L. Alonso

University of the Basque Country

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Gotzon Gangoiti

University of the Basque Country

García Fernández

University of the Basque Country

M. Navazo

University of the Basque Country

J. Iza

Universidad San Francisco de Quito

M.C. Gómez

University of the Basque Country

E. Sáez De Cámara

University of the Basque Country

Nieves Durana

University of the Basque Country

V. Valdenebro

University of the Basque Country

E. García

University of the Basque Country

J. L. Ilardia

University of the Basque Country

Cooperative Institutions

University of the Basque Country

Institute of Environmental Assessment and Water Research

Consejo Superior de Investigaciones Científicas

Fundación General

Mediterranean Center for Environmental Studies

Universitat de Barcelona

Ente Vasco de la Energía

Universidad Complutense de Madrid

Centre National de la Recherche Scientifique

Centro de Investigaciones Energéticas, Medioambientales y Tecnológicas

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Phenomenology of summer ozone episodes over the Madrid Metropolitan Area, central Spain

Xavier Querol Andrés Alástuey Gotzon Gangoiti Noemí Pérez Hong K. Lee

Abstract. Various studies have reported that photochemical nucleation of new ultrafine particles (UFP) in urban environments within high insolation regions occurs simultaneously with high ozone (O3). In this work, we evaluate the atmospheric dynamics leading to summer O3 episodes in the Madrid Air Basin (Central Iberia) by means of measuring a 3D distribution of concentrations for both pollutants. To this end, we obtained vertical profiles (up to 1200 m, above ground level) using tethered balloons and miniaturised instrumentation at a suburban site located to the SW of the Madrid Metropolitan Area (MMA), Majadahonda site (MJDH) in July 2016. Simultaneously, measurements of an extensive number of air quality and meteorological parameters were carried out at 3 supersites across the MMA. Furthermore, data from O3-soundings and daily radio-sounding were also used to interpret the atmospheric dynamics. The results demonstrate the concatenation of venting and accumulation episodes, with relative O3 lows (venting) and peaks (accumulation) in surface levels. Regardless of the episode type, fumigation of high altitude O3-rich layers contributes the major proportion of surface O3 concentrations. Accumulation episodes are characterised by a relatively thinner planetary boundary layer (PBL 2400 m). This orographic-meteorological setting causes the vertical recirculation of air masses and the enrichment of O3 in the lower tropospheric layers. When the highly polluted urban plume from Madrid is affected by these dynamics, the highest Ox (O3 + NO2) concentrations are recorded in the MMA. Vertical O3 profiles during venting episodes, with marked synoptic winds and a deepening of the PBL reaching > 2000 m above sea level, were characterised by an upward gradient in O3 levels, whereas low-altitude O3 concentration maxima due to local/regional production were found during the accumulation episodes. The two contributions to O3 surface levels (fumigation from high altitude strata and local/regional production) require very different approaches for policy actions. In contrast to O3 vertical top-down transfer, UFP are formed in the lowest levels and are transferred upwards progressively with the growth of the PBL.

Orographic lift

Ground level

Tropopause

10.5194/acp-2017-1014

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Citations (7)

Evaluation of Uncertainty Associated with Determination of Particle-bound PAHs in Ambient Area by TD-GC/MS and Soxhlet-GC/MS

Aerosol and Air Quality Research (2018)

Iñaki Elorduy Nieves Durana García Fernández M.C. Gómez L. Alonso

Knowing the uncertainty associated with an analytical method is necessary to evaluating the quality of the results. In this work, the uncertainty associated with the analytical measurement of polycyclic aromatic compounds (PAHs) in ambient air using thermal desorption coupled with gas chromatography-mass spectrometry (TD-GC/MS) was evaluated. The study focused on analyses of the particulate phase (PM10), and the results were compared to those obtained with a conventional solvent extraction (Soxhlet-GC/MS). The main sources of the combined uncertainty were the calibration curve, recovery of the extraction stage, area or volume of the sample and volume of air. TD-GC/MS reported a lower combined uncertainty (< 10%) than Soxhlet-GC/MS (values between 11% and 18%) for the measurement of particle-bound PAHs in the air, which was primarily contributed by the recovery of the analyzed PAHs and the calibration curves.

Thermal desorption

Accelerated solvent extraction

10.4209/aaqr.2017.12.0578

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Daily precipitation in Northern Iberia: Understanding the recent changes after the circulation variability in the North Atlantic sector

Journal of Geophysical Research Atmospheres (2015)

E. Sáez De Cámara Gotzon Gangoiti L. Alonso J. Iza

Abstract Trends in the characteristics of daily precipitation over Northern Iberia (NIB) are analyzed after 14 daily records covering the last 40 years plus seven century‐length time series. Results reveal an evolution to drier conditions with subregional variations: in western and central subregions, the decrease in both the occurrence and the intensity of wet days results in a statistically significant decline of total precipitation. Contrary to other regions in the Iberian Peninsula, the lack of correlation between the North Atlantic Oscillation (NAO) index and the observed rainfall anomalies within NIB suggests that the dominance of a positive NAO mode from the late 1970s to 2002 cannot explain the trends. The land‐sea and mountain distribution creates sharp rainfall transitions depending on the pathways of the moisture‐laden winds. Consequently, NIB and other mountainous regions in the margins of the European continental water divide are sensitive to small changes in the NAO pressure centers and can exhibit both positive and negative rainfall anomalies for each NAO mode. A novel methodology for identifying changes in the NAO modes, consistent with the observed pressure/precipitation anomalies at both continental and regional scales, is presented. After the disaggregation of each dominant NAO wet season into two categories, the main rainfall changes in the NIB region can be explained in the context of the NAO variability during the last decades. The reported (sub)regional rainfall differences stress the need of caution when using NAO reconstructions, based in site specific rainfall anomalies, for the interpretation of the past climate precipitation variability in areas of complex terrain.

Dominance (genetics)

Peninsula

Atmospheric Circulation

10.1002/2015jd023306

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Citations (14)

Origin of the water vapor responsible for the European extreme rainfalls of August 2002: 2. A new methodology to evaluate evaporative moisture sources, applied to the August 11-13 central European rainfall episode

Journal of Geophysical Research Atmospheres (2011)

Gotzon Gangoiti Igor Gómez E. Sáez De Cámara L. Alonso M. Navazo

[1] An innovative technique has been developed to assess moisture sources contributing to precipitation. It represents an advance with respect to previously developed methodologies because it allows to discriminate more effectively between terrestrial versus oceanic sources, and also to detect with greater precision the relative importance of remote versus local sources together with the sequence of evaporation associated with a rainfall event. It is based upon the use of a mesoscale model to simulate a selected precipitation episode and a Lagrangian trajectory model to evaluate three-dimensional back-trajectories in order to track the vapor parcels transporting the target precipitation to their surface evaporative sources. An extreme sequence of rainfall events occurred over central Europe between August 11th and 13th is chosen to put the methodology into test. A domain centered in the region and spanning 6372 km in the W–E direction and 5940 km in the N–S direction is chosen to assess moisture sources. Results show the evolving role of various sources throughout the duration of the event, indicating that they shift from the southern to northern and eastern source regions, while a simultaneous decrease of marine sources with respect to terrestrial sources occurs from the onset of the event to its ending phase. The capability of discriminating moisture sources with precision is an important requirement to better understand the mechanisms of extreme rainfalls.

10.1029/2010jd015538

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Citations (24)

Application Of Cluster Analysis InOptimization Processes Of SurfaceMeteorological And Air Quality Networks

WIT Transactions on Ecology and the Environment (1970)

Gabriel Ibarra‐Berastegi L. Alonso M. Navazo Gotzon Gangoiti

10.2495/air940571

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Volatile organic compounds in urban and industrial atmospheres: measurement techniques and data analysis

International Journal of Environmental & Analytical Chemistry (2003)

M. Navazo Nieves Durana L. Alonso García Fernández J. L. Ilardia

Main results of 62 volatile organic compounds (VOCs) 'continuous' on-line measurement obtained at the Air Quality Monitoring Station sited at the School of Engineering of Bilbao (Northern Spain) are presented. The system has been put into operation between 1997 and 2001 in an area influenced by urban and industrial emissions. Initially, the measurement method and data validation process are described and, then, the application of combined statistical analysis techniques for inferring the mixed organic compound sources impacting the receptor location. The addition of a simple meteorological study for the characterisation of the prevailing winds combined with pollution roses has confirmed this statistical results and allows, for each compound, the discrimination of its urban - mainly trafic - or industrial origin.

Volatile organic compound

Statistical Analysis

Industrial city

Industrial area

10.1080/0306731021000050705

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Citations (24)

Cartagena: diseño y optimización de una red de vigilancia e integración de emisiones industriales, para aplicación al diagnóstico y control de calidad del aire

A. Albizuri Churruca Marino Navazo Muñoz Cristina Gutiérrez-Cañas Mateo L. Alonso J. Hierro Santacoloma

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North African soil dust and European pollution transport to America during the warm season: Hidden links shown by a passive tracer simulation

Journal of Geophysical Research Atmospheres (2006)

Gotzon Gangoiti L. Alonso M. Navazo García Fernández Millan M. Millán

A mesoscale atmospheric model coupled with a dispersion model is used to establish source‐receptor relationships between the European‐North African aerosol episodes observed over the Caribbean every year during summer and their main sources. The simulation period extends from 15 July to 16 August 1991, concurrent with the flight campaign of the European Project RECAPMA (Millán et al., 1997; Gangoiti et al., 2001). We now extend the simulations to reach the tropical Atlantic and the Caribbean, and we make use of the TOMS aerosol index data (Nimbus 7 satellite) to substantiate the simulations at the regional‐to‐continental scale. Our simulations, based on passive tracer release from selected source regions, show that emissions from southern Europe can either take a full‐Atlantic shortcut to the American coasts or enter the Mediterranean basin eastward to turn back to America following a longer pathway: The emissions cross the southern Mediterranean coast to northern Africa, and then they are vented to the middle troposphere (2000–6000 m MSL), mixed within the Saharan air layer (SAL) and transported westward to the tropical Atlantic (TA) and America. Recirculations around the Atlas Mountains and perturbed conditions over the area modulate the export of the European tracer (and soil dust) into America. We found transit times of 11–12 days for the full Atlantic shortcut and 20–26 days for the longer pathway across northern Africa. Under the simulated conditions, southern Europe can contribute with more than the 50% of its emissions to America, while northern Europe shows longer transit times and less transport efficiency.

Tropical Atlantic

TRACER

10.1029/2005jd005941

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Citations (43)

Optimization and Validation of Thermal Desorption Gas Chromatography-Mass Spectrometry for the Determination of Polycyclic Aromatic Hydrocarbons in Ambient Air

Journal of Analytical Methods in Chemistry (2018)

Iñaki Elorduy Nieves Durana García Fernández M.C. Gómez L. Alonso

Thermal desorption (TD) coupled with gas chromatography/mass spectrometry (TD-GC/MS) is a simple alternative that overcomes the main drawbacks of the solvent extraction-based method: long extraction times, high sample manipulation, and large amounts of solvent waste. This work describes the optimization of TD-GC/MS for the measurement of airborne polycyclic aromatic hydrocarbons (PAHs) in particulate phase. The performance of the method was tested by Standard Reference Material (SRM) 1649b urban dust and compared with the conventional method (Soxhlet extraction-GC/MS), showing a better recovery (mean of 97%), precision (mean of 12%), and accuracy (±25%) for the determination of 14 EPA PAHs. Furthermore, other 15 nonpriority PAHs were identified and quantified using their relative response factors (RRFs). Finally, the proposed method was successfully applied for the quantification of PAHs in real 8 h-samples (PM10), demonstrating its capability for determination of these compounds in short-term monitoring.

Thermal desorption

Accelerated solvent extraction

Sample Preparation

10.1155/2018/8734013

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Citations (16)

Aplication of Positive Matrix Factorization and K-means clustering to source apportionment of ambient air VOCs in a urban area with high industrial influence.

EGU General Assembly Conference Abstracts (2009)

A. Albizuri Nieves Durana M.C. Gómez M. Navazo L. Alonso

Apportionment

Matrix (chemical analysis)

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