Zn-DTPA is a chelator to treat internal radioactive contamination with FDA approval. A jet nebulizer and an ultrasonic nebulizer were used to aerosolize the Zn-DTPA solution. The particle size distribution was measured by a particle time-of-flight analyzer and cascade impactor. Two evaluation parameters, the mass median aerodynamic diameter (MMAD) and geometric standard deviation (GSD), were used to assess whether the aerosols can reach the lower respiratory tract. The results showed that increasing the filling volume of Zn-DTPA solution would decrease the MMAD and GSD. Overall, a rising concentration also raised the MMAD. The deposition fractions of different stages of the cascade impactor reflected the particle size distribution of aerosols. A specific setup was designed considering the influence from temperature and humidity to the measurement of particle size distribution. The experimental results suggest that the Zn-DTPA aerosols are detectable in the cascade impactor with a flow rate of 60 L/min.