Analysis of the correlations between NO, NO2 and O3 concentrations in Campo Grande – MS, Brazil

Abstract

Ozone (O 3 ) is a secondary gaseous pollutant in the urban environment, and its variation correlates well with nitrogen oxides (NO x = NO + NO 2 ). Continuous monitoring has been done in the Campo Grande city urban area, using ozone 49C and NO-NO 2 -NO x 42CTL gas analyzers. The results show that the maximum concentrations of O 3 and oxidant (O x = O 3 + NO 2 ) in Campo Grande often appear in the early afternoon around 15:00 hours. The daily variation of NO concentrations shows a very clear cycle with two peaks, one appearing around 07:00 a.m. and the other at 11:00 p.m. At the lowest level, NO 2 is the main component of NO x , while NO dominates the higher mixing ratio. It is also shown that the level of O x is composed of two factors: the regional and the local contributions. The former is affected by the regional O 3 level, while the latter is effectively correlated with the primary pollution level. The daily variation also appears in the concentrations of oxidant components.