Journal of the Chilean Chemical Society
versión On-line ISSN 0717-9707
RUBIO, MARIA A; SANCHEZ, KAREN y LISSI, E. OZONE LEVELS ASSOCIATED TO THE PHOTOCHEMICAL SMOG IN SANTIAGO OF CHILE: THE ELUSIVE ROL OF HYDROCARBONS. J. Chil. Chem. Soc. [online]. 2011, vol.56, n.2, pp. 709-711. ISSN 0717-9707. http://dx.doi.org/10.4067/S0717-97072011000200019.
Santiago of Chile presents, in autumn and summer, high levels of oxidants and, in particular of ozone. Peculiar features of this phenomenon are a strong dependence of the contamination with the daily maxima temperature and a weekend effect, comprising relatively high ozone levels in spite of reduced emissions of its precursors. A common explanation of these effects could be an increase in the VOCs/NOx ratio. In order to test this possibility we perform la multiparametric analysis of Santiago's historical data. This data treatment corroborates a robust dependence of maxima ozone levels with temperature and a moderate weekend effect. In fact, ozone levels in weekend days are similar to those of working days, in spite of significantly reduced primary emissions (29 % of NOx and 20 % of CO). However, no increase in VOCs/NOx ratios, measured at the early morning rush out hours, is observed in high temperature days. On the other hand, the data suggest a moderate increase of the VOCs/NOx ratio in week ends. This would indicate that other factors beyond a simple increase in VOCs levels contribute to the above mentioned peculiarities of oxidant levels in the urban atmosphere of Santiago.
Palabras clave : Ozone; Santiago of Chile; VOCs/NOx ratio; weekend effect.