title: Within-microenvironment exposure to particulate matter and health effects in children with asthma: a pilot study utilizing real-time personal monitoring with GPS interface.
abstract: Most particulate matter (PM) and health studies in children with asthma use exposures averaged over the course of a day and do not take into account spatial/temporal variability that presumably occurs as children move from home, into transit and then school microenvironments. The objectives of this work were to identify increases in morning PM exposure occurring within home, transit and school microenvironments and determine their associations with asthma-related inflammation and rescue medication use.
  
  
  
  In 2007-2008, thirty Denver-area schoolchildren with asthma performed personal PM exposure monitoring using a real-time sensor integrated with a geographic information system (GIS) to apportion exposures to home, transit and school microenvironments. Concurrently, daily monitoring of the airway inflammatory biomarker urinary leukotriene E4 (uLTE4) and albuterol usage was performed.
  
  
  
  Mean PM exposures each morning were relatively well correlated between microenvironments for subject samples (0.3 < r < 0.8), thus limiting use of this exposure metric to attribute health effects to PM exposure in specific microenvironments. Within-microenvironment increases in exposure, such as would be characterized by one or a series of transient spikes or a sustained increase in concentration (exposure event), however, were not strongly correlated between microenvironments (|r| < 0.25). On days when children were exposed to a ≥ 5μg/m3exposure event during transit, they demonstrated a 24.0 % increase in uLTE4(95 % CI: 1.5 %, 51.5 %) and a 9.7 % (-5.9 %, 27.9 %) increase in albuterol usage compared to days without transit exposure events. Associations between exposure events and health outcomes in home and school microenvironments tended to be positive as well, but weaker than for transit.
  
  
  
  School children with asthma moving across morning microenvironments experience spatially heterogeneous PM exposures with potentially varying health effects.
authors.affiliation: Department of Pediatrics, National Jewish Health, Denver, CO, USA.
authors.forename: Nathan
authors.initials: N
authors.lastname: Rabinovitch
authors.affiliation: Department of Environmental and Radiological Health Sciences, Colorado State University, Fort Collins, CO, USA.
authors.forename: Colby D
authors.initials: CD
authors.lastname: Adams
authors.affiliation: Division of Biostatistics and Bioinformatics, National Jewish Health, Denver, CO, USA.
authors.forename: Matthew
authors.initials: M
authors.lastname: Strand
authors.affiliation: Department of Environmental Health Sciences, Johns Hopkins University, Baltimore, MA, USA.
authors.forename: Kirsten
authors.initials: K
authors.lastname: Koehler
authors.affiliation: Department of Environmental and Radiological Health Sciences, Colorado State University, Fort Collins, CO, USA. john.volckens@colostate.edu.|Department of Mechanical Engineering, Colorado State University, 1374 Campus Delivery, Fort Collins, CO, 80523, USA. john.volckens@colostate.edu.
authors.forename: John
authors.identifier: 0000-0002-7563-9525
authors.initials: J
authors.lastname: Volckens
mesh_terms: D000293:Adolescent; D000393:Air Pollutants / Q000032:analysis*; D000420:Albuterol / Q000627:therapeutic use; D001249:Asthma / Q000188:drug therapy / Q000453:epidemiology* / Q000652:urine; D015415:Biomarkers / Q000652:urine; D002648:Child; D002947:Cities; D003120:Colorado; D003199:Computer Systems; D004784:Environmental Monitoring / Q000295:instrumentation / Q000379:methods*; D040362:Geographic Information Systems; D006801:Humans; D017999:Leukotriene E4 / Q000652:urine; D052638:Particulate Matter / Q000032:analysis*; D010865:Pilot Projects; D014584:User-Computer Interface
chemical_list: D000393:Air Pollutants; D015415:Biomarkers; D052638:Particulate Matter; D017999:Leukotriene E4; D000420:Albuterol
keywords: Aerosol; Air pollution; Epidemiology; Inflammation; Spatio-temporal