title: Assessment of indoor and outdoor PM species at schools and residences in a high-altitude Ecuadorian urban center.
abstract: An air monitoring campaign to assess children's environmental exposures in schools and residences, both indoors and outdoors, was conducted in 2010 in three low-income neighborhoods in Z1 (north), Z2 (central), and Z3 (southeast) zones of Quito, Ecuador - a major urban center of 2.2 million inhabitants situated 2850 m above sea level in a narrow mountainous basin. Z1 zone, located in northern Quito, historically experienced emissions from quarries and moderate traffic. Z2 zone was influenced by heavy traffic in contrast to Z3 zone which experienced low traffic densities. Weekly averages of PM samples were collected at schools (one in each zone) and residences (Z1 = 47, Z2 = 45, and Z3 = 41) every month, over a twelve-month period at the three zones. Indoor PM2.5 concentrations ranged from 10.6 ± 4.9 μg/m(3) (Z1 school) to 29.0 ± 30.5 μg/m(3) (Z1 residences) and outdoor PM2.5 concentrations varied from 10.9 ± 3.2 μg/m(3) (Z1 school) to 14.3 ± 10.1 μg/m(3) (Z2 residences), across the three zones. The lowest values for PM10-2.5 for indoor and outdoor microenvironments were recorded at Z2 school, 5.7 ± 2.8 μg/m(3) and 7.9 ± 2.2 μg/m(3), respectively. Outdoor school PM concentrations exhibited stronger associations with corresponding indoor values making them robust proxies for indoor exposures in naturally ventilated Quito public schools. Correlation analysis between the school and residential PM size fractions and the various pollutant and meteorological parameters from central ambient monitoring (CAM) sites suggested varying degrees of temporal relationship. Strong positive correlation was observed for outdoor PM2.5 at Z2 school and its corresponding CAM site (r = 0.77) suggesting common traffic related emissions. Spatial heterogeneity in PM2.5 concentrations between CAM network and sampled sites was assessed using Coefficient of Divergence (COD) analysis. COD values were lower when CAM sites were paired with outdoor measurements (<0.2) and higher when CAM and indoor values were compared (>0.2), suggesting that CAM network in Quito may not represent actual indoor exposures.
authors.affiliation: Department of Public Health Sciences, The University of Texas at El Paso, El Paso, TX, 79968, USA.
authors.forename: Amit U
authors.initials: AU
authors.lastname: Raysoni
authors.affiliation: Department of Environmental Health, School of Public Health, Indiana University, Bloomington, IN 47405, USA; Proyecto Prometeo, Secretaria de Education Superior, Ciencia y Tecnologia (SENESCYT), Quito, Ecuador; Centro de Biomedicina, Universidad Central del Ecuador, Quito, Ecuador. Electronic address: rarmijos@iu.edu.
authors.forename: Rodrigo X
authors.initials: RX
authors.lastname: Armijos
authors.affiliation: Department of Environmental Health, School of Public Health, Indiana University, Bloomington, IN 47405, USA; Proyecto Prometeo, Secretaria de Education Superior, Ciencia y Tecnologia (SENESCYT), Quito, Ecuador; Centro de Biomedicina, Universidad Central del Ecuador, Quito, Ecuador.
authors.forename: M Margaret
authors.initials: MM
authors.lastname: Weigel
authors.affiliation: Department of Civil Engineering, The University of Texas at El Paso, El Paso, TX, 79968, USA.
authors.forename: Teresa
authors.initials: T
authors.lastname: Montoya
authors.affiliation: Facultad de Medicina, Universidad Central del Ecuador, Quito, Ecuador.
authors.forename: Patricia
authors.initials: P
authors.lastname: Eschanique
authors.affiliation: Facultad de Medicina, Universidad Central del Ecuador, Quito, Ecuador.
authors.forename: Marcia
authors.initials: M
authors.lastname: Racines
authors.affiliation: Department of Civil Engineering, The University of Texas at El Paso, El Paso, TX, 79968, USA.
authors.forename: Wen-Whai
authors.initials: WW
authors.lastname: Li
mesh_terms: D000293:Adolescent; D000393:Air Pollutants / Q000032:analysis*; D000397:Air Pollution / Q000032:analysis; D016902:Air Pollution, Indoor / Q000032:analysis*; D000531:Altitude; D002648:Child; D002947:Cities; D004484:Ecuador; D004781:Environmental Exposure / Q000032:analysis*; D004784:Environmental Monitoring; D006798:Housing; D006801:Humans; D010316:Particle Size; D052638:Particulate Matter / Q000032:analysis*; D011203:Poverty; D012111:Residence Characteristics; D012574:Schools; D001335:Vehicle Emissions
chemical_list: D000393:Air Pollutants; D052638:Particulate Matter; D001335:Vehicle Emissions
keywords: Air pollution; Indoor; Outdoor; Particulate matter; Public schools; Quito; Residences