## 3 Results and Discussion
\begin{table}
\begin{tabular}{c c c c c c} \hline \hline \multirow{2}{*}{**Family**} & \multirow{2}{*}{**Name**} & \multicolumn{2}{c}{**Months (1–6)**} & \multicolumn{2}{c}{**Odor Threshold**} & \multirow{2}{*}{**Reference**} \\  & & **Alperujo** & **Orujo** & **ppmv** & \\ \hline
**Aldehydes** & 2-furanacarboxaldehyde, 5-methyl-3-Cyclopentene-1-acetaldehyde, 2-oxo-9-Octadecenen & 1,3,4 & 1 & 3.0 & [PERSON] et al. [16] \\  & 2-FORMANCE-1-acetaldehyde, 2-oxo-9-9-Octadecen & 1,3 & 1–3 & & \\  & 9-Octadecen & 3,4 & & \(>\)1.0 & [PERSON] et al. [17] \\  & 2-Leadaldehyde & 1–6 & 1–6 & 0.35–3.5 & [PERSON] et al. [18] \\  & 1-6 & 1–6 & 3.0–23.0 & [PERSON] et al. [18] \\  & 1-6 & 1–6 & 3.0–23.0 & [PERSON] [19] \\  & 1-6 & 1–6 & 0.28 & [PERSON] [19] \\  & 1-6 & & 0.34 & [PERSON] [19] \\  & 1-6 & & 0.01 & [PERSON] [19] \\
**Amides** & Propanamide, 2-hydroxy-2-6 & 1–6 & & \\
**Anines** & Pyridine, 3-ethyl-2-3 & 2–3 & & \\
**Phenonic alcohols** & 2-Meta-hydroxy-4-vinylphenol & 2-3 & 1–6 & 0.003 & [PERSON] [19] \\  & 3-tert-Butyl-4-hydroxyanisole & 2-6 & 2–3 & & \\  & 1-6 & 1–6 & 0.0056 & [PERSON] [19] \\  & 1-6 & 1–6 & 0.0056 & [PERSON] [19] \\  & Phenol, 2-methoxy-4-(1-propenyl)-2-5 & 1–6 & & \\  & Phenol, 2-6-dimethoxy-1-2 & 1–2 & 1 & \\  & Phenol, 4-ethyl-2-methoxy-1-5 & 1–6 & & \\  & 5-tert-Butylpyogalil & 2-3 & 2-3 & & \\
**Aliphatic alcohols** & 1-Dodecanol, 3,7,11-trimethyl-1-1-0 odecanol, 3,7,11-trimethyl-1-1-Hexadecanan, 2-methyl-1-1-2-5 & 2–5 & \\  & 1-Hexadecan, 2-methyl-3-Nonen-1-ol, (E)-2-3 & & & \\
**Aromatic HCs** & 2-furanac methanol & 1–6 & 1-6 & 8.0 & [PERSON] [20] \\  & 1-6 & 1-6 & 0.33 & [PERSON] [19] \\
**Esters** & 10-Octadecen acid, methyl ester & 2-3 & & \\  & Hexanoic acid, 2-phenylethyl ester & 2-6 & & \\
**Carboxylic acids** & Acetic acid & 1–6 & 1–6 & 0.0060 & [PERSON] [19] \\  & 1-Propanoic acid & 4-5 & 0.0057 & [PERSON] [19] \\  & 9-Hexadecenoic acid & 1-6 & & \\
**Aliphatic HCs** & 1-Decene & 3–6 & 5–6 & & \\  & 2-Octene & & 4–5 & 99.808 & odourthreshold. \\  & 8-Heptadecene & 5 & 3–6 & & \\  & 1-6 & 1–6 & 1.5 & [PERSON] [19] \\  & 1-6 & 1–6 & 2.2 & [PERSON] [19] \\  & 1-6 & 1–6 & 1.7 & [PERSON] [19] \\  & 1-6 & 1–6 & 1.6 & 1.7 & [PERSON] [19] \\  & Tetradecane, 2,6,10-trimethyl-1-4-Pentalidene & 2-3 & 1–2 & & \\
**Ketones** & 1,2-Cyclopentaned, 3-methyl-5-3 & 2 & & & \\  & 2-Cyclopenten-1-one, 2-hydroxy-3-methyl-1-6 & 4-5 & & \\  & 2-Cyclopenten-1-one, 2-methyl-3-6 & 1–6 & & \\  & 2-Propanome, 1-acetyloxy-2-6 & 4-5 & 1-6 & & \\
**Ehers** & Octane, 1-methoxy-2-6 & 5 & & \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Selected VOCs detected during the drying process for alperujo and orujo samples. temperature in the drying system is increased, consequently increasing their environmental impact. Results were in agreement with those found by [PERSON] et al. [11], in which the emissions produced in the combustion of olive oil solid waste were mainly hydrocarbons, such as ethane, propane, hexane, toluene, benzene as well as pyridinic derivatives and polycyclic aromatic hydrocarbons. This demonstrates that the most frequent molecules in Table 3 were representative of the emissions during the thermal-mechanical drying of these wastes. It is worth mentioning that a limited number of references were found regarding the odor threshold concentration for the compounds emitted from alperujo and orujo drying, highlighting that further research is needed to complete that gap. Fortunately, odor thresholds of those compounds found as representative of alperujo and orujo emissions during waste drying have been previously reported (Table 3). In addition to the factors that influenced the drying process, VOCs found in the exhaust gases were also related to the prior storage stage as reported previously. Firstly, [PERSON] et al. [3] and [PERSON] et al. [23] showed that there are still a number of important oils (4.0% and 5.7%) in olive oil solid waste prior to drying. Secondly, [PERSON] et al.