title: Butenes and butadiene in urban air.
abstract: Samples of urban air hydrocarbons were taken on specifically made adsorbent cartridges and analysed by gas chromatography after thermal desorption. The four isomeric butenes and 1,3-butadiene were favourably resolved and separated from the abundant alkanes on an aluminium oxide PLOT column. The concentrations of butadiene, reflecting outdoor urban exposure, were in the range of 0.5-5 micrograms/m3. An approximate 1:4 ratio was observed between butadiene and propene which both originate predominantly from vehicle exhaust. The four butenes made up approximately 50% of the propene concentration in exhaust-polluted air, with methylpropene greater than 1-butene greater than trans-2-butene greater than cis-2-butene. Petrol vapour contributed less than exhaust but about five times more to the 2-butenes than to methylpropene and 1-butene. The highest exposure levels of butadiene and butenes were consistently observed in the vicinity of exhaust pipes and petrol-fuelled vehicles.
authors.affiliation: Department of Chemical Environmental Science, Chalmers University of Technology, Göteborg, Sweden.
authors.forename: L
authors.initials: L
authors.lastname: Löfgren
authors.forename: G
authors.initials: G
authors.lastname: Petersson
mesh_terms: D000393:Air Pollutants / Q000032:analysis*; D002070:Butadienes / Q000032:analysis*; D002073:Butanes / Q000032:analysis*; D002849:Chromatography, Gas / Q000379:methods; D004781:Environmental Exposure; D006801:Humans; D007536:Isomerism; D013548:Sweden; D014504:Urban Health; D001335:Vehicle Emissions
chemical_list: D000393:Air Pollutants; D002070:Butadienes; D002073:Butanes; D001335:Vehicle Emissions