Ultrafine Particles on Electric, Gas, and Diesel Buses in the Mass Transit Buses of Bogotá, Colombia

The concentration of traffic-related air pollutants (TRAPs) inside transport microenvironments takes on relevance today in many megacities with high population density, intense traffic, and prolonged travel times. These conditions can intensify exposure to TRAPs and worsen public health problems. TRAP concentrations in these microenvironments are changing because of the introduction of cleaner technologies. In this study, we compare the ultrafine particles measured inside diesel, gas, and electric buses during their normal operation in Bogotá, Colombia. We used a miniature diffusion size classifier (DiSCmini) to measure ultrafine particle concentrations, average particle size, and the lung-deposited surface area. Our results revealed significantly lower levels of this pollutant inside electric buses. The concentration of ultrafine particles per cubic centimeter is about 41% and 27% lower in electric buses compared to diesel and gas, respectively. The lung-deposited surface area is also lower in electric buses. Nevertheless, the average particle size in electric buses is 10% and 18% smaller compared to diesel and gas, respectively.