Assessment on the Ozone Air Pollution in a Medium Metropolitan Area: Seville (Spain)

Problems caused by the air pollution which are generated mainly in metropolitan areas and industrial complexes, become in the major challenges for the current society. The air pollution has its origin in the chemical species emission into the atmosphere which may be harmful for human health (Lin, et al., 2008; Doherty et al., 2009), vegetation and ecosystems (Cape, 2008). The pollutants in the atmosphere can be classified in primary, directly emitted to the atmosphere, or secondary, formed in the atmosphere from chemical or photochemical reactions. Nowadays, the main air pollution problems are originated by secondary chemical species, as particles and surface ozone (Kumar et al., 2010; Lefohn et al., 2010). In Europe, there are several Directives to protect air quality, as the Directive 2008 which defines the new threshold for different pollutants. Generally, the highest concentrations of secondary species are registered in areas far away from the emissions sources, as suburban and rural areas. Nevertheless, there are urban areas that due to both meteorological and emissions conditions can suffer high levels of secondary substances (Papanastasiou and Melas, 2009; Alvim-Ferraz et al., 2006). In many countries there are air quality networks which measure concentrations both primary (NO, CO, SO2) and secondary pollutants and provide air quality information in real-time. However, in spite of the elevated economic cost of these networks, it is usual that the collected data are only used to determinate if a pollutant exceed the legal threshold according to the current Directive. Nevertheless, with the information obtained in the air quality networks is possible to carry out studies in order to improve the understanding of the atmospheric pollution and to help in the definition of plans and control strategies to the air quality. The work presented in this chapter is linked with a secondary pollutant, surface ozone, using data from an air quality network in a sensible region suitable to photochemical pollution problems. The study has been carried out in the Seville metropolitan area (low