# How to make units bold in math environment using siunitx package?

I am trying to write a unit for decibel (dB) inside a math environment using siunitx package and I cannot figure out how to make it bold.

I understand that instead of using siunitx package and math mode I can just write dB, but I want to figure out how to do it this way.

I have tried \boldmath and \boldsymbol{} but none of them are working.

Here is my code.

\begin{table}[h!]
\centering
\begin{tabular}{SS}
\toprule
\multicolumn{2}{c}{\textbf{Permissible Noise Exposures}}\\
\toprule
%\rowcolor{clc!50}
\textbf{Duration per Day (in hours)} & \textbf{Sound Level (in \boldmath $\si{dB}$ \footnotemark)} \\
\midrule
8 & 90 \\
6 & 92 \\
4 & 95 \\
3 & 97 \\
2 & 100 \\
1 & 105 \\
0.5 & 110 \\
$\mathtt{\leq}$0.25 & 115 \\
\bottomrule
\end{tabular}
\caption{Permissible Noise Exposures}
\subcaption*{Source: 29 CFR 1910.95, Table G-16}
\label{tab:noise-exposure}
\end{table}\bigskip
\footnotetext{When measured on the A scale of a standard sound level meter at slow response.}


And this is the output. Notice that the dB symbol is not bolded.

I suggest you add the option detect-weight to the \si, \SI, and \num instructions. The option informs siunitx that it should utilize information about the font weight of the surrounding material; if that font weight happens to be bold, it'll be applied to the arguments of \si, \SI, and \num.

For more information about utilizing font-related information from the commands' surrounding material, see section 5.2, "Detecting fonts", of the package's user guide.

\documentclass{article}
\usepackage{siunitx}
\begin{document}
\textbf{Sound Level (in \si{dB})}

\textbf{Sound Level (in \si[detect-weight]{dB})}
\end{document}

• Thank you so much! This completely answeres my question! – Vladimir Jun 10 at 1:11