Quantifying the Spatiotemporal PM2.5, Black Carbon, and Ultrafine Particle Concentrations Aboard Public Buses in Brazil: A Comparison of Three Cities

Abstract

The transportation environment contributes disproportionately to air pollution exposure, despite the short amount of time spent in this microenvironment. Elevated concentrations of air pollution within bus passenger cabins are often observed. Buses stop frequently at bus stops for passengers to get on and off, as well as typically travel down main roads with high traffic characteristics. These events will facilitate the entry of outdoor air pollution into the bus passenger cabin, resulting in pollutant spikes. There are many negative health effects associated with exposure to PM2.5, black carbon (BC), and ultrafine particles (UFP); three components of air pollution related to vehicle exhaust emissions. This work quantifies the PM2.5, BC, and UFP concentrations aboard buses in three different sized cities in Brazil where transportation air pollution studies are in their infancy. It was found that traffic characteristics contributed to fluctuations in on-board particulate air pollution concentrations.