Given the significant increase in air emissions from mobile
sources, associated with an increased number of gasoline vehicles,
especially diesel vehicles, as well as the use of lower vehicle
technology in urban centers, this study collaborates in the
management of air quality supporting the diagnosis of the study
area and the Metropolitan Area of Porto Alegre. Therefore, this
study aimed to measure ambient particle number concentration
(PNC) and the particle number distributions (PND) in the urban
area of Porto Alegre, Rio Grande do Sul, Brazil. Different locations
in the city, such as urban background, roadsides, traffic
intersections, and street canyon were considered in order to
evaluate different traffic conditions. Measurements were carried
out at the sites during a cold and a warm period.