[Show abstract][Hide abstract] ABSTRACT: REDMAAS (Red Española de DMAs Ambientales), the Spanish network of environmental Differential Mobility Analyzers (DMAs), currently consists of six research groups involved in the measurement of atmospheric aerosol size distributions by means of DMAs. The aim of this network is to guarantee the good quality and comparability of the routine measurements carried out at each different location and in diverse environments across Spain. In order to reach this objective, one of its main activities is an annual intercomparison of mobility size spectrometers used within the network (five units Scanning Mobility Particle Sizers (SMPS) and one Ultrafine Particle Monitor (UFPM)). Here we report the main results obtained during the 2010-2012
campaigns, including a study on particle deposition in dryers used in ambient air sampling systems. In general, all instruments showed a good performance with deviations in an accepted tolerance. The intercomparisons have been proven to be a useful exercise to detect instrument problems, such as incorrect calibrations. DMA calibration checks were performed with polystyrene latex (PSL) reference particles. Deviations of less than 1% were observed during the first year, which increased to a value of 4.7% during the last campaign. Some differences among the responses of different Condensation Particle Counter (CPC) models were encountered, being mainly connected to the intrinsic characteristics of each counter. The comparison of the UFPM with the CPCs has given good results. The SMPS intercomparisons, especially for particles above 20 nm, have been within +/- 15% tolerances. Regarding the particle deposition in dryers
used in sampling systems, particle penetration was lower than predicted by the recommended model. This result was probably due to the fact that not all the possible mechanisms were considered in the model.
[Show abstract][Hide abstract] ABSTRACT: The chlorophtye Coccomyxa sp. (strain onubensis) growing under either inorganic phosphorus or sulfur starvation showed, unlike other non-extremophile microalgae, the ability to grow still for a period of 2 weeks with retention of high activity of photosystem II, due to P and S reserves in the microalga. Lutein and β-carotene contents slightly increased for a few days in nitrogen-lacking cultures only, with no major impact on productivity due to cease of growth. Maximum fatty acid content of Coccomyxa sp. (strain onubensis) growing in nutrient-lacking culture media accounted for about 13 % of dry biomass and about 50 % of the total lipid fraction, linolenic (C18:3) being the most abundant fatty acid. The lipid content of this microalga is on the average of non-extremophile microalgae, but it has the advantage of producing in highly acidic culture media (pH 2.5, and even lower) which allow its outdoor production-preserving cultures from other microalgae contamination. Nutrient-limited cultures showed a significant increase in the intracellular activity levels of the enzymes glutathione reductase (GR), ascorbate peroxidase (APX) and catalase (CAT), indicating a connection between nutrient deprivation and oxidative stress in Coccomyxa sp. (strain onubensis).
[Show abstract][Hide abstract] ABSTRACT: Day-of-week variations in O3, NOx, CO and PM10 were analysed in the southwestern region of Europe (specifically Andalusia, Spain) using hourly concentrations collected at 43 stations (representing five typologies) over 6 years (2003-2008). This area has air pollution problems, and the study of the weekend effect is used as a tool to plan future strategies for emissions reductions. Maximum daily 8 h averages for O3, daily 90th percentiles for NO, NO2 and PM10 and mean daily values for CO were calculated and used to assess the weekend effect by applying three different metrics: weekly evolution, weekend-weekday differences and average daily difference between weekends minus workdays. Based on daily parameters and weekend-weekday differences, all the measured air pollutants exhibited clearly reduced concentrations (oscillating between 25 to 85%) on weekends, mainly at urban and suburban stations, with the exception of O3 (less than 10 g m-3). This decrease on weekend days was mostly observed for NO, NO2 and PM10 at urban stations, while differences at industrial and rural stations were low or null. CO showed a low reduction. Using the daily cycle of differences (weekend minus workdays) as a reference, positive deviations were observed at night and negative differences were observed during the daytime for NO, NO2 and PM10 at urban traffic, urban background and suburban background sites. A reduction in morning rush hour traffic during the weekends was reflected in the data from urban stations, which showed a decrease of up to 50, 15 and 12 g m-3 for NO, NO2 and PM10, respectively. An opposite daily behaviour was found for ozone, which showed an increase at urban area sites of up to 15 g m-3 in the early morning.
Aerosol and Air Quality Research 07/2014; 14:1862-1874. DOI:10.4209/aaqr.2014.02.0026 · 2.09 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Surface ozone is one of the most important photochemical pollutants in the low atmosphere, causing damage to human health, vegetation, materials and climate. The weather (high temperatures and high solar radiation), orography (presence of the Guadalquivir valley) and anthropogenic (the cities of Cádiz, Córdoba, Huelva and Seville and two important industrial complexes) characteristics of the southwestern Iberian Peninsula make this region ideal for the formation and accumulation of ozone. To increase the knowledge of ozone behaviour in this area, the monthly, daily and weekly variations of ozone and its precursors, nitrogen oxides (NOx = NO + NO2), were analysed over a 4-year period (2003 to 2006). Using the k-means cluster technique, 12 representative stations of five different areas with different ozone behaviour were selected from a total of 29 monitoring sites. This is the first time that the analysis of these atmospheric pollutants has been carried out for the whole area, allowing therefore a complete understanding of the dynamics and the relationships of these compounds in this region. The results showed an opposite behaviour among ozone and NO and NO2 concentrations in urban and suburban zones, marked by maximums of ozone (minimums NOx) in spring and summer and minimums (maximums) in autumn and winter. A seasonal behaviour, with lower amplitude, was also observed in rural and industrial areas for ozone concentrations, with the NO and NO2 concentrations remaining at low and similar values during the year in rural zones due to the absence of emission sources in their surroundings. The daily cycles of ozone in urban, suburban and industrial sites registered a maximum value in the early afternoon (14:00-17:00 UTC) while for NOx two peaks were observed, at 7:00-10:00 UTC and 20:00-22:00. In the case of rural stations, no hourly peak of ozone or NOx was registered. The weekend effect was studied by using a statistical contrast tests (Student's t). The results indicated that only areas influenced by important traffic emissions presented a weekend effect for NO and NO2, whereas an ozone weekend effect was not detected in any case.
[Show abstract][Hide abstract] ABSTRACT: The DOMINO (Diel Oxidant Mechanisms in relation to Nitrogen Oxides) campaign was carried out from 21 November to 8 December 2008 at El Arenosillo station (SW of Spain) in a coastal-rural environment. The main weather conditions are analysed using local meteorological variables, meteorological soundings, synoptic maps, as well as back trajectories of the air masses using the HYSPLIT model and high spatial resolution of meteorological fields. Measurements of the main meteorological parameters were collected both on the surface and on a tall tower. A detailed land use analysis was performed on a 80 km scale showing the main types of vegetation and land use. Also the main anthropogenic atmospheric emission sources both industrial-urban from Huelva and from the urban Seville area are shown. A study to identify air mass origins and their variation with height was carried out. In this intensive campaign air masses coming from different areas with different emission sources were observed: from the NW, with a highly industrial-urban character; continental flows from northerly directions; from the NE, with pathway, first, over the Seville metropolitan area and, then, over the Doñana national park; and maritime air masses coming from the Atlantic Ocean. To study the chemistry in the four atmospheric scenarios identified, gas phase measurements of primary and secondary species such as ozone, NO, NO2 and SO2, biogenic and anthropogenic VOCs like benzene and isoprene, as well as total particles concentration and chemical composition of the aerosols are compared and discussed. The highest levels for total particle concentration, NO, NO2, SO2, benzene, PM10, PM2.5 and chemical elements such as As or Cu were found under flows associated with industrial-urban emissions from the Huelva-Portugal sector which are transported to the site before significant removal by chemical or deposition mechanism can occur. The air masses from the north were affected mainly by crustal elements and biogenic sources, the latter being exemplified by the biogenic species such as isoprene, particularly in the first part of the campaign. The urban air from the Seville area, before arriving at El Arenosillo traverses the Doñana National Park and therefore, was affected by industrial-urban and biogenic emissions. This aged air parcel can transport low levels of NOx, total particle concentration, SO2 as well as ozone and isoprene. Marine air masses from the Atlantic Ocean influence El Arenosillo frequently. Under these conditions the lowest levels of almost all the species were measured with the exception of ozone levels associated to long-range transport.
[Show abstract][Hide abstract] ABSTRACT: Unmaned aerial vehicles (UAVs), popularly know as drones, have been extensively used for many years for military and civil applications. In this experiment, a Meggitt BTT-3 Banshee drone has been used for scientific purposes. This drone is made mostly of Kevlar and glass-reinforced plastic and used a rear rotary engine. The flight will be held at El Arenosillo, which has a large experience flying this and other types of drones. The success and stable conditions of the flight is, therefore, guaranteed.
The drone can be equipped with instrumentation, because it has a cargo bay capable of carrying more than 10 kilograms of payload. The biggest problem to cope with is the strong acceleration during taking-off. It is also important to pay attention to the energy demand of the instrumentation installed on board. These constraints determine the selection of suitable instrumentation. In our case an array spectroradiometer, specifically a StellarNet Black CXR-50 has been chosen as the main instrument. This CCD spectrometer is installed oriented to the zenith and measure global solar downward radiation in 2048 different wavelengths between 270nm and 900nm. This kind of instrument consists in a CCD sensor and a combination of mirrors diffraction grating and filters. All these pieces have been strongly fixed and reinforced to the structure of the instrument. In addition to this spectroradiometer, four broadband radiometers, covering the ultraviolet UVA and UVB bands, have been also installed on the plane. Thus, two UVA and two UVB sensors oriented upward and downward respectively are installed. Finally, two cameras, one upward and one downward, have been installed in order to provide information about sky condition along the fly. All the equipment has been especially reinforced to sustain the strong taking-off acceleration.
On this work, a detailed description of the experiment and preliminary results are presented
8ª Asamblea Hispano-Portuguesa de Geodesia y Geofísica, Evora (Portugal); 01/2014
[Show abstract][Hide abstract] ABSTRACT: In the framework of the spanish research project "Development and
validation of advanced atmospheric dispersion models for their
application in radiological emergency systems" (ref:CGL2008-00473) /CLI,
the "El Arenosillo" tower, belonging to the National Institute for
Aerospace Technology (INTA) was equiped with radon monitors and, since
2011, is providing reliable and high quality measurements of Rn-222 air
concentrations on an hourly basis at two elevations, namely 10 and 100 m
above ground level. This radionuclide data is accompanied by continuous
meteorological data including temperature, humidity, pressure and wind
speed / direction. The location of the station, at the very edge of the
Southern Europe, exposed to continental (rural, industrial and urban),
marine and Saharan air masses, together with the Rn-222 and
meteorological measurements, make it particularly attractive to study
the transport phenomena and the performance of meteorological and
transport models at all scales, as well as to carry out studies on the
vertical structure of the atmosphere in a coastal site. In this
context, two intensive measurement campaigns, including radio soundings,
were performed during October 2011 and May 2012, allowing the comparison
and a better understanding of the Rn-222 measurements under different
meteorological conditions. This work will present a first evaluation of
the two campaigns at the INTA station, analyzing the evolution of
Rn-222 concentration data and the results of the meteorological
numerical modelling of those episodes using the Weather Research and
Forecasting (WRF) model with different parameterizations. Finally, the
atmospheric dispersion model inter-comparison (HYSPLIT-WRF and
FLEXPART-WRF) with Rn-222 as a tracer is performed.
[Show abstract][Hide abstract] ABSTRACT: Air masses are characterized by physical (temperature, humidity) and chemical (transported gases and aerosols) properties, being associated their arrival to different meteorological scenarios. The knowledge of the air masses over a region is fundamental as complementary information in several atmospheric studies, being the calculation of back-trajectory the most widely used tool whenever air masses are analyzed. A study of air masses has been carried out in southwestern Iberian Peninsula using 5-day kinematic back trajectories computed by the HYSPLIT model at three heights (500, 1,500 and 3,000 m) from 1997 to 2007. The main aims have been to characterize their vertical behaviour and their thermal and humidity properties. Thirteen trajectory clusters have been defined, showing the northerly and westerly clusters a high coupling degree. Seasonal daily variation of potential temperature and specific humidity has been analyzed, obtaining higher differences among clusters in the cold season.
[Show abstract][Hide abstract] ABSTRACT: Forest and vegetation fires are a relevant atmospheric
source of both trace gases and aerosols (Crutzen and
Andreae, 1990; Andreae and Merlet, 2001). Biomass
burning has an important impact on the atmospheric
chemistry, air quality, climate and on global
biogeochemical cycles. Europe, and specially the
Mediterranean area, is a region that suffers, mostly in
warm seasons, the effects of wildfires. The aim of this
work has been to study the relation between the wildfires
occurred in summer 2006, which affected both Galicia
(Spanish northwest) and the north of Portugal and an
exceptional air pollution event observed in the southwest
of the Iberian Peninsula (IP) which produced the
increase of air pollutants to historical levels in some air
quality stations of this region (Adame et al., 2012).
The air pollution event was recorded by several
air quality stations located in this region, both inland and
coastal zones. These stations belong to the Air Quality
Network of the Environmental Council, Andalusia
Government. Three stations are suburban background
(San Fernando, Aljarafe and Santa Clara), two urban
backgrounds (El Carmen and Jerez) and one rural
background (El Arenosillo). Three are located close to
the coastal line (El Carmen, El Arenosillo and San
Fernando) and three inland (Jerez, Aljarafe and Santa
Clara). In the stations mentioned have been recorded
surface ozone, NO 2 , CO, particle number concentration
and PM10, but in all the stations not all the species are
measured. To know the trajectory performed by the air
masses that reach the event area, HYSPLIT model has
been used whereas the WRF-ARW model has been used
to achieve a detailed understanding of the mesoscale
The fires start on 2 August and were extinguished
on 16 August. Air pollution event occurred in the
southwest of the IP from 12 to 13 August. The air
pollution event in the southwest starts approximately at
17:00 UTC on 12 August when an unexpected increase
on surface ozone was observed in the two coastal
stations of El Arenosillo and El Carmen. From 18:00 to
21:00 UTC, the 200 µg m
as hourly values of surface
ozone in both monitoring sites are exceeded, with peaks
of 271 and 200 µg m
at 19:00 UTC at El Arenosillo and
El Carmen, respectively. At this time, particle number
concentration in the accumulation mode, which was
monitored at El Arenosillo, was 8380 cm
At El Carmen station a remarkable increase of
CO was also measured. From 17:00 UTC on 12 August
to 3:00 UTC on 13 August the 1500 µg m
exceeded continuously, with a peak of 1870 µg m
23:00 UTC. PM10 concentrations were also increased at
El Carmen from 18:00 UTC on 12 August with a peak of
243 µg m
at 23:00 UTC.
From 23:00 UTC on 12 August, surface ozone
starts to increase at San Fernando and Jerez stations,
remaining during the night with values up to 140 µg m
At 00:00 UTC on 13 August, peaks of 157 and 191 µg
are measured at Jerez and San Fernando respectively.
Regards to the CO, at San Fernando a peak of 1558 µg
was registered at 23:00 UTC on 12 August, while at
Jerez 167 µg m
were collected at 2:00 UTC on 13
From 00:00 to 13:00 UTC on 13 August the
PM10 in both monitoring sites remain at 100 µg m
with maximums of 184 µg m
at 00:00 and 162 µg m
at 08:00 UTC at San Fernando and Jerez respectively.
Thanks to the modelling tools, have been known that
after travelling approximately 1000 kilometres along the
Atlantic coast of Portugal, the fire plume went parallel to
the Gulf of Cadiz, affecting from the coast line to almost
40-50 km inland. However, the urban stations located in
the metropolitan area of Seville were not affected, since
air masses from the north didn’t reach this area.
[Show abstract][Hide abstract] ABSTRACT: On 12 and 13 August 2006, an exceptional air pollution event occurred in the southwest of the Iberian Peninsula (western Andalusia). High concentrations of surface ozone, CO and PM10 were registered at several air quality stations, in some cases reaching record values. During the late afternoon and evening of these two dates, the information and alert thresholds of surface ozone at coastal stations were exceeded, with peaks of 270 μg m−3. Concentrations of CO and PM10 reached 1800 μg m−3 and 240 μg m−3. Surface meteorological observations, back trajectories computed with the HYSPLIT model and wind and specific humidity fields from the meso-meteorological WRF-ARW model have all been used to gain an understanding of the origin of this event. The results indicate that this event was caused by the long-range transport of air masses from the wildfires that had occurred in the northwest of the Iberian Peninsula (Galicia and northern Portugal) during the first two weeks of August 2006. Air masses loaded with pollutants were transported approximately 1000 km from north to south, over Portugal and the Atlantic Ocean, to reach the southwestern Iberian Peninsula, with the consequent negative high impact on the air quality of this region.
[Show abstract][Hide abstract] ABSTRACT: There are several sites in which the relationship between the atmospheric dynamics and behaviour of pollutants is
difficult to understand, generally places with complex orography such as coastal areas or valleys. Inside the set of
atmospheric circulations, sea-land breezes are a phenomenon widely studied in many regions around the world
due to their interest in atmospheric dynamics and their impact on the local air pollution. Nowadays, to study with
sufficient accuracy different aspects related to its structure and dynamics, such as inland penetration of the sea
breeze front, the compensating return flow aloft or the features of the thermal internal boundary layer (TIBL)
formation, is needed a Weather Prediction System (WPS). There is a lack of these studies in South-western Iberian
Peninsula. Due to the orography characteristics, Guadalquivir valley, and emission levels, with industrial, urban
or biogenic origin, this region is suitable to present air pollution problems. Therefore, the accurate understanding
of the sea-land breeze characteristics will allow a reliable analysis of the air pollution. Thanks to observations,
in previous works have been identified two different sea-land breeze patterns in this area, called as pure and
non-pure. The aim is to increase the understanding of the meso-meteorological processes, analysing its structure,
behaviour and evolution along the Guadalquivir valley, applying the mesoscale meteorological model of high
resolution, Weather Research and Forecasting (WRF-ARW)
[Show abstract][Hide abstract] ABSTRACT: 222Rn concentration time series at 10 m and at 100 m have been measured hourly for one year at the meteorological station, El Arenosillo, on the Spanish southwest coast. A 222Rn flux characterization was also done.A seasonal analysis of atmospheric 222Rn concentration was performed and results for each season present evidence associated with the origin of air masses reaching the El Arenosillo station. An increase in 222Rn concentration was observed when the wind came from Morocco, the Sierra Morena and the Guadalquivir valley areas. On the other hand, a net 222Rn concentration decrease was found when the wind came from the Atlantic Ocean and the South of Portugal.Low 222Rn flux of 4 Bq m−2 h−1 was measured. This result makes this station a useful site for studies related to remote 222Rn source contributions because of low local 222Rn background. The measured annual average concentration of 222Rn gas at the El Arenosillo station is 3.51 ± 0.05 Bq m−3 at 10 m and 2.61 ± 0.05 Bq m−3 at 100 m.
[Show abstract][Hide abstract] ABSTRACT: The equatorial plasma bubbles (EPBs) have been studied using slant total electron content (sTEC) derived from GPS data. The sTEC has been calculated from data measured at 15 International GNSS Service (IGS) stations located from 90°W to 30°W, covering the ionospheric equatorial anomaly at the American sector, for the years 2000, 2001, 2004, 2005 and 2008. The Ionospheric Bubbles Seeker (IBS) application has been used to detect and characterize the sTEC depletions associated to the EPBs. This technique bases its analysis on the time-variation of the sTEC and the population variance of this time-variation. The default configuration has been used and an EPB has been considered when a sTEC depletion was greater than 5 TEC units (TECu). The hourly occurrence shows the well-known maximum number of depletions after the post-sunset. The monthly occurrence of the EPBs is also analyzed and compared with previous studies. The International Reference Ionosphere model (IRI) has been used to calculate the equatorial vertical drift (EVD) and the peak densities of the E- and F-layers (NmE and NmF2, respectively). The EVD variation has been compared with the seasonal variation of the EPB. A discussion between the yearly mean occurrence EPBs rate and the solar activity is included. The variation of the yearly mean depth and duration of the sTEC depletions with the solar activity conditions and its relation with the ionospheric characteristics given by the IRI model has been also studied.
Journal of Atmospheric and Solar-Terrestrial Physics 01/2012; 74. DOI:10.1016/j.jastp.2011.10.014 · 1.47 Impact Factor