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Part of what makes ATom fun is just flying over the open ocean,

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and it's interesting just to see how 

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you know, we're trying to sample chemistry in remote

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regions, but when you go on these flights, you really see that there 

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aren't many places that humans have not yet impacted.

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We live and breathe in the atmosphere and 

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even though it seems quite inert, it's a really dynamic medium

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and there's a lot of chemistry going on, so it's just something I've 

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always been interested in; I've always been interested in spectroscopy,

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and how you can use lasers to make these really incredibly specific

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and sensitive measurements. I'm working on the in situ airborne 

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formaldehyde instrument, which is an instrument that measures formaldehyde

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in the atmosphere. Our instrument on the plane is literally a 

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black box, with a couple of switches.

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I don't know, it's not that exciting to look at, but 

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on the inside, it's pretty fun. 

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We have an inlet on the window of the airplane, and our instrument pulls in air through 

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this inlet in a series of tubes, into our detection cell, where the laser

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passes through and then the formaldehyde in that

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sample will absorb and re-emit photons and the

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re-emitted photons are what we measure and detect as formaldehyde.

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So we actually count the number of photons and so on our screen, we can

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read the number of counts per second or per unit time

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and if we see the counts go up, it means we have a lot of formaldehyde and 

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and if we see the counts go down, it means we have less. So when we're flying, 

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on ATom, formaldehyde can be pretty low, because we're flying over

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kind of remote open ocean, but when we fly into 

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air parcels that are continental outflow, 

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we'll see elevated formaldehyde, and this 

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can be from biomass burning or from 

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any like human-caused activity, so 

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formaldehyde is an indication of oxidation chemistry, and we care about 

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oxidation because it will tell us, let's say the 

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rate at which methane gets oxidized, and methane is a 

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very potent greenhouse gas, and we'd like to be able to better understand 

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methane's lifetime as the climate changes.