National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Ibaraki, Japan.
Isuzu Motors Ltd, Fujisawa, Kanagawa, Japan.
Indoor Air. 2022 Mar;32(3):e13019. doi: 10.1111/ina.13019.
As COVID-19 continues to spread, infection risk on public transport is concerning. Air exchange rates (ACH) and advection-diffusion of CO and particles were determined in a route bus to evaluate the infection risk. ACH increased with bus speed whether windows were open or closed, and ACH were greater when more windows were open. With two open windows, ACH was greater when a front and rear window were open than when two rear windows were open. With both front and rear ventilation fans set to exhaust, ACH was more than double that when both were set to supply. With air conditioning (AC) off, CO and particles spread proportionally at the same rate from a source, whereas with the AC on, the spread rate of particles was about half that of CO , because particles might be trapped by a prefilter on the AC unit. Infection risk can be reduced by equipping AC unit with an appropriate filter. Calculations with a modified Wells-Riley equation showed that average infection risk was reduced by 92% in the moving bus with windows open comparing to with windows closed. When the bus was moving with windows closed, exhaust fan operation reduced the average risk by 35%.
随着 COVID-19 的继续传播，公共交通工具上的感染风险令人担忧。本研究在路线公交车上测定空气交换率 (ACH) 和 CO 及颗粒的平流扩散，以评估感染风险。无论车窗打开还是关闭，公交车速度增加时 ACH 都会增加，并且打开更多车窗时 ACH 更大。当打开两个车窗时，前后车窗打开时的 ACH 大于两个后车窗打开时的 ACH。前后通风扇都设置为排气时，ACH 是设置为送风时的两倍以上。空调 (AC) 关闭时，CO 和颗粒从源以相同的速度按比例传播，而空调打开时，颗粒的传播速度约为 CO 的一半，因为颗粒可能被空调单元上的预过滤器捕获。通过为 AC 单元配备适当的过滤器，可以降低感染风险。经 Wells-Riley 方程修正后的计算表明，与车窗关闭相比，在行驶的公交车上打开车窗可将平均感染风险降低 92%。当公交车在关闭车窗的情况下行驶时，排气扇的运行可将平均风险降低 35%。
