Aerosol properties over two urban sites in South Spain during an extended stagnation episode in winter season

Lyamani, H.; Fernández‐Gálvez, J.; Pérez-Ramírez, D.; Valenzuela, Abel; Antón, Manuel; Alados, I.; Titos, Gloria; Olmo, F.J.; Alados-Arboledas, L.

doi:10.1016/j.atmosenv.2012.08.050

Cited by 51 publications

(24 citation statements)

References 32 publications

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“…20-21 and 25-27 July) possess relatively low values of AODs (∼ 0.15) and V (∼ 0.10 µm 3 µ −2 ), and medium values of α(440-870) (∼ 1.0). The Iberian Peninsula and the study area are important sources of anthropogenic pollution (Lyamani et al, 2010(Lyamani et al, , 2012, but during the summer season a significant amount of coarse particles from the ground are also injected into the atmosphere (Alados- Pérez-Ramírez et al, 2012a). This effect explains the relatively large values of r eff (0.30-0.55 µm) compared to those obtained in polluted areas (Dubovik et al, 2002b).…”

Section: Day-to-night Time Evolution Of Columnar Microphysical Propermentioning

confidence: 86%

High temporal resolution estimates of columnar aerosol microphysical parameters from spectrum of aerosol optical depth by linear estimation: application to long-term AERONET and star-photometry measurements

Pérez-Ramírez

Veselovskii²,

Whiteman

et al. 2015

Atmos. Meas. Tech.

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Abstract. This work deals with the applicability of the linear estimation technique (LE) to invert spectral measurements of aerosol optical depth (AOD) provided by AERONET CIMEL sun photometers. The inversion of particle properties using only direct-sun AODs allows the evaluation of parameters such as effective radius (r eff ) and columnar volume aerosol content (V ) with significantly better temporal resolution than the operational AERONET algorithm which requires both direct sun and sky radiance measurements. Sensitivity studies performed demonstrate that the constraints on the range of the inversion are very important to minimize the uncertainties, and therefore estimates of r eff can be obtained with uncertainties less than 30 % and of V with uncertainties below 40 %. The LE technique is applied to data acquired at five AERONET sites influenced by different aerosol types and the retrievals are compared with the results of the operational AERONET code. Good agreement between the two techniques is obtained when the fine mode predominates, while for coarse mode cases the LE results systematically underestimate both r eff and V . The highest differences are found for cases where no mode predominates. To minimize these biases, correction functions are developed using the multi-year database of observations at selected sites, where the AERONET retrieval is used as the reference. The derived corrections are tested using data from 18 other AERONET stations offering a range of aerosol types. After correction, the LE retrievals provide better agreement with AERONET for all the sites considered. Finally, the LE approach developed here is applied to AERONET and star-photometry measurements in the city of Granada (Spain) to obtain dayto-night time evolution of columnar aerosol microphysical properties.

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Section: Day-to-night Time Evolution Of Columnar Microphysical Propermentioning

confidence: 86%

High temporal resolution estimates of columnar aerosol microphysical parameters from spectrum of aerosol optical depth by linear estimation: application to long-term AERONET and star-photometry measurements

Pérez-Ramírez

Veselovskii²,

Whiteman

et al. 2015

Atmos. Meas. Tech.

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“…In winter and part of spring, the Azores anticyclone presents its lowest intensity and usually stays west of the western Mediterranean Basin (Millán et al, 1997). Weak gradient anticyclonic conditions are recurrent over the western Mediterranean Basin and favor the stagnation of pollu-tants near populated and industrialized areas around the basin (Lyamani et al, 2012). The thermal inversions associated with such anticyclonic conditions and the local breezes that may be activated by solar radiation help the pollutants to disperse over the basin.…”

Section: Methodsmentioning

confidence: 99%

Aerosol optical, microphysical and radiative properties at regional background insular sites in the western Mediterranean

et al. 2016

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Abstract. In the framework of the ChArMEx (the Chemistry-Aerosol Mediterranean Experiment; http://charmex.lsce.ipsl.fr/) program, the seasonal variability of the aerosol optical, microphysical and radiative properties derived from AERONET (Aerosol Robotic Network; http://aeronet.gsfc.nasa.gov/) is examined in two regional background insular sites in the western Mediterranean Basin: Ersa (Corsica Island, France) and Palma de Mallorca (Mallorca Island, Spain). A third site, Alborán (Alborán Island, Spain), with only a few months of data is considered for examining possible northeast-southwest (NE-SW) gradients of the aforementioned aerosol properties. The AERONET dataset is exclusively composed of level 2.0 inversion products available during the 5-year period 2011-2015. AERONET solar radiative fluxes are compared with groundand satellite-based flux measurements. To the best of our knowledge this is the first time that AERONET fluxes are compared with measurements at the top of the atmosphere. Strong events (with an aerosol optical depth at 440 nm greater than 0.4) of long-range transport aerosols, one of the main drivers of the observed annual cycles and NE-SW gradients, are (1) mineral dust outbreaks predominant in spring and summer in the north and in summer in the south and (2) European pollution episodes predominant in autumn. A NE-SW gradient exists in the western Mediterranean Basin for the aerosol optical depth and especially its coarse-mode fraction, which all together produces a similar gradient for the aerosol direct radiative forcing. The aerosol fine mode is rather homogeneously distributed. Absorption properties are quite variable because of the many and different sources of anthropogenic particles in and around the western Mediterranean Basin: North African and European urban areas, the Iberian and Italian peninsulas, most forest fires and ship emissions. As a result, the aerosol direct forcing efficiency, more dependent to absorption than the absolute forcing, has no marked gradient.

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“…This, in combination with pollutant emissions can lead to a large accumulation of particles near the surface (e.g. Lyamani et al, 2012). There are no large industries in the surroundings and the main aerosol local source is road traffic (Titos et al, 2014).…”

Section: Context For the Studymentioning

confidence: 99%

“…Meteorological conditions and emissions are competitive processes determining the magnitude of pollutant concentrations in the atmosphere (e.g. Lyamani et al, 2012). Therefore, the main meteorological variables (temperature, relative humidity, wind speed and direction and precipitation) have been compared for both periods in order to ensure that changes in air pollutant concentrations are caused by changes in emissions rather than changes in the meteorological conditions.…”

Section: Studymentioning

confidence: 99%

Evaluation of the impact of transportation changes on air quality

Titos

Lyamani

Drinovec

et al. 2015

Atmospheric Environment

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h i g h l i g h t sEffect of air quality plans on black carbon concentrations has been evaluated. Black carbon concentrations were reduced by limiting traffic to public transport. Reorganization of bus routes and renewal of the bus fleet improve air quality. a b s t r a c t Transport regulation at local level for the abatement of air pollution has gained significant traction in the EU. In this work, we analyze the effect of different transportation changes on air quality in two similarly sized cities: Granada (Spain) and Ljubljana (Slovenia). Several air pollutants were measured at both sites before and after the implementation of the changes. In Ljubljana, a 72% reduction of local black carbon (BC), from 5.6 to 1.6 mg/m 3 , was observed after the restriction was implemented. In Granada, statistically significant reductions of 1.3 mg/m 3 (37%) in BC and of 15 mg/m 3 (33%) in PM 10 concentrations were observed after the public transportation re-organization. However, the improvement observed in air quality was very local since other areas of the cities did not improve significantly. We show that closing streets to private traffic, renewal of the bus fleet and re-organization of the public transportation significantly benefit air quality.

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Aerosol properties over two urban sites in South Spain during an extended stagnation episode in winter season

Cited by 51 publications

References 32 publications

High temporal resolution estimates of columnar aerosol microphysical parameters from spectrum of aerosol optical depth by linear estimation: application to long-term AERONET and star-photometry measurements

High temporal resolution estimates of columnar aerosol microphysical parameters from spectrum of aerosol optical depth by linear estimation: application to long-term AERONET and star-photometry measurements

Aerosol optical, microphysical and radiative properties at regional background insular sites in the western Mediterranean

Evaluation of the impact of transportation changes on air quality

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