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 	\subsection{Scanning Mobility Particle Sizer}
 	\label{methods: subsec: SMPS}
 	
-	The aerosol concentration is measured using a \gls{SMPSa}, which in turn consists of a \gls{DMAa} and a \gls{CPCa}, arranged in series. 
+	The aerosol concentration is measured using a \gls{SMPSa}, which in turn consists of a neutraliser, a \gls{DMAa} and a \gls{CPCa}, arranged in series. The \gls{DMAa} is ramping a time-dependent voltage profile $U(t)$ between its two electrodes. This creates a time-varying electric field of the strength $E\approx U/(d_{o}-d_{i})$ which in turn causes particles within the \gls{DMAa} to experience a drift in this field of velocity $v=Z_{p}E$, where $Z_{p}$ denotes the electrical mobility. 
 	
 	\begin{equation}
 		m_{\textnormal{F}}=\int_{t_{\textnormal{in}}}^{t_{\textnormal{out}}}\gls{MFLOWs}\,\der{t}\approx\sum_{\textnormal{Samples}}\gls{MFLOWs}_{i}\Delta t_{i}