

Dominating concentrations

Needed a different way to look at howthe data varied

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MethodologyMethodology

Made the decision to compare theconcentrations separately

Calculated standard deviations from

average concentrations Standard deviation inaccurate

Used the coefficient of variationinstead

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Results: Coefficients ofResults: Coefficients of

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CCl4All Data

Flight

Flight

Grid

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PropeneAll Data Flight

Flight Grid

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ResultsResults

Of all thegases, 9 havea coefficient

of variationgreater than.4

Shorterlifetimes

Seinfeld, John. "Global Atmospheric Chemistry of ReactiveHydrocarbons." Reactive hydrocarbons in the atmosphere. Ed. C. N.

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Further WorkFurther Work

Attempt to compare datasets thatoverlay better (though this isdifficult when dealing with

airplanes)Do a comparison between

datasets that is more specificgeographically or temporally

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Questions?Questions?

Thank you!