Background: Higher ambient fine particulate matter (PM_2.5) levels can be associated with increased blood pressure and vascular dysfunction.Objectives: To determine the differential effects on blood pressure and vascular function of daily changes in community ambient- versus personal-level PM_2.5measurements.Methods: Cardiovascular outcomes included vascular tone and function and blood pressure measured in 65 non-smoking subjects. PM_2.5exposure metrics included 24 h integrated personal- (by vest monitors) and community-based ambient levels measured for up to 5 consecutive days (357 observations). Associations between community- and personal-level PM_2.5exposures with alterations in cardiovascular outcomes were assessed by linear mixed models.Results: Mean daily personal and community measures of PM_2.5were 21.9±24.8 and 15.4±7.5 μg/m³, respectively. Community PM_2.5levels were not associated with cardiovascular outcomes. However, a 10 μg/m³increase in total personal-level PM_2.5exposure (TPE) was associated with systolic blood pressure elevation (+1.41 mm Hg; lag day 1, p<0.001) and trends towards vasoconstriction in subsets of individuals (0.08 mm; lag day 2 among subjects with low secondhand smoke exposure, p=0.07). TPE and secondhand smoke were associated with elevated systolic blood pressure on lag day 1. Flow-mediated dilatation was not associated with any exposure.Conclusions: Exposure to higher personal-level PM_2.5during routine daily activity measured with low-bias and minimally-confounded personal monitors was associated with modest increases in systolic blood pressure and trends towards arterial vasoconstriction. Comparable elevations in community PM_2.5levels were not related to these outcomes, suggesting that specific components within personal and background ambient PM_2.5may elicit differing cardiovascular responses.

This work investigated the resuspension and subsequent translocation of particulate matter (PM) from carpeted flooring surfaces due to walking. In addition, the effect of HVAC systems and ceiling fans on mixing and/or translocation of resuspended PM was studied. Testing took place both in a residence with a well-worn, soiled carpet and in an environmental test chamber. Prescribed walking occurred with PM measurements taken at multiple sampling heights. Scanning electron microscopy (SEM) of carpet fibers was used to determine the fraction of dust available for resuspension. These data, in conjunction with resuspended mass concentrations from this study, were used to generate emission factors by particle size for walking on both new and worn carpet. Carpet loading does not affect the emission factor, indicating that the amount of resuspended PM is directly proportional to the available PM in the carpet. While relative humidity (RH) plays an important role in resuspension from new carpets, with high RH enhancing resuspension, it has the opposite affect with old carpets, with increased RH decreasing resuspension. With the HVAC system on, translocated particles 1.2 m horizontally from the source had number concentrations of approximately 20–40% of those at the source. With a ceiling fan on, extensive mixing was noted with little difference seen in particle resuspension by height. With the ceiling fan off, there was very little mixing present and particle size varied substantially by height.