LAUSR

Abstract Nitrogen dioxide (NO2) is a harmful gas with impacts on human health. Human exposure to this pollutant causes an inflammatory response of the respiratory system and increased susceptibility to pulmonary infections. NO2 also promotes the formation of nitrosamines, some of which are potentially carcinogenic. Bus drivers are chronically exposed to potentially high levels of NO2 during their working hours. The objective of this study was to compare the NO2 exposure of urban bus drivers (target group) with that of office workers (control group) during working hours. This is an observational study of a population comprising 59 people, of which 30 were bus drivers (50.8%) and 29 were administrative workers (49.2%). All participants used a passive NO2 sampler that was only exposed while the participant was working. The data were collected over three-week sampling campaigns, one in winter (from June 28, 2017, to July 20, 2017) and the other in summer (from January 3, 2018, to January 24, 2018), in Caxias do Sul, Brazil. For control purposes, NO2 levels were also measured at three different city locations, one directly affected by traffic emissions (traffic station), the second far from these emissions (background station), and the third in the bus parking garage. In general, the results showed that the exposure of bus drivers to NO2 was significantly higher than that of administrative workers P