title: Spatial and temporal variations and mobile source emissions of polycyclic aromatic hydrocarbons in Quito, Ecuador.
abstract: Motor vehicles are a major source of air pollution in Quito, Ecuador; however, little work has been done to characterize spatial and temporal variations in traffic-related pollutants, or to measure pollutants in vehicle emissions. We measured PAH continuously for one year at two residential sites in Quito, and PAH and traffic patterns for one week near a busy roadway. Morning rush-hour traffic and temperature inversions caused daily PAH maxima between 06:00 and 08:00. SO2, NOx, CO, and PM(2.5) behaved similarly. At the residential sites PAH levels during inversions were 2-3-fold higher than during the afternoon, and 10-16-fold higher than 02:00-03:00 when levels were lowest. In contrast, at the near-roadway site, PAH concentrations were 3-6-fold higher than at the residential sites, and the effects of inversions were less pronounced. Cars and buses accounted for >95% of PAH at the near-roadway site. Near-roadway PAH concentrations were comparable to other polluted cities.
authors.affiliation: Department of Civil and Environmental Engineering, Tufts University, Medford, MA, USA.
authors.forename: Megan V
authors.initials: MV
authors.lastname: Brachtl
authors.forename: John L
authors.initials: JL
authors.lastname: Durant
authors.forename: Carlos Paez
authors.initials: CP
authors.lastname: Perez
authors.forename: Jorge
authors.initials: J
authors.lastname: Oviedo
authors.forename: Fernando
authors.initials: F
authors.lastname: Sempertegui
authors.forename: Elena N
authors.initials: EN
authors.lastname: Naumova
authors.forename: Jeffrey K
authors.initials: JK
authors.lastname: Griffiths
mesh_terms: D000393:Air Pollutants / Q000032:analysis*; D004484:Ecuador; D004784:Environmental Monitoring / Q000295:instrumentation / Q000379:methods; D010507:Periodicity; D011084:Polycyclic Aromatic Hydrocarbons / Q000032:analysis*; D012621:Seasons; D014504:Urban Health / Q000706:statistics & numerical data*; D001335:Vehicle Emissions / Q000032:analysis*; D014887:Weather
chemical_list: D000393:Air Pollutants; D011084:Polycyclic Aromatic Hydrocarbons; D001335:Vehicle Emissions