Understanding the local and remote source contributions to ambient O3 during a pollution episode using a combination of experimental approaches in the Guadalquivir valley, southern Spain

The Guadalquivir Valley is one of three major O3 hotspots in Spain. An airborne and surface measurement campaign was carried out from July 9th to 11th, 2019 to quantify the local/regional O3 contributions using experimental approaches. Air quality and meteorology data from surface measurements, a microlight aircraft, a helium balloon, and remote sensing data (TROPOMI-NO2-ESA) were used to obtain the 3D distribution of O3 and various tracer pollutants. O3 accumulation over 2.5 days started with inputs from oceanic air masses transported inland by sea breezes, which drew O3 and its precursors from a local/regional origin to the northeastern end of the basin. The orographic–meteorological setting of the valley caused vertical recirculation of the air masses inside the valley that caused the accumulation by increasing regional background O3 concentration by 25–30 ppb. Furthermore, possible Mediterranean O3 contributions and additional vertical recirculation through the entrainment zone of the convective boundary layer also contributed. Using particulate matter finer than 2.5 μm (PM2.5), ultrafine particles (UFP), and black carbon (BC) as tracers of local sources, we calculated that local contributions increased regional O3 levels by 20 ppb inside specific pollution plumes transported by the breeze into the valley, and by 10 ppb during midday when flying over an area with abundant agricultural burning during the morning. Air masses that crossed the southern boundaries of the Betic system at mid-altitude (400–1850 m a.s.l.) on July 10th and 11th may have provided additional O3. Meanwhile, a decreasing trend at high altitudes (3000–5000 m a.s.l.) was observed, signifying that the impact of stratospheric O3 intrusion decreased during the campaign

Ultrafine particle formation in the inland sea breeze airflow in Southwest Europe

Studies on ultrafine particles (diameter < 100nm) and air quality have mostly focused on vehicle exhaust emissions and on new particle formation in "clean" ambient air. Here we present a study focused on the processes contributing to ultrafine particle concentrations in a city (Huelva, SW Spain) placed close to a coastal area where significant anthropogenic emissions of aerosol precursors occur. The overall data analysis shows that two processes predominantly contribute to the number of particles coarser than 2.5 nm: vehicle exhaust emissions and new particle formation due to photo-chemical activity. As typically occurs in urban areas, vehicle exhaust emissions result in high concentrations of black carbon (BC) and particles coarser than 2.5 nm (N) during the morning rush hours. The highest N concentrations were recorded during the 11:00-17:00 h period, under the sea breeze regime, when low BC concentrations were registered and photochemical activity resulted in high O3 levels and in new particle formation in the aerosol precursors' rich inland airflow. In this period, it is estimated that about 80% of the number of particles are linked to sulfur dioxide emissions. The contributions to N of "carbonaceous material and those compounds nucleating/condensing immediately after emission" and of the "new particle formation processes in air masses rich gaseous precursors (e.g. SO2)" were estimated by means of a relatively novel method based on simultaneous measurements of BC and N. A comparison with two recent studies suggests that the daily cycles of "new particle formation" during the inland sea breeze is blowing period seem to be a feature of ultrafine particles in coastal areas of South-west Europe. © 2010 Auhtor(s)

The geochemical evolution of brines from phosphogypsum deposits in Huelva (SW Spain) and its environmental implications

The present study focuses on the geochemistry of large phosphogypsum deposits in Huelva (SW Spain). Phosphogypsum slurry waste from fertiliser production was disposed in large ponds containing aqueous waste (i.e. brines) and exposed to weathering. These evaporation ponds were found to be dynamic environments far from attaining steady state conditions where a number of trace pollutants are subjected to temporal variations in response to changing environmental conditions. Chemical, mineralogical and morphological data were used to improve our understanding on the dynamics of a large number of elements in the phosphogypsum-brine-evaporation deposits system. Weekly sampling of brines over the course of 1 yr indicated a substantial enrichment in potentially harmful elements (e.g. As, Cr, Cu, F, Ni, U, V, Zn) present in time-dependent concentrations. The evaporation deposits formed multi-layered precipitates of chlorides, sulphates, phosphates and fluorides containing a large number of pollutants in readily soluble forms. The precipitation sequence revealed a time-dependent composition reflecting alternating precipitation and re-dissolution processes associated with seasonal changes in the local weather conditions. Concatenation of precipitation/re-dissolution stages was found to progressively enrich the brines in pollutants. These findings were supported by the observations from a tank experiment simulating the phosphogypsum-brine-evaporation deposits system under laboratory conditions. Given the substantially high concentrations of pollutants present in mobile forms in the brine-salt system, actions to abate these compounds should be implemented.This study was supported by the Spanish Autonomous Government and the Ministry of Economy and Competitiveness of Spain (Project CGL2014-54637-P; BES-2015-071239). We would like to thank the analytical staff at IDAEA-CSIC for their assistance. We would also like to acknowledge the Generalitat de Catalunya (AGAUR 2015 SGR33) for its support

Measurements and simulation of speciated PM2.5 in south-west Europe

Chemically speciated concentrations of PM2.5 (sulphate, ammonium, nitrate, elemental and organic carbon) were simulated in south-west Europe using the three-dimensional air quality model CAMx driven by the MM5 meteorological model. The inner domain covered the south-west region of Spain with a high spatial (2 km 2 km) and temporal resolution (1 h). The simulation results were evaluated against experimental data obtained in four intensive field campaigns performed in 2008 and 2009 at urban and rural sites. PM2.5 measurements of secondary inorganic compounds and carbonaceous aerosol plus a suite of major and trace elements were determined. High time resolution (10 min) measurements of Black Carbon (BC) were also conducted. The model captured the variability in the ammonium concentrations in both summer and winter periods, although it tended to underestimate the magnitude of concentrations, while for sulphate the performance was better during the summer periods. Particulate ammonium nitrate was only simulated in significant concentrations in the wintertime campaign. This was found to be consistent with the measured composition of PM2.5 where most of nitrate (79e94%) and a significant fraction of sulphate (24e37%) were estimated to be present as non-ammonium salts. These non-ammonium nitrate salts were attributed to the formation of NaNO3. The model PM2.5 primary elemental carbon simulations, evaluated with hourly resolution, captured the diurnal and seasonal variability of PM2.5 BC concentrations at the urban site while poorer performance was observed at the rural site. A large underestimation was observed for simulated PM2.5 organic carbon concentrations during all campaigns. Scenarios of pollution events linked to emissions from south-west Spain, shipping and contributions from more distant emission sources such as Portugal were identified. These results highlight how the distinct features of PM2.5 composition in southern Europe regions, such as the large contribution of non-ammonium salts, need to be taken into account both in model evaluation and in future implementation of aerosol modelling systems

Understanding the local and remote source contributions to ambient O3 during a pollution episode using a combination of experimental approaches in the Guadalquivir valley, southern Spain

The Guadalquivir Valley is one of three major O3 hotspots in Spain. An airborne and surface measurement campaign was carried out from July 9th to 11th, 2019 to quantify the local/regional O3 contributions using experimental approaches. Air quality and meteorology data from surface measurements, a microlight aircraft, a helium balloon, and remote sensing data (TROPOMI-NO2-ESA) were used to obtain the 3D distribution of O3 and various tracer pollutants. O3 accumulation over 2.5 days started with inputs from oceanic air masses transported inland by sea breezes, which drew O3 and its precursors from a local/regional origin to the northeastern end of the basin. The orographic–meteorological setting of the valley caused vertical recirculation of the air masses inside the valley that caused the accumulation by increasing regional background O3 concentration by 25–30 ppb. Furthermore, possible Mediterranean O3 contributions and additional vertical recirculation through the entrainment zone of the convective boundary layer also contributed. Using particulate matter finer than 2.5 μm (PM2.5), ultrafine particles (UFP), and black carbon (BC) as tracers of local sources, we calculated that local contributions increased regional O3 levels by 20 ppb inside specific pollution plumes transported by the breeze into the valley, and by 10 ppb during midday when flying over an area with abundant agricultural burning during the morning. Air masses that crossed the southern boundaries of the Betic system at mid-altitude (400–1850 m a.s.l.) on July 10th and 11th may have provided additional O3. Meanwhile, a decreasing trend at high altitudes (3000–5000 m a.s.l.) was observed, signifying that the impact of stratospheric O3 intrusion decreased during the campaign.The present work was supported by the Spanish Ministry for Ecological Transition (17CAES010); the “Agencia Estatal de Investigación” from the Spanish Ministry of Science, Innovation and Universities and FEDER funds under the project HOUSE (CGL2016-78594-R); the Agencia Estatal de Investigación (RTI2018-095937-B-I00); and the Generalitat de Catalunya (AGAUR 2017 SGR41). We would like to thank the Junta de Andalucía for providing us with air quality data, and the Spanish Met Office (AEMET) for providing meteorological data and facilitating staff and instrumentation for the soundings, as well as ESA for providing TROPOMI-NO2 data and NOAA for the HYSPLIT modeling tool. Cristina Carnerero thanks “Agencia Estatal de Investigación” for the grant received to carry out her PhD (FPI grant: BES-2017-080027). Carlos Pérez García-Pando acknowledges support by the AXA Research Fund, and the Spanish Ministry of Science, Innovation and Universities (RYC-2015-18690).Peer reviewe