Air pollution in the plateau of the Iberian Peninsula

To assess the air pollution in the central Iberian Peninsula, NO, NO2, O3, SO2 and PM10 hourly data were collected at eight air quality stations (urban and suburban) belonging to the Air Quality Network of Castilla-La Mancha (Spain) during the 2008-2011 period. Weather conditions and air mass patterns were investigated, and three atmospheric transport patterns were identified. The mean levels of O3, NO2, SO2 and PM10 ranged between 51 and 64, 12 and 25, 2and 7 and 23 and 34 μg m− 3, respectively, although some peaks of O3, SO2 and NO2 exceeded the thresholds defined in the European Directives. Monthly and daily variations showed typical cycles, with SO2 peaks in industrial areas, or high ozone levels in downwind zones strongly affected by traffic emissions. The weekend effect was observed mainly for NO2 and PM10, while there was a low effect for ozone and NO effect for SO2. Dependence of NO, NO2 and O3 with the NOx levels was also investigated through oxidant concentrations OX (O3 + NO2). NOx-independent regional contribution to the oxidant levels showed a strong seasonality and high values. Maximum values of OX concentrations at low levels of NOx were found in areas strongly affected by urban plumes, whereas maximum OX levels at high NOx values indicated the influence of local sources. The studied area can be divided into three groups, that located downwind of strong traffic emissions, that influenced by industrial emissions (in these two zones the main air pollution problems are focused) and finally that group conditioned by local sources.