AAAR 36th Annual Conference October 16 - October 20, 2017 Raleigh Convention Center Raleigh, North Carolina, USA
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Particulate Exposures in Asthmatic Kids (PEAK): Differences between Ultrafine and Fine Particle Exposures in Baltimore, USA
KIRSTEN KOEHLER, Ehsan Majd, McCormack Meredith, Hansel Nadia, Johns Hopkins School of Public Health
Abstract Number: 463 Working Group: Health Related Aerosols
Abstract Particulate matter (PM) air pollution is known to exacerbate asthma symptoms in children; however, it is still unclear which metric (particle size, morphology or chemical composition) of PM is most relevant to respiratory health. Most studies have focused on the health impacts of fine PM (PM2.5; particles with diameter less than 2.5 μm), yet recent toxicological evidence suggests that health effects may be more strongly related to the ultrafine portion of PM exposure. Due to complexities of exposure assessment and the lack of a regulatory monitoring network for ultrafine particles (UFP), few epidemiologic studies have evaluated the relationship between UFP and respiratory health. The aim of this work is to determine which potentially modifiable factors of fine PM, including UFP, microenvironment, and peak exposure, are associated with respiratory effects among inner-city children with asthma. We have conducted personal exposure assessment to ultrafine and fine PM exposures in a panel of 15 children (to date; study target of 50 children) with asthma, each with 4 days of continuous monitoring of PM2.5 and UFP (10-s resolution), geographic location, biomarkers (urinary LTE4), and asthma symptoms. UFP was measured using a Partector (expressed as lung deposited surface area; CH Technologies) and fine PM mass was measured with a MicroPEM (expressed as mass concentration; RTI International). Inner-city children were exposed to levels of PM mass often exceeding WHO recommendations for PM2.5 in indoor air (24-hr mean: 7.2 μg/m3; range of 1-hr averages: 1-377 μg/m3). UFP exposures (24-hr mean: 39 μg2/cm3; range of 1-hr averages: 1-1413 μg2/cm3) typically varied over 2 orders of magnitude within 24-hours. PM2.5 and UFP were highly variable within-day, between-day and between-participant. Furthermore, PM2.5 and UFP were only weakly correlated (R2<0.3).