Measurement of particle number and related pollutant concentrations in an urban area in South Brazil

► Particle number and its association with NO, NO2, NOx, O3 was analyzed. ► Results showed a higher number concentration of the PR2.5 and PR1.0 size ranges. ► Particle number concentration was influenced by emissions from motor vehicles. ► Correlation analysis suggest similar emission sources for NO, NOx and particle number. ► Results indicate influence of meteorological conditions on particle number.