Health Effects of Metals in Ambient Air Particulate Matter - Aerosols: Measurement, Dosimetry, and Health Effects - page 360

14.2 REVIEW OF STUDIES OF THE EFFECTS OF PM

AND COMPONENTS IN HUMANS

14.2.1 i ntroduction
This review of human responses is focused on CAPs inhalation studies and their health effects, with
an emphasis on studies that identify the particle size ranges and components most closely associated
with the observed effects. Lung instillation studies involving PM suspensions of materials found
in ambient air have also been reviewed. Finally, reported associations between ambient air PM
size fractions and components and human health-related responses in natural settings have been
reviewed. These include studies of limited numbers of individuals where there is information related
to personal exposures and effects (panel studies) and larger-population studies that rely on central
site air monitoring data and grouped responses.

14.2.2 H uMan caP s i nHalation s tudies
Ghio et al. (2000) reported that the 2 h CAPs exposures in Chapel Hill, NC caused neutrophilic
inlammation in the lungs and increased ibrinogen levels in the blood. Of the soluble components
extracted from the air-sampling ilters, Fe, As, Se, and SO 4 = were highly correlated with the PM 2.5
mass concentration, while Ni and Cu were least correlated. In terms of biological responses, an
Fe/Se/SO = factor was associated with increased BALF percentage of polymorpho-neutrophils
(PMNs) and a Cu/Zn/V factor with increased blood ibrinogen. The increase in plasma ibrinogen
correlated with decreases in PMNs and platelets, consistent with a state of systemic inlammation
and increased platelet aggregation.
Normotensive, nonsmoking, healthy volunteers in Toronto, Ontario, Canada were exposed to
PM 2.5 CAPs and O 3 for which there were data on PM 2.5 composition. Brachial artery diameter (BAD),
an index of cardiovascular response, decreased 0.09 mm compared to FA. There were no signiicant
responses in endothelial-dependent low-mediated dilatation (FMD), endothelial-independent
nitroglycerin-mediated dilatation (NMD), or blood pressure (Brook et al., 2002; Urch et al., 2004).
The linear regression analyses of change in BAD in relation to PM 2.5 components yielded p-values
of 0.04 for OC, 0.05 for EC, 0.06 for Cd, 0.09 for K. The p-values were between 0.13 and 0.17 for
Zn, Ca, and Ni, and values were even larger for all of the other measured components. The p-value
for PM 2.5 as a whole was 0.40. In a follow-up study, there was a signiicant increase (6 mm Hg)
in diastolic blood pressure in those exposed to O 3 plus CAPs (p = 0.013). In relation to the PM 2.5
components, there was a signiicant association (p = 0.009) with OC, whereas the association with
PM 2.5 mass was not signiicant (p = 0.27). In this study, the EC and metals were not signiicantly
associated with BAD constriction or blood pressure (Urch et al., 2005).

14.2.3 s Hort -t erM r esPonses to a Mbient a ir PM i nHalation
e xPosures in H uMan P anel s tudies
A panel study by Sorensen et al. (2005) included 49 students in Copenhagen. Their personal
exposure to soluble V and Cr was associated with signiicant increases in oxidative stress and
DNA damage (as measured by 8-oxodG concentrations in lymphocytes). Other soluble metals
(Fe, Ni, Cu, and Pt) did not.
Lanki et al. (2006) studied the inluence of ambient air PM 2.5 component exposures on exercise-
induced ischemia in 45 elderly nonsmokers with stable coronary heart disease in Amsterdam (the
Netherlands), Erfurt (Germany), and Helsinki (Finland). Two PM 2.5 source classes (trafic and long-
range transport) were associated with ST-segment depression during submaximal exercise testing in
a clinical laboratory. In a multi-pollutant model, with which the authors were able to separate effects
of secondary SO 4 = from effects of vehicular emissions, only the trafic emissions were signiicantly
associated with the effect. The authors also examined whether potentially toxic transition metals