Assessing the cardiovascular effects of mail carriers from personal exposure to traffic related air pollutants
Date Issued
2008
Date
2008
Author(s)
Kuo, I-Chun
Abstract
Although traffic-related pollutants have been associated with increased cardiovascular mortality and affected the cardiovascular functions, most studies used the central site monitoring data as surrogates for personal exposure. To examine the associations between traffic-related air pollution and cardiovascular functions, we used the personal five-sized-fraction particular matter sampler (PCIS; cut point: 2.5, 1.0, 0.5 and 0.25 μm) and personal real-time ozone monitor to assess personal exposure. We recruited 18 healthy adults from the Sinjhuang Post Office in Taipei County, Taiwan. We sampled PM and ozone when they worked outside by motorcycles. In this exploratory study, the health endpoints of those subjects were postsample HRV indices and Cardiao-ankle vascular index (CAVI) as an arterial stiffness index. We used mixed-effect models to estimate the personal exposure from fixed-site data and also to estimate the health effects from personal particles and ozone exposure. The fixed site monitoring data underestimated personal PM exposure, especially for the small particles with diameter < 0.25μm (different ratio = 1.72). However, fixed site data overestimated personal ozone exposure (different ratio = -0.23). The models including fixed-site PM data, distance to the major road, wind speed, temperature were increased the correlation from 0.61 to 0.85 for small particles with aerodynamic diameter less than 0.25μm. Large particle only was associated significantly (p value <0.05) with temperature and relative humidity in the fixed-effect models after adjusting fixed-site PM data. The fixed site O3, CO, distance from fixed-site station or speed were chosen as the variables for estimate the real-time personal ozone exposure (r = 0.50). We also found that increased exposure to small particles (<0.25μm) was associated with decreased HRV indices but increased ozone exposure significantly was associated with increased SDNN. For a 17.46μg/m3 increase in PM <0.25µm, SDNN decreased 14.50%. However, ozone and PM between 1.0 to2.5μm were associated with increased Cardio-ankle vascular index (CAVI). An interquartile increase of 20ppb in the average ozone exposure was associated with 5.31% increase in CAVI. Different size-fraction PM and ozone exposure were associated with cardiovascular effects. Large PM, small PM and ozone have different pathway to affect the health response. The use of personal exposure improved the association between health outcomes and exposure and decrease the misclassification.
Subjects
personal exposure
exposure assessment
traffic-related pollutants
particular matter
submicrometer particles
ozone
cardiovascular effect
HRV
cardio-ankle vascular index
CAVI
arterial stiffness
Type
thesis
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