The
substance fraction of atomized component in the component consumed.
The efficiency of atomization is measured in a given part of the flame, usually the
observation space;

.
The signal is a function of the product

,
but

is also a function of

,
usually decreasing at high volume rates.
Source:
PAC, 1986, 58, 1737
(Quantities and units in clinical chemistry: Nebulizer and flame properties in flame
emission and absorption spectrometry (Recommendations 1986))
on page 1741