The present study deals with particle pollution in a particular micro-environment: a French high-speed train smoker car. In the first part, measurements carried out in a real train are described. Both smoker and non-smoker cars’ particle concentrations have been measured during a round trip. Additional experiments have been done in a stationary car with controlled particle pollution to evaluate parameters such as ventilation rates, deposition velocities and filter efficiencies involved in the particle mass balance of the studied zone. In the second part, a one-zone model has been developed to predict the particle concentration in the train car. Particle transport, deposition and filtration phenomena have been estimated from the stationary car experiments considering the well-mixed zone assumption. The model has then been applied to the round trip train to determine the particle concentration during the journey. Results show that the smoker car indoor air quality can be easily improved by changing the usual utilized filter by a high-efficiency H10-type filter, leading to a 34% reduction of the passengers inhaled dose.