Consumer spray products are a major category of indoor aerosol particle sources. To provide a quantitative basis for modeling respiratory deposition of indoor aerosol particles, the hygroscopicity of six kinds of consumer spray product particles was studied. It was found that their hygroscopicity varied significantly depending on the nature of the products, with some showing significant hygroscopic growth, some showing moderate hygroscopic growth, and some that were not hygroscopic at all. The particle growth ratios ranged from 1.0 to more than 3.0. A semi-empirical model was used to evaluate the hygroscopic growth of the different kinds of particles. These results could provide the input data needed for a lung deposition model to predict the effect of hygroscopic growth on particle regional deposition and related health effects.