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; ${\epsilon }_{\text{a}}={\epsilon }_{\text{n}}{\chi }_{\text{s}}{\chi }_{\text{v}}{\chi }_{\text{a}}$. The signal is a function of the product $q_{\text{v}}{\epsilon }_{\text{a}}$, but ${\epsilon }_{\text{a}}$ is also a function of $q_{\text{v}}$, usually decreasing at high volume rates.