## 7 Summary of MIR Gas Sensing
\begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline
**Species** & **Bands** & **Wavelength/nm** & **Laser Type** & **Techniques** & **LOD \({}^{1}\)/ppb** & **Refs** & **Applications** \\ \hline \multirow{6}{*}{\(v_{1}\)} & \multirow{2}{*}{3392} & \multirow{2}{*}{ICL} & \multirow{2}{*}{WMS-2f} & \multirow{2}{*}{4800.1 s} & \multirow{2}{*}{[8]} & \multirow{2}{*}{\begin{tabular}{c} \begin{tabular}{c} \begin{tabular} \end{tabular} \\ \end{tabular} } \\ \cline{3-4} \cline{6-7}  & & 3392 & & & & \\ \cline{2-7}  & & & & & & \\ \cline{2-7}  & & 3451.9 & DFG & & & & \\ \cline{2-7}  & & & & & & & \\ \cline{2-7}  & & 3291 & & & & & \\ \cline{2-7}  & & & & & & & \\ \cline{2-7}  & & & & & & & \\ \cline{2-7}  & & & & & & & \\ \cline{2-7}  & & 3300 & & & & & \\ \cline{2-7}  & & 3240 & & & & & \\ \cline{2-7}  & & & & & & & \\ \cline{2-7} CH\({}_{4}\) & \(v_{3}\) & & & & & & & \\ \cline{2-7}  & & 3366 & & & & & & \\ \cline{2-7}  & & 3260 & QW-DFB-DL \({}^{4}\) & PAS;WMS & \(1.5\times 10^{4}\)@12 s & [201] & Environmental \\ \cline{2-7}  & & 3200 & DFG & FCS & 60@80 ms & [202] & Atmospheric \\ \cline{2-7}  & & 3250 & DROPO \({}^{5}\) & FCS & 4@15 ms & [203] & \\ \cline{2-7}  & & 3390 & OPO & FCS & / & [204] & \begin{tabular}{c} Technique \\ research \\ \end{tabular} \\ \cline{2-7}  & & 3270 & OPO & NICE-OHMS \({}^{6}\) & 0.09@20 s & [205] & \begin{tabular}{c} Ultrasensitive \\ detection \\ research \\ \end{tabular} \\ \cline{2-7}  & & & & & & & \\ \cline{2-7}  & & & & & & \\ \cline{2-7}  & & & & & & \\ \cline{2-7}  & & & & & & \\ \cline{2-7}  & & & & & & \\ \hline \multirow{6}{*}{\(C_{2}\)H\({}_{6}\)} & \multirow{2}{*}{\(v_{10}\)} & \multirow{2}{*}{3340} & \multirow{2}{*}{ICL} & \multirow{2}{*}{CLADS \({}^{7}\)} & \multirow{2}{*}{60 ppb@100 s} & \multirow{2}{*}{[141]} & \multirow{2}{*}{\begin{tabular}{c} Technique \\ research \\ \end{tabular} } \\ \cline{2-7}  & & & & & & \\ \cline{2-7}  & & 3330 & & & & \\ \cline{2-7}  & & & & & & \\ \cline{2-7}  & & 3340 & & & & \\ \cline{2-7}  & & & & & & \\ \cline{2-7}  & & & & & & \\ \cline{2-7}  & & 3360 & & LD & WMS & 0.13@1 s & [207] & Environmental \\ \cline{2-7}  & & & & LD & WMS-2f & 0.24@1 s & [208] & \begin{tabular}{c} Technique \\ research \\ \end{tabular} \\ \cline{2-7}  & & & & & & & \\ \hline \multirow{2}{*}{\(C_{2}\)H\({}_{4}\)} & \multirow{2}{*}{\(v_{1}\)} & \multirow{2}{*}{3266} & \multirow{2}{*}{ICL} & \multirow{2}{*}{WMS-2f} & \multirow{2}{*}{53@24 s} & \multirow{2}{*}{[64]} & Industrial \\  & & & & & & & \\ \cline{2-7}  & & & & & & & \\ \hline \multirow{2}{*}{\(C_{2}\)H\({}_{2}\)} & \multirow{2}{*}{\(v_{4}\)\({}_{*}\)\(v_{5}\)} & \multirow{2}{*}{7263} & \multirow{2}{*}{EC-QCL} & \multirow{2}{*}{WMS-2f} & \multirow{2}{*}{3@110 s} & \multirow{2}{*}{[53]} & \multirow{2}{*}{\
\begin{tabular}{c} Exhaled breath \\ analysis \\ \end{tabular} } \\ \hline \multirow{2}{*}{\(C_{3}\)H\({}_{8}\)} & \multirow{2}{*}{\(v_{2}\)} & \multirow{2}{*}{3370.4} & \multirow{2}{*}{ICL} & \multirow{2}{*}{WMS-2f} & \multirow{2}{*}{460@1 s} & \multirow{2}{*}{[209]} & \multirow{2}{*}{
\begin{tabular}{c} Leakage \\ monitoring \\ \end{tabular} } \\ \cline{2-7}  & & & & & & \\ \cline{2-7}  & & 3356 & & & & \\ \cline{2-7}  & & & & & & \\ \cline{2-7}  & & & & & & \\ \cline{2-7}  & & & & & & \\ \cline{2-7}  & & & & & & \\ \cline{2-7}  & & & & & & \\ \cline{2-7}  & & & & & & \\ \hline \multirow{2}{*}{H\({}_{2}\)CO} & \multirow{2}{*}{\(v_{1}\)} & \multirow{2}{*}{3599} & \multirow{2}{*}{ICL} & \multirow{2}{*}{WMS-2f} & \multirow{2}{*}{1.5@140 s} & \multirow{2}{*}{[216]} & Atmospheric \\  & & & & & & & \\ \cline{2-7}  & & & & & & & \\ \cline{2-7}  & & & & & & & \\ \cline{2-7}  & & & & & & & \\ \cline{2-7}  & & & & & & & \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Summary of single component detection by MIR spectroscopy (2008–2018).