What causes the old book smell?

I have a collection of old books (all 80+ years old), recently, I received a British Chemistry text from 1903 (intro page below) - this being the oldest book of my collection (112 years old at the time of writing this question): 


![enter image description here](https://i.stack.imgur.com/mEFTN.jpg)


One thing I notice is that there is a distinct smell that comes from the pages of older books. (the smell is not unpleasant) - it seems that the older the book, the more distinct the smell.


**What is the chemistry behind the old pages in a book smell?**




This is a very interesting question. Provided that the materials used in making papers aren't the same around the globe, this is a very broad case of study. However, a study has been conducted in which the main goal was to identify the compounds that are the cause of the smell; [VOCs](https://en.wikipedia.org/wiki/Volatile_organic_compound):[1]



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> Volatile organic compounds (VOCs) are organic chemicals that have a high vapor pressure at ordinary room temperature. Their high vapor pressure results from a low boiling point, which causes large numbers of molecules to evaporate or sublimate from the liquid or solid form of the compound and enter the surrounding air.
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So, quoting the article:



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> Using supervised and unsuper-vised methods of multivariate data analysis, we were able to quantitatively correlate volatile degradation products with properties important for the preservation of historic paper: rosin, lignin and carbonyl group content, degree of polymerization of cellulose, and paper acidity. 
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> It is a result of the several hundred identified volatile and semi-volatile organic compounds (VOCs) off-gassing from paper and the object in general. The particular blend of compounds is a result of a network of degradation pathways and is dependent on the original composition of the object including paper substrate, applied media, and binding. 
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> ![](https://i.stack.imgur.com/oknKB.png)![](https://i.stack.imgur.com/JWOYS.png)
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> The 15 most abundant VOCs present in all chromatograms were selected for further analyses: **acetic acid, benzaldehyde, 2,3-butanedione, butanol, decanal, 2,3-dihydrofuran, 2-ethylhexanol, furfural, hexadecane, hexanal, methoxyphenyloxime, nonanal, octanal, pentanal,** and **undecane**.
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1. [Strlič, M., Thomas, J., Trafela, T., Cséfalvayová, L., Kralj Cigić, I., Kolar, J., Cassar, M. (2009). Material degradomics: on the smell of old books. Analytical Chemistry **2009,** *81* (20), 8617-8622.](http://pubs.acs.org/doi/abs/10.1021/ac9016049)
The main link to the article might be behind a paywall, so for the interested, the relevant [ResearchGate article is accessible](http://www.researchgate.net/publication/26818853_Material_Degradomics_On_the_Smell_of_Old_Books).


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