It is of great importance to mitigate nanoparticle exposure in the environment by using effective control devices. For controlling nanoparticles with the particle diameter (dp) < 100 nm in the air environment, electrostatic precipitators (ESPs) are widely used in many industries because of their low pressure drop and high removal efficiency. However, existing models cannot predict the nanoparticle collection efficiency very well. This is due to the partial charging effect, when some nanoparticles are not charged but penetrate through the ESPs, resulting in a decrease in the collection efficiency. In this study, a modified Deutsch-Anderson model was developed to predict the nanoparticle collection efficiency (η, %), as well as that for particles with dp > 100 nm. The present model is η(%) = [1 – exp(–A(NDe)B) + C(NDe) – (1 – α)] × 100%, where A, B, and C are regression coefficients, NDe is the modified Deutsch number, and α is the partial charging factor. Good agreement was obtained between the present predictions and experimental data published in the literature. It is expected that the modified equation can facilitate the design and scale-up of the ESPs for controlling nanoparticle emissions, as well as particle in all size ranges.