Part of what makes ATom fun is just flying over the open ocean,
and it's interesting just to see how
you know, we're trying to sample chemistry in remote
regions, but when you go on these flights, you really see that there
aren't many places that humans have not yet impacted.
We live and breathe in the atmosphere and
even though it seems quite inert, it's a really dynamic medium
and there's a lot of chemistry going on, so it's just something I've
always been interested in; I've always been interested in spectroscopy,
and how you can use lasers to make these really incredibly specific
and sensitive measurements. I'm working on the in situ airborne
formaldehyde instrument, which is an instrument that measures formaldehyde
in the atmosphere. Our instrument on the plane is literally a
black box, with a couple of switches.
I don't know, it's not that exciting to look at, but
on the inside, it's pretty fun.
We have an inlet on the window of the airplane, and our instrument pulls in air through
this inlet in a series of tubes, into our detection cell, where the laser
passes through and then the formaldehyde in that
sample will absorb and re-emit photons and the
re-emitted photons are what we measure and detect as formaldehyde.
So we actually count the number of photons and so on our screen, we can
read the number of counts per second or per unit time
and if we see the counts go up, it means we have a lot of formaldehyde and
and if we see the counts go down, it means we have less. So when we're flying,
on ATom, formaldehyde can be pretty low, because we're flying over
kind of remote open ocean, but when we fly into
air parcels that are continental outflow,
we'll see elevated formaldehyde, and this
can be from biomass burning or from
any like human-caused activity, so
formaldehyde is an indication of oxidation chemistry, and we care about
oxidation because it will tell us, let's say the
rate at which methane gets oxidized, and methane is a
very potent greenhouse gas, and we'd like to be able to better understand
methane's lifetime as the climate changes.