Origin of the exceedances of the European daily PM limit value in regional background areas of Spain

摘要: Abstract The origin of the daily exceedances 50 μg PM10 m−3 (daily limit value or DLV EU air quality directive) and an arbitrary (DV) 35 μg PM2.5 m−3 recorded in 2001–2003 13 regional background stations Iberian Peninsula were interpreted. This was carried out by means back-trajectory analysis, available PM model outputs, satellite data meteorological maps. allows detection high episodes on a scale study their seasonal geographical variability. number PM10 ranged from 6 to 41 depending monitoring site. For selected PM2.5 DV, range 0–10 period. majority (>70% most stations) PM2.5 (17–55% are caused African dust outbreaks. These less frequent winter than summer due to: (a) long transport warm seasons over Iberia, (b) re-suspension associated with convective atmospheric dynamics, (c) relative low rainfall favouring residence time PM. Moreover, contribution secondary aerosols derived efficient photochemical transformation gaseous precursors may coincide summer. Episodes lack advective conditions 2–29% 20–50% exceedances. occurred mainly poor renovation masses, increased re-suspension, dispersion pollutants towards rural areas re-circulation aging masses which result proliferation inorganic species. Long-range continental Europe (9–40% 18–38% exceedances, respectively), only northern Iberia because, as European evolve south, suffer dispersion/dilution. Local advection clean Atlantic cannot increase levels great extent without influence local source proportion 6–33% 17–40%, respectively.