Impact of different vehicle distances on PM2.5 concentration and population exposure from two electric two-wheelers traveling side-by-side.

As a commuting tool, electric two-wheelers are convenient, fast, and environmentally friendly. Electric two-wheelers accounted for more than 75% of all electric vehicles. However, riding electric two-wheelers may generate resuspension dust pollution, which may pose a risk of dust exposure due to directly exposed to the air environment for riders. So it is necessary to study the road dust generated during the electric two-wheelers traveling, and impact of different vehicle distances on PM2.5 concentration and population. Computational fluid dynamics method and sliding mesh technique were used to simulate two electric two-wheelers traveling side-by-side and analyze PM2.5 concentration distribution under different vehicle distances. For d = 1.5 m, the airflow speed was the highest both in front of and in the rear of the vehicle, compared to for d = 0.5 m and 1.0 m. The average PM2.5 concentration decreased with the increase of the height z above the ground, and the average PM2.5 concentrations were the lowest at d = 1.0 m. The average PM2.5 concentration at y = 0 m line was highest for d = 0.5 m and d = 1.5 m and lowest for d = 1.0 m. Regardless of the vehicle distances, the average PM2.5 exposure concentration was highest for carried children compared to carried adult and the drivers. For carried adult, carried child, and the driver, the average PM2.5 exposure concentration within 5 s was lowest for d = 1.0 m. PM2.5 exposure for carried children should be a priority concern in the two electric two-wheelers traveling side-by-side. The vehicle distance of 1.0 m should be maintained to reduce resuspension dust PM2.5 pollution. The research results provide important data support for studying dust distribution during the electric two-wheeler.