Code
\documentclass{article}
\usepackage[amsmath]
\begin{document}
ionizing collisions is about $132 \, \mu \text{m}$
\end{document}
giving
where I think the $\mu$ should be not cursive. I tried unsuccessfully putting the symbol within the text -environment.
What is the correct environment of the symbol for non-cursive text?


$N_{P} = 27$ ion pairs/cmtoo? – Léo Léopold Hertz 준영 Sep 08 '15 at 12:48ion pair\si{\per\centi\metre}(which is probably how I'd do it). – Chris H Sep 08 '15 at 13:21