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% --- skin palette: resin amber, terracotta clay, bitumen brown -------------
\definecolor{resin}{HTML}{A9691F}
\definecolor{resindeep}{HTML}{7C4A12}
\definecolor{clay}{HTML}{B1502C}
\definecolor{bitumen}{HTML}{3C2A1A}
\definecolor{smoke}{HTML}{7C7060}

\title{What Nine Egyptian Mummies Actually Smell Like}
\author{The Science Journaling Club}
\date{Field Notes --- Paper Analysis --- Heritage Science}

\begin{document}
\maketitle

\begin{abstract}
A smell has never had a fixed procedure. In February 2025 a team led by Emma
Paolin, working across University College London, the University of
Ljubljana, Kraków University of Economics, and the Egyptian Museum in Cairo,
gave it one anyway. They put nine mummified human bodies --- five held in
storage, four standing in gallery display cases, spanning the New Kingdom to
the Byzantine period --- through non-invasive headspace sampling, gas
chromatography-mass spectrometry with olfactometry (GC-MS-O), and a trained
sensory panel scoring thirteen fixed descriptor words \cite{paolin2025}. The
three words that came back most often were \emph{woody} (in 78\% of the
bodies), \emph{spicy} (67\%), and \emph{sweet} (56\%) --- a chemical
signature of cedar and juniper resin, myrrh, and degraded wood that has sat
in these bodies for roughly three thousand years. Underneath it the
instrument also found compounds nobody embalmed on purpose: a botanical
pest-control oil the museum applies to display cases, unexplained synthetic
pesticide residues, and volatile by-products of mould and bacteria still
metabolizing on the wrappings today. This Field Note is a close read of the
method, the compound list, and the paper's own ethics section on what it
means to study, and publish, the smell of a body that cannot consent to
being smelled. \textbf{The conversion of one of the paper's reported odor
thresholds into an everyday volume of air is ours}, computed from their
published numbers and flagged as such throughout.
\end{abstract}

%============================================================================
\section{Nine Bodies, One Instrument Nobody Had Pointed at Them}

Every museum with an Egyptological collection has always known its
mummified bodies have a smell. Curators mention it, conservators work
around it, and visitors ask about it in a way that makes clear they expected
something worse, or something better. None of that is data. A smell
described only in conversation cannot be compared across a room, a museum,
or a century of conservation treatments, because there is no shared
vocabulary and no instrument reading behind any of it.

The 2025 study fixes that gap for nine specific bodies in the Egyptian
Museum in Cairo, chosen to span two conservation histories: five kept in
storage, largely undisturbed, and four standing in gallery display cases
that the museum actively treats against insect damage \cite{paolin2025}. The
bodies range from the New Kingdom, more than three thousand years old,
through the Late Period and into the Byzantine era of Roman Egypt. Table
\ref{tab:specimens} reproduces the paper's own table of the nine bodies.

\begin{table}[htbp]
\centering
\small
\begin{tabular}{lllr}
\toprule
\textbf{Body} & \textbf{Location} & \textbf{Period} & \textbf{Condition (0--8)} \\
\midrule
M1 & storage & not reported & 5 \\
M2 & storage & New Kingdom, c.\ 1539--1077 BCE & 4 \\
M3 & storage & Byzantine, 3rd--4th c.\ CE & 5 \\
M4 & storage & not reported & 3 \\
M5 & storage & not reported & 0 \\
M6 & gallery & Late Period, c.\ 664--332 BCE & 4 \\
M7 & gallery & Late Period, c.\ 664--332 BCE & 6 \\
M8 & gallery & Late Period, c.\ 664--332 BCE & 2 \\
M9 & gallery & New Kingdom, 1292--1077 BCE & 8 \\
\bottomrule
\end{tabular}
\caption{The nine mummified bodies as tabulated in the anchor paper, with
location, archaeological period where reported, and conservation condition
on the paper's own 0 (worst) to 8 (best) scale \cite{paolin2025}. Gallery
bodies M6--M9 were last treated with a pest-control oil in 2021 (M6--M8) or
2023 (M9); storage bodies carry no such treatment record.}
\label{tab:specimens}
\end{table}

The question the team asked was not ``does it smell bad.'' It was narrower
and more answerable: what specific volatile molecules leave these bodies,
and does a trained human nose describe those molecules the same way a
chemist's instrument would sort them?

%============================================================================
\section{Why a Smell Needed Two Separate Instruments}

A gas chromatograph-mass spectrometer is extraordinarily good at telling
you what molecules are present in a sample and roughly how much of each. It
is completely indifferent to whether any of them smell like anything.
Chemical abundance and perceptual importance are not the same axis, and a
paper that only ran a standard GC-MS would have a compound list with no way
to say which entries actually built the smell a visitor perceives.

The fix, standard in flavour and fragrance chemistry since at least the
1960s, is to route the column's output to two detectors at once: the mass
spectrometer, which identifies the molecule, and a sniffing port, where a
trained human describes what just eluted at that exact retention time
\cite{zellner2008}. That combined technique is gas chromatography-
olfactometry, GC-MS-O for short --- the only way to know, of the dozens of
compounds a chromatogram reports, which handful are actually doing the
smelling.

The paper's GC-MS-O work ran as four replicate analyses per mummified body,
split across two institutions, Kraków University of Economics and the
University of Ljubljana \cite{paolin2025}. At each institution a trained
assessor sits at the sniffing port as separated compounds elute one by one
and records, in real time, a quality descriptor, an intensity, and a
pleasantness rating for each. Matching the two data streams by retention
time gives a compound with a name and a smell attached to it at once.

\begin{figure}[htbp]
\centering
\begin{tikzpicture}[
  box/.style={draw, minimum width=4.4cm, minimum height=1cm, align=center, font=\footnotesize},
  arr/.style={-{Stealth[length=2mm]}}
]
\node[box, fill=resin!12] (head) at (2.2,7) {headspace inside\\the coffin or case};
\node[box, draw=resin, minimum width=2.6cm] (spme) at (0.2,5.4) {passive: SPME fibre};
\node[box, draw=resin, minimum width=2.6cm] (sorb) at (4.2,5.4) {active: sorbent tube};
\node[box, draw=resin, minimum width=6.6cm] (gcmso) at (2.2,3.7) {GC-MS-O, 4 replicate runs/body\\Kraków Univ.\ of Economics + Univ.\ of Ljubljana};
\node[box, draw=resin, minimum width=3.1cm] (ms) at (0.4,1.9) {mass spectrometer:\\molecule identity};
\node[box, draw=resin, minimum width=3.1cm] (nose) at (4.0,1.9) {trained sniffer:\\quality, intensity, pleasantness};
\node[box, draw=smoke, minimum width=2.2cm, minimum height=1.4cm] (panel) at (-3.2,3.7) {sensory panel:\\13 fixed words,\\0--10 intensity,\\whole sample};
\draw[arr] (head) -- (spme);
\draw[arr] (head) -- (sorb);
\draw[arr] (spme) -- (gcmso);
\draw[arr] (sorb) -- (gcmso);
\draw[arr] (gcmso) -- (ms);
\draw[arr] (gcmso) -- (nose);
\draw[arr, dashed, smoke] (head) -| (panel);
\node[font=\scriptsize, align=center] at (2.2,0.6) {matched by retention time: a named, odor-active compound};
\end{tikzpicture}
\caption{The two measurement tracks run on the same headspace air: an
independent trained sensory panel scoring the whole sample, and instrumented
GC-MS-O identifying and describing individual odor-active molecules.
Redrawn from the method description in \cite{paolin2025}, not a reproduction
of a published figure.}
\label{fig:tracks}
\end{figure}

%============================================================================
\section{Getting the Air Without Touching Anyone}

Every sampling step avoided physical contact with the remains. Two
complementary headspace techniques did the work. Solid-phase
microextraction (SPME) is passive: a fibre coated in an absorbent polymer
is suspended in the air inside the coffin or case and left to equilibrate,
pulling volatile molecules onto its surface simply by sitting there.
Sorbent-tube sampling is active: a small pump draws a measured volume of
that same air through a tube packed with adsorbent material, trapping
compounds as the air passes \cite{paolin2025}. Running both against the
same headspace lets the analysis cross-check itself rather than trusting one
extraction chemistry alone. Nothing in this protocol opens a wrapping,
touches a body, or removes material from the remains: the signal is
entirely airborne.

%============================================================================
\section{Thirteen Words, and Which Three Kept Coming Back}

The sensory side of the study worked from a fixed vocabulary of thirteen
descriptors, developed and agreed on in training: spicy, woody, mouldy,
stale/rancid, sweet, ethereal, resin-like, citrus-like, floral, dusty,
herbal, incense-like, and smoky \cite{paolin2025}. For each body the panel
rated how strongly each applicable descriptor applied, scored overall
intensity on a 0-to-10 scale, and rated hedonic tone. Average perceived
intensity across the set came out medium, with body M3 the least intense,
and average hedonic tone was rated slightly pleasant.

\begin{figure}[htbp]
\centering
\begin{tikzpicture}
\begin{axis}[
  width=13cm, height=6.5cm,
  xbar, y dir=reverse,
  xmin=0, xmax=100,
  xlabel={\% of the nine bodies carrying the descriptor},
  symbolic y coords={stale-rancid, incense-like, sweet, spicy, woody},
  ytick=data,
  yticklabels={{stale, rancid}, incense-like, sweet, spicy, woody},
  nodes near coords, nodes near coords align={horizontal},
  bar width=12pt,
  ymajorgrids=false, xmajorgrids=true, grid style={dashed, gray!30}
]
\addplot[fill=resin, draw=resindeep] coordinates {
  (78,woody) (67,spicy) (56,sweet) (33,incense-like) (33,stale-rancid) };
\end{axis}
\end{tikzpicture}
\caption{The five most frequent sensory descriptors across the nine
mummified bodies, as reported in \cite{paolin2025}. Woody, spicy and sweet
each appeared in a clear majority of the set.}
\label{fig:descriptors}
\end{figure}

%============================================================================
\section{Woody, Spicy, Sweet: What the Chemistry Behind Each Word Actually Is}

A descriptor word is not an explanation until it is tied back to a
molecule, and this is where GC-MS-O earns its keep. The largest compound
category by far traces directly to the embalming process and to what has
happened to it since. A family of terpenoid compounds --- $\alpha$-pinene,
d-limonene, l-verbenone, borneol --- points to the resins the embalmers
used: cedar, pine and juniper resins, myrrh, and frankincense, long
documented as embalming ingredients and naturally rich in exactly these
terpenes \cite{paolin2025, buckley2001}. That family accounts for most of
the woody, spicy, and resin-like descriptors the panel assigned. Two
lactones, $\gamma$-decalactone and $\gamma$-octalactone, gave a distinctive
sweet, fruity note and were detected uniquely in body M9 --- the same body
carrying the highest conservation condition score in the set. Degradation
adds its own layer: acetic acid and furfural mark ongoing breakdown of wood
and cellulose, 2(5\emph{H})-furanone and vanillin are classic markers of
lignin breaking down over time, and benzoic acid, octanoic acid, $p$-cresol
and $(E)$-cinnamaldehyde round out the list. A set of phenolic compounds
turned up specifically in the display-case air rather than in storage
\cite{paolin2025}.

None of this required the chemists to guess: terpenoid and lactone
signatures like these are well characterized in the archaeological-
chemistry literature on mummification balms, going back to foundational
GC-MS work on embalming agents recovered directly from wrapped tissue
\cite{buckley2001}. What is new here is not the chemistry of the resin ---
it is putting a trained nose on the same air and confirming that the
compounds a mass spectrometer reports are the same compounds a human being
would independently call ``woody'' and ``sweet.''

%============================================================================
\section{The Compounds That Have Nothing To Do With Ancient Egypt}

Three further categories showed up, and none came from the embalming
workshop. The Egyptian Museum treats its display cases with a natural
pest-control oil --- a blend of clove, camphor, peppermint, basil, lemon,
orange and cinnamon oils, applied to protect displayed bodies from insect
damage \cite{paolin2025}. That treatment leaves eugenol, octanol, and more
$\alpha$-pinene, this time from clove and camphor rather than resin.
Separately, and without a documented treatment record explaining it, the
four gallery bodies also carried synthetic pesticide residues, identifiable
by mass spectrometry but for the most part odorless at the concentrations
found. Finally, live biology: octanal, nonanal, and a cluster of
eight-carbon compounds including 1-octen-3-ol and 3-octanol --- volatiles
from actively metabolizing fungi and bacteria, matched by microbiological
swab testing to species including \textit{Aspergillus niger},
\textit{Penicillium chrysogenum}, \textit{Cladosporium cladosporioides},
and several \textit{Bacillus} species \cite{paolin2025}. The stale/rancid
descriptor used in a third of the bodies traces to this fourth category,
not to the mummy itself.

\begin{table}[htbp]
\centering
\small
\begin{tabular}{p{2.6cm}p{2.4cm}p{7.2cm}}
\toprule
\textbf{Category} & \textbf{Origin} & \textbf{Representative compounds} \\
\midrule
1. Resin \& degradation & c.\ 3,000 yr old & $\alpha$-pinene, d-limonene, verbenone, borneol; $\gamma$-decalactone, $\gamma$-octalactone (M9 only); acetic acid, furfural, 2(5\emph{H})-furanone, vanillin, $p$-cresol \\
2. Museum pest oil & applied 2021--23 & eugenol, octanol, $\alpha$-pinene (clove/camphor source); only on M6--M9 \\
3. Synthetic pesticide & undocumented & residues in M6--M9, identified by MS, mostly odorless \\
4. Microbial VOCs & living, ongoing & octanal, nonanal, 1-octen-3-ol, 3-octanol; \textit{A.\ niger}, \textit{P.\ chrysogenum}, \textit{C.\ cladosporioides}, \textit{Bacillus} spp. \\
\bottomrule
\end{tabular}
\caption{The four volatile-compound categories identified in the study,
with representative compounds \cite{paolin2025}. Only category 1 originates
in the mummification itself.}
\label{tab:categories}
\end{table}

Location in the museum is not incidental to category. Pest oil and the
unexplained pesticide residues both track bodies M6--M9, the ones on
display and the ones the museum actively treats; storage bodies M1--M5
carry neither. Category 1 is universal, intrinsic to what was done to the
body rather than to where it has since been kept. The paper reports more
generally that displayed bodies showed greater variety and higher
concentration of compounds overall than storage bodies, attributed to
volatiles accumulating inside semi-enclosed display cases. A hierarchical
cluster analysis of the full chemical profiles grouped the nine bodies by
archaeological period, conservation treatment, and material composition ---
the chemistry alone sorting itself along lines an archaeologist would
recognize \cite{paolin2025}.

%============================================================================
\section{Club Arithmetic: How Faint Is Faint?}
\label{sec:arithmetic}

What follows is ours, computed from the paper's published numbers rather
than quoted from it. The paper reports odor detection thresholds (ODTs) for
the two lactones unique to M9: $\gamma$-decalactone at 0.005--0.01 parts per
million, and $\gamma$-octalactone at 0.01--0.02 parts per million
\cite{paolin2025}. A part per million by volume is the ratio of the volume
of vapour to the total volume of air, times $10^{6}$:
\begin{equation}
\mathrm{ppm} = \frac{V_{\text{solute}}}{V_{\text{total}}} \times 10^{6}.
\end{equation}
Rearranged for the total volume that dilutes a fixed droplet down to a
stated threshold,
\begin{equation}
V_{\text{total}} = \frac{V_{\text{solute}}}{\mathrm{ppm}/10^{6}}.
\end{equation}

Take a single microlitre of $\gamma$-decalactone, $V_{\text{solute}} =
10^{-6}$~L, smaller than a raindrop. At the low end of its threshold range,
0.01~ppm, $V_{\text{total}} = 10^{-6}/10^{-8} = 100$~L. At the high end,
0.005~ppm, $V_{\text{total}} = 200$~L --- close to the volume of a standard
55-gallon drum. The same conversion on $\gamma$-octalactone's range,
0.01--0.02~ppm, gives 50--100~L. A trained panellist's nose is doing
chemistry at the scale of drops in drums, not drops in bathtubs.

\begin{figure}[htbp]
\centering
\begin{tikzpicture}
\begin{axis}[
  width=12cm, height=5.5cm,
  xbar, y dir=reverse,
  xmin=0, xmax=220,
  xlabel={litres of air, 1 $\mu$L diluted to threshold},
  symbolic y coords={gamma-octalactone, gamma-decalactone},
  ytick=data,
  yticklabels={{$\gamma$-octalactone}, {$\gamma$-decalactone}},
  bar width=16pt,
  ymajorgrids=false, xmajorgrids=true, grid style={dashed, gray!30}
]
\addplot[fill=resin!45, draw=resindeep] coordinates {
  (200,gamma-decalactone) (100,gamma-octalactone) };
\addplot[fill=resin, draw=resindeep] coordinates {
  (100,gamma-decalactone) (50,gamma-octalactone) };
\end{axis}
\end{tikzpicture}
\caption{Our own conversion of the paper's published odor detection
thresholds into an everyday volume: how much air a single microlitre
droplet of each lactone can be diluted into and still sit at the reported
detection threshold \cite{paolin2025}. Dark segment: the tighter (lower ppm)
end of the reported range. Not the paper's own framing.}
\label{fig:threshold}
\end{figure}

%============================================================================
\section{Whose Nose, and Whose Consent}

The paper does not treat ethics as an afterthought; it is built into the
title and argued through directly. The authors state that ``any study of
human remains necessitates consideration of ethical implications, given
their significance to the originating communities'' \cite{paolin2025}. A
mummified body is not simply an old chemistry sample --- it is a person, and
decisions about how that person's remains are studied, displayed, and, in
this case, smelled by strangers carry a weight that a jar of ancient resin
does not.

The paper situates itself inside a longer tension in museum practice:
increased public scrutiny has pushed heritage scholars toward a balance
between respecting the human body and giving visitors a genuinely
informative experience, and the authors note that other recent studies of
human remains have provoked mixed public reactions, which is exactly why
communicating the ethical framework a study operates under matters as much
as the results \cite{paolin2025}. That tension has its own literature
outside this paper: whether, and how, museums should display human remains
at all has been argued directly by heritage researchers for close to two
decades \cite{alberti2009}.

Two design choices read as direct responses to that tension. Nothing about
the sampling touches the remains: headspace air, not tissue, wrapping, or
bone. And the study explicitly involves local stakeholders --- workers at
the Egyptian Museum in Cairo --- rather than treating the collection purely
as a resource for outside researchers, which the authors frame as
supporting the ``social sustainability'' of the heritage in question
\cite{paolin2025}.

%============================================================================
\section{What the Paper Actually Recommends Museums Do}

A study like this earns its ethics section by turning findings into
practice, in four concrete ways \cite{paolin2025}. First, a health and
safety finding: identifying synthetic pesticide residues on display bodies
means specific handling guidelines can be written for staff, and bodies
carrying such residues could be placed in separate display arrangements.
Second, an argument for treating the smell itself as heritage worth
preserving deliberately --- ``the olfactory heritage should be preserved as
an integral part of the mummified body's significance.'' Third, a specific
storage recommendation: keeping mummified bodies in display cases rather
than loose wrapping, since the case moderates how volatiles accumulate and
disperse. Fourth, a data-management point: systematically archiving the
chemical and olfactory data collected here in repositories, so future
conservators and researchers can compare against it rather than starting
from nothing.

%============================================================================
\section{Where the Method Still Has Gaps}

A trained sensory panel is still a small number of trained people, and the
paper does not report exactly how many sat on it, which makes it hard to
independently judge how much any one person's vocabulary shaped the shared
descriptor list. The synthetic pesticide residues are flagged and
identified but the paper does not explain, because it likely cannot from
chemistry alone, when or by whom they were applied --- a gap in the
museum's own conservation records rather than a limitation of the
analytical method. And the four categories are not perfectly separable in
practice: $\alpha$-pinene turns up in both the ancient resin and the modern
pest oil, so a single detected peak cannot always be assigned to one source
with certainty without the surrounding context of which other compounds
accompany it. None of this undermines the central result; it is the
ordinary residue of doing archaeological chemistry on a sample that has
been sitting in an active museum, absorbing whatever that museum has done
to it, for a very long time.

%============================================================================
\section{What Stays With Us}

The plainest way to say what this paper does is: it took something everyone
in the room already knew --- that these bodies have a smell --- and built an
instrument path from that private sensory fact to a shared, citable,
chemically grounded one. Woody, spicy, sweet is not a poetic flourish. It
is what $\alpha$-pinene, verbenone, and a pair of lactones actually smell
like to a trained nose, confirmed independently by a mass spectrometer that
has no opinion about poetry at all. Underneath that three-thousand-year-old
signature sits a second, much younger one: clove oil from 2021, pesticide
nobody has a record of applying, and fungi that are, right now, still
metabolizing. A museum case is not a sealed vessel. It has its own
chemistry, made partly by the people who work there today, and this paper
is one of the first times anyone pointed an instrument at all of it at
once.

%============================================================================
\begin{thebibliography}{9}

\bibitem{paolin2025}
Paolin, E., Bembibre, C., Di Gianvincenzo, F., Torres-Elguera, J.~C., Deraz,
R., Kraševec, I., Abdellah, A., Ahmed, A., Kralj Cigić, I., Elnaggar, A.,
Abdelhalim, A.~M., Sawoszczuk, T. \& Strlič, M. (2025).
Ancient Egyptian Mummified Bodies: Cross-Disciplinary Analysis of Their
Smell. \textit{Journal of the American Chemical Society} 147(8), 6633--6643.
doi:10.1021/jacs.4c15769

\bibitem{zellner2008}
d'Acampora Zellner, B., Dugo, P., Dugo, G. \& Mondello, L. (2008).
Gas chromatography-olfactometry in food flavour analysis.
\textit{Journal of Chromatography A} 1186(1--2), 123--143.
doi:10.1016/j.chroma.2007.09.006

\bibitem{buckley2001}
Buckley, S.~A. \& Evershed, R.~P. (2001).
Organic chemistry of embalming agents in Pharaonic and Graeco-Roman
mummies. \textit{Nature} 413, 837--841. doi:10.1038/35101588

\bibitem{alberti2009}
Alberti, S.~J.~M.~M., Bieńkowski, P., Chapman, M.~J. \& Drew, R. (2009).
Should we display the dead? \textit{Museum and Society} 7(3), 133--149.
doi:10.29311/mas.v7i3.144

\end{thebibliography}

\end{document}