For example, in the simulation where 10 7 initiators correspond to a real reaction concentration of 0.05 mol/L, the steady-state concentration of active radicals can be expressed as [𝑅•] 0 × 10 7 0.05 ≈ 49, which gradually decays over time. Notably, when chain initiation, propagation, and termination occur, the concentration of active radicals fluctuates by ±2. Consequently, the parameter ∑ 𝑁 𝑎 𝑖 of the exponential distribution undergoes significant changes, making it difficult to implement the 𝜏-leaping algorithm. This also explains the necessity of simulating a large number of particles to maintain system stability and avoid the pronounced effects of low radical concentrations. For instance, in a smaller system, the theoretically simulated concentration of active radicals might fall below 1. However, in practical simulations, the concentration must be a non-negative integer, resulting in the number of radicals fluctuating between 0 and 2, which deviates significantly from real reaction behavior.