Spatial and temporal variation of the impact of an extreme Saharan dust event

The impact on PM10, meteorology and visibility of the severe Saharan dust outbreak registered in Europe in October 2008 is evaluated in detail in mainland Spain and the Balearic Islands. Data from a large number of air quality stations (261), METAR observations at 39 airports, besides records from meteorological networks, were used. Information from dispersion models, satellite observations, synoptic charts and back-trajectory analysis, supported the interpretation. During the event, 89% of the monitoring stations exceeded the daily limit value. The highest daily averaged PM10 concentration across Spain ranged from 378 to 18 mu g m(-3), following a hyperbolic decay with increasing latitude. An opposite relationship between visibility and PM10 was found for data at 12 UTC. The strength of the episode may be related to strong subsidence at low levels over the Iberian Peninsula.