Application of cluster analysis to surface ozone, NO₂ and SO₂ daily patterns in an industrial area in Central-Southern Spain measured with a DOAS system.

The daily variations of surface ozone, NO₂ and SO₂ have been investigated in a heavily industrialised area in the centre of the Iberian Peninsula (Puertollano) using hourly values recorded during two years (2008-2009) with an active LP-DOAS system. The meteorological conditions and air masses have been studied using the HYSPLIT model. The maximum hourly levels of these air pollutants exceeded 100 ppb for ozone, 150 ppb for SO₂ and 210 ppb for NO₂. However, mean values for ozone, NO₂ and SO₂ were of 49, 10 and 3 ppb respectively. Daily-monthly evolutions (defined as daily evolutions for different months) have been analysed in order to know the general daily behaviour of these species. Air pollution problems have been identified using the thresholds defined in the European Directive 2008. The limits to protect human health (human health protection limitations) have been exceeded during the study period. In order to find a set of representative daily cycles for each pollutant at different air quality regimes, a K-mean cluster technique has been applied. Five and four optimal cluster numbers have been obtained for the daily patterns of ozone and SO₂ respectively. In addition, we studied the daily variation of the temperature, relative and specific humidity and wind speed associated with each air pollutant daily pattern. Ozone daily patterns showed typical daily variations with one exception of a cluster which presents a peak in the early morning. For SO₂, the first two clusters present a low mixing ratio, however cluster 3 and 4 are less frequent but with higher levels. The more frequent air pollutant daily patterns do not exceed the threshold defined in the Directive. Nevertheless, clusters with lower frequency (representing between 5 and 7% of days) exceed the thresholds and could be considered as air pollution events.

[1]  F. Borchi,et al.  Impact of vertical transport processes on the tropospheric ozone layering above Europe. Part I: Study of air mass origin using multivariate analysis, clustering and trajectories , 2005 .

[2]  M. Khoder,et al.  Atmospheric concentrations of polycyclic aromatic hydrocarbons and selected nitrated derivatives in Greater Cairo, Egypt , 2011 .

[3]  Ahmet Palazoglu,et al.  A cluster aggregation scheme for ozone episode selection in the San Francisco, CA Bay Area , 2006 .

[4]  J. Carretero,et al.  Assessment of ozone variations and meteorological effects in an urban area in the Mediterranean Coast. , 2002, The Science of the total environment.

[5]  A. van Donkelaar,et al.  Sources, distribution, and acidity of sulfate–ammonium aerosol in the Arctic in winter–spring , 2011 .

[6]  J. Plane,et al.  UV‐Visible Differential Optical Absorption Spectroscopy (DOAS) , 2007 .

[7]  M. Schulz,et al.  The global distribution of acidifying wet deposition. , 2002, Environmental Science and Technology.

[8]  J. Adame,et al.  Analysis of NO, NO2, NOx, O3 and oxidant (OX = O3 + NO2) levels measured in a metropolitan area in the southwest of Iberian Peninsula , 2012 .

[9]  P. Leighton,et al.  Photochemistry of Air Pollution , 1961 .

[10]  J. Adame,et al.  Surface ozone comparison conducted in two rural areas in central-southern Spain , 2011, Environmental Science and Pollution Research.

[11]  Ulrich Platt,et al.  Differential optical absorption spectroscopy , 2008 .

[12]  J. Baker,et al.  A cluster analysis of long range air transport pathways and associated pollutant concentrations within the UK , 2010 .

[13]  A. Stohl,et al.  On the pathways and timescales of intercontinental air pollution transport , 2002 .

[14]  M. McCormick,et al.  Development of global aerosol models using cluster analysis of Aerosol Robotic Network (AERONET) measurements , 2005 .

[15]  G. B. Avery,et al.  Rainwater monocarboxylic and dicarboxylic acid concentrations in southeastern North Carolina, USA, as a function of air-mass back-trajectory , 2006 .

[16]  N. Mihalopoulos,et al.  An investigation of the meteorological and photochemical factors influencing the background rural and marine surface ozone levels in the Central and Eastern Mediterranean , 2008 .

[17]  Pinhua Xie,et al.  Intercomparison of NOx, SO2, O3, and aromatic hydrocarbons measured by a commercial DOAS system and traditional point monitoring techniques , 2004 .

[18]  J. Adame,et al.  Year-Round Observations of NO, NO2, O3, SO2, and Toluene Measured with a DOAS System in the Industrial Area of Puertollano, Spain , 2009 .

[19]  David D. Parrish,et al.  Air quality progress in North American megacities: A review , 2011 .

[20]  Brian Everitt,et al.  Cluster analysis , 1974 .

[21]  G. Mcfiggans,et al.  Seasonal Variation of NOx Loss Processes Coupled to the HNO3 Formation in a Daytime Urban Atmosphere: A Model Study , 2007 .

[22]  K. Sartelet,et al.  Modeling of photolysis rates over Europe: impact on chemical gaseous species and aerosols , 2010 .

[23]  X. Querol,et al.  Controlling influences on daily fluctuations of inhalable particles and gas concentrations: Local versus regional and exotic atmospheric pollutants at Puertollano, Spain , 2006 .

[24]  D. Deligiorgi,et al.  On the limits of the air pollution predictability: the case of the surface ozone at Athens, Greece , 2011, Environmental Science and Pollution Research.

[25]  J. Lelieveld,et al.  Global Air Pollution Crossroads over the Mediterranean , 2002, Science.

[26]  M. Jenkin.  Analysis of sources and partitioning of oxidant in the UK—Part 2: contributions of nitrogen dioxide emissions and background ozone at a kerbside location in London , 2004 .

[27]  H. Elminir.  Dependence of urban air pollutants on meteorology. , 2005, The Science of the total environment.

[28]  Ulrich Platt,et al.  Differential optical absorption spectroscopy (DOAS) , 1994 .

[29]  U. Platt,et al.  Differential Absorption Spectroscopy , 2008 .

[30]  Romà Tauler,et al.  Investigation of geographical and temporal distribution of tropospheric ozone in Catalonia (North-East Spain) during the period 2000–2004 using multivariate data analysis methods , 2006 .

[31]  John S. Holloway,et al.  Export of North American Ozone Pollution to the North Atlantic Ocean , 1993, Science.

[32]  J. Seinfeld,et al.  Atmospheric Chemistry and Physics: From Air Pollution to Climate Change , 1997 .

[33]  J M Baldasano,et al.  Air quality data from large cities. , 2003, The Science of the total environment.

[34]  James N. Pitts,et al.  Chemistry of the Upper and Lower Atmosphere: Theory, Experiments, and Applications , 1999 .

[35]  R. J. Yamartino,et al.  A new air quality regime classification scheme for O3, NO2, SO2 and PM10 observations sites , 2005 .

[36]  Mihalis Vrekoussis,et al.  Photochemical ozone production in the Eastern Mediterranean , 2006 .

[37]  R. Steinbrecher,et al.  Detection of pollution transport events southeast of Mexico City using ground-based visible spectroscopy measurements of nitrogen dioxide , 2009 .

[38]  Performance of a differential optical absorption spectrometer for surface O3 measurements in the finnish arctic , 1997 .

[39]  Comparison of an open path differential optical absorption spectroscopy system and a conventional in situ monitoring system on the basis of long-term measurements of SO2, NO2, and O3 , 2001 .

[40]  H. Ueda,et al.  MICS-Asia II: Impact of global emissions on regional air quality in Asia , 2008 .

[41]  Pasquale Avino,et al.  Ten-year measurements of gaseous pollutants in urban air by an open-path analyzer , 2008 .

[42]  Oksana A. Tarasova,et al.  A climatology of surface ozone in the extra tropics: cluster analysis of observations and model results , 2007 .

[43]  R. Draxler.  An Overview of the HYSPLIT_4 Modelling System for Trajectories, Dispersion, and Deposition , 1998 .

[44]  Mark Lawrence,et al.  Evaluation of emissions and air quality in megacities , 2008 .