title: Ambient air levels of volatile organic compounds (VOC) and nitrogen dioxide (NO2) in a medium size city in Northern Spain.
abstract: Ambient concentrations of volatile organic compounds (VOC) and nitrogen dioxide (NO2) were measured by means of passive sampling at 40 sampling points in a medium-size city in Northern Spain, from June 2006 to June 2007. VOC and NO2 samplers were analysed by thermal desorption followed by gas chromatography/mass-selective detector and by visible spectrophotometry, respectively. Mean concentrations of benzene, toluene, ethylbenzene, xylenes, propylbenzene, trimethylbenzenes, and NO(2) were 2.84, 13.26, 2.15, 6.01, 0.59, 1.32 and 23.17 microg m(-3) respectively, and found to be highly correlated. Their spatial distribution showed high differences in small distances and pointed to traffic as the main emission source of these compounds. The lowest levels of VOC and NO2 occurred during summer, owing to the increase in solar radiation and to lower traffic densities. Mean concentrations of benzene and NO2 exceeded the European limits at some of the monitored points.
authors.affiliation: Laboratorio Integrado de Calidad Ambiental (LICA), Departamento de Química y Edafología, Facultad de Ciencias, Universidad de Navarra. Irunlarrea 1, 31008, Pamplona, Navarra, Spain. mparravi@alumni.unav.es
authors.forename: M A
authors.initials: MA
authors.lastname: Parra
authors.forename: D
authors.initials: D
authors.lastname: Elustondo
authors.forename: R
authors.initials: R
authors.lastname: Bermejo
authors.forename: J M
authors.initials: JM
authors.lastname: Santamaría
mesh_terms: D000388:Air / Q000032:analysis*; D000397:Air Pollution / Q000032:analysis; D001554:Benzene / Q000032:analysis; D001555:Benzene Derivatives / Q000032:analysis; D002940:Circadian Rhythm; D008401:Gas Chromatography-Mass Spectrometry; D006801:Humans; D009585:Nitrogen Dioxide / Q000032:analysis*; D012621:Seasons; D013030:Spain; D014050:Toluene / Q000032:analysis; D014505:Urban Population; D001335:Vehicle Emissions / Q000032:analysis; D055549:Volatile Organic Compounds / Q000032:analysis*; D014992:Xylenes / Q000032:analysis
chemical_list: D001555:Benzene Derivatives; D001335:Vehicle Emissions; D055549:Volatile Organic Compounds; D014992:Xylenes; D014050:Toluene; D001554:Benzene; D009585:Nitrogen Dioxide