<p>The Lagrangian Particle Dispersion Model is widely utilized in predicting the transport trajectory of air pollutants and reproducing concentration fields to assess pollution levels. Except for the traditional particle concentration calculation method (the Box counting), several alternative particle concentration calculation methods (the Gaussian kernel, the Uniform kernel and the Parabolic kernel) have been investigated. However, the effectiveness of these methods under radionuclide dispersion scenarios has not been sufficiently uniformly evaluated, so evaluating the capabilities of these methods under radionuclide dispersion scenarios is essential for their future applications in nuclear emergency decision-making and nuclear accident assessment. This paper aims to evaluate the capacity of three different particle concentration calculation methods via the Belgian field experiment by coupling the California Meteorological Model and the Lagrangian Particle Dispersion Model. In comparison with the observed values, the simulated results of three methods successfully reproduced parts of the peak values. The results of Gaussian kernel show an overall slight underestimation, while the Uniform kernel and Parabolic kernel display an overall slight overestimation. Furthermore, all three methods basically meet the statistical acceptance criteria. The numerical distributions of Parabolic kernel exhibit the best degree of matching with observations, while these of Uniform are the weakest.</p>