title: The Near-Road Exposures and Effects of Urban Air Pollutants Study (NEXUS): study design and methods.
abstract: The Near-Road Exposures and Effects of Urban Air Pollutants Study (NEXUS) was designed to examine the relationship between near-roadway exposures to air pollutants and respiratory outcomes in a cohort of asthmatic children who live close to major roadways in Detroit, Michigan USA. From September 2010 to December 2012 a total of 139 children with asthma, ages 6-14, were enrolled in the study on the basis of the proximity of their home to major roadways that carried different amounts of diesel traffic. The goal of the study was to investigate the effects of traffic-associated exposures on adverse respiratory outcomes, biomolecular markers of inflammatory and oxidative stress, and how these exposures affect the frequency and severity of respiratory viral infections in a cohort of children with asthma. An integrated measurement and modeling approach was used to quantitatively estimate the contribution of traffic sources to near-roadway air pollution and evaluate predictive models for assessing the impact of near-roadway pollution on children's exposures. Two intensive field campaigns were conducted in Fall 2010 and Spring 2011 to measure a suite of air pollutants including PM2.5 mass and composition, oxides of nitrogen (NO and NO2), carbon monoxide, and black carbon indoors and outdoors of 25 participants' homes, at two area schools, and along a spatial transect adjacent to I-96, a major highway in Detroit. These data were used to evaluate and refine models to estimate air quality and exposures for each child on a daily basis for the health analyses. The study design and methods are described, and selected measurement results from the Fall 2010 field intensive are presented to illustrate the design and successful implementation of the study. These data provide evidence of roadway impacts and exposure variability between study participants that will be further explored for associations with the health measures.
authors.affiliation: United States Environmental Protection Agency, National Exposure Research Laboratory, 109 TW Alexander Dr., RTP, NC 27711, USA. vette.alan@epa.gov
authors.forename: Alan
authors.initials: A
authors.lastname: Vette
authors.forename: Janet
authors.initials: J
authors.lastname: Burke
authors.forename: Gary
authors.initials: G
authors.lastname: Norris
authors.forename: Matthew
authors.initials: M
authors.lastname: Landis
authors.forename: Stuart
authors.initials: S
authors.lastname: Batterman
authors.forename: Michael
authors.initials: M
authors.lastname: Breen
authors.forename: Vlad
authors.initials: V
authors.lastname: Isakov
authors.forename: Toby
authors.initials: T
authors.lastname: Lewis
authors.forename: M Ian
authors.initials: MI
authors.lastname: Gilmour
authors.forename: Ali
authors.initials: A
authors.lastname: Kamal
authors.forename: Davyda
authors.initials: D
authors.lastname: Hammond
authors.forename: Ram
authors.initials: R
authors.lastname: Vedantham
authors.forename: Sarah
authors.initials: S
authors.lastname: Bereznicki
authors.forename: Nancy
authors.initials: N
authors.lastname: Tian
authors.forename: Carry
authors.initials: C
authors.lastname: Croghan
mesh_terms: D000293:Adolescent; D000393:Air Pollutants / Q000032:analysis* / Q000737:chemistry / Q000633:toxicity; D001249:Asthma / Q000150:complications / Q000453:epidemiology*; D015415:Biomarkers / Q000378:metabolism; D002478:Cells, Cultured; D002648:Child; D002947:Cities; D015331:Cohort Studies; D004784:Environmental Monitoring / Q000379:methods*; D006801:Humans; D007249:Inflammation / Q000139:chemically induced / Q000378:metabolism; D008824:Michigan / Q000453:epidemiology; D008962:Models, Theoretical; D018986:Motor Vehicles; D012141:Respiratory Tract Infections / Q000150:complications / Q000453:epidemiology / Q000821:virology; D053260:Soot / Q000032:analysis / Q000633:toxicity; D001335:Vehicle Emissions / Q000032:analysis* / Q000633:toxicity
chemical_list: D000393:Air Pollutants; D015415:Biomarkers; D053260:Soot; D001335:Vehicle Emissions