\mu => \upmu

config.tex

@@ -13,6 +13,8 @@
 \DeclareSIUnit\rms{rms}
 \DeclareSIUnit\rad{rad}
 
+\usepackage{upgreek} % useful for "mu" in units
+
 \usepackage{amssymb}
 \usepackage{amsmath}
 \usepackage{amsthm}

setup.org

@@ -21,6 +21,8 @@
 \DeclareSIUnit\px{px}
 \DeclareSIUnit\rms{rms}
 \DeclareSIUnit\rad{rad}
+
+\usepackage{upgreek} % useful for "mu" in units
 #+end_src
 
 ** Mathematics