| Symptoms and Medication Use in Children with Asthma and Traffic-Related Sources of Fine Particle Pollution Janneane F. Gent,1 Petros Koutrakis,2 Kathleen Belanger,1 Elizabeth Triche,1 Theodore R. Holford,1 Michael B. Bracken,1 and Brian P. Leaderer1 1Center for Perinatal, Pediatric and Environmental Epidemiology, Department of Epidemiology and Public Health, Yale University School of Medicine, New Haven, Connecticut, USA; 2Harvard University School of Public Health, Boston, Massachusetts, USA Abstract
Background: Exposure to ambient fine particles [particulate matter ≤ 2.5 µm diameter (PM2.5) ] is a potential factor in the exacerbation of asthma. National air quality particle standards consider total mass, not composition or sources, and may not protect against health impacts related to specific components. Objective: We examined associations between daily exposure to fine particle components and sources, and symptoms and medication use in children with asthma. Methods: Children with asthma (n = 149) 4–12 years of age were enrolled in a year-long study. We analyzed particle samples for trace elements (X-ray fluorescence) and elemental carbon (light reflectance) . Using factor analysis/source apportionment, we identified particle sources (e.g., motor vehicle emissions) and quantified daily contributions. Symptoms and medication use were recorded on study diaries. Repeated measures logistic regression models examined associations between health outcomes and particle exposures as elemental concentrations and source contributions. Results: More than half of mean PM2.5 was attributed to traffic-related sources motor vehicles (42%) and road dust (12%) . Increased likelihood of symptoms and inhaler use was largest for 3-day averaged exposures to traffic-related sources or their elemental constituents and ranged from a 10% increased likelihood of wheeze for each 5‑µg/m3 increase in particles from motor vehicles to a 28% increased likelihood of shortness of breath for increases in road dust. Neither the other sources identified nor PM2.5 alone was associated with increased health outcome risks. Conclusions: Linking respiratory health effects to specific particle pollution composition or sources is critical to efforts to protect public health. We associated increased risk of symptoms and inhaler use in children with asthma with exposure to traffic-related fine particles. Key words: childhood asthma, fine particle pollution, PM2.5, respiratory morbidity, source apportionment, traffic pollution. Environ Health Perspect 117:1168–1174 (2009) . doi:10.1289/ehp.0800335 available via http://dx.doi.org/ [Online 31 March 2009]
Address correspondence to J.F. Gent, Yale Center for Perinatal, Pediatric and Environmental Epidemiology, One Church Street, 6th Floor, New Haven, CT 06510 USA. Telephone: (203) 764-9375. Fax: (203) 764-9378. E-mail: janneane.gent@yale.edu Supplemental Material is available online at http://www.ehponline.org/members/2009/0800335/suppl.pdf This study was funded by National Institutes of Health grants ES011013 and ES05410. The authors declare they have no competing financial interests. Received 29 October 2008 ; accepted 31 March 2009.
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