School students are exposed to the increased particulate (PM) number concentration inside the school bus on daily basis while commuting on urban road networks. However, the potential effect of different ventilation over in-cabin pollutants is still unclear in many aspects. The present paper investigates the influence of varying ventilation scenarios over in-cabin particle number concentration (PNC) and air exchange rates (AERs) inside idle and moving (unoccupied (SB_u) and occupied (SB_o)) school bus. The in-cabin total PNC sharply increased by a factor of 1.53, 1.57 and 1.14 for SB_p, SB_u, and SB_o respectively under windows open (WO) from windows closed (WC) scenarios. In-vehicle student activity and ventilation scenarios were positively correlated with the change in in-cabin PNC. For SB_p, the average estimated AERs are 9.19 h⁻¹ and 3.30 h⁻¹ under WO and WC scenarios respectively whereas, total PNC deposition rate under natural convection condition varied between 2.52 to 6.89 h⁻¹. In the present study, inside-outside measurements were recorded for 10 km long road segment under realistic driving conditions. The average AERs value of SB_u and SB_o are highest for WO (42.40 h⁻¹ and 14.46 h⁻¹) compared to WC (10.91 h⁻¹ and 10.94 h⁻¹) scenarios. A Generalized estimating model (GEE) model was developed and the model suggested that vehicle age, mileage, and speed are the factors positively associated with the AERs estimated for WO and WC scenarios under realistic driving conditions.

在通勤城市道路网络的过程中，学生每天都会暴露在校车内增加的颗粒物（PM）浓度中。但是，在许多方面，不同通风对舱内污染物的潜在影响仍不清楚。本文研究了不同的通风情况对闲置和移动（空载（SB _u）和空载（SB _o））校车内客舱内颗粒物浓度（PNC）和空气交换率（AER）的影响。对于SB _p，SB _u和SB _o，机舱内总PNC急剧增加了1.53、1.57和1.14倍。分别在关闭窗口（WC）方案下的打开窗口（WO）下。车内学生活动和通风情况与车内PNC的变化呈正相关。对于SB _p，在WO和WC情况下，平均估计AERs分别为9.19 h ^-1和3.30 h ^-1，而自然对流条件下的PNC总沉积速率在2.52至6.89 h ^-1之间变化。在本研究中，在实际驾驶条件下记录了10 km长路段的内外测量。与WC（10.91 h）相比，WO（42.40 h ^-1和14.46 h ^-1）的SB _u和SB _o的平均AERs值最高。^-1和10.94 h ^-1）场景。建立了通用估计模型（GEE），该模型表明，在实际驾驶条件下，车辆的年龄，行驶里程和速度是与WO和WC情况下估计的AER呈正相关的因素。