Environmental Engineering Reference
In-Depth Information
Lagorio et al. ( 2006 ) conducted a hospital-based study to evaluate whether expo-
sures to air pollutants in Rome, including PM 2.5 and associated selected metals (Cd,
Cr, Fe, Ni, Pb, Pt, and V), had a measurable impact on the lung function of adult
subjects aged 40-64 years who possessed pre-existing pulmonary or cardiovascular
conditions. Three panels consisting of 12 patients with chronic obstructive pulmo-
nary disease (COPD), 11 patients with asthma, and 9 patients with ischemic heart
disease (IHD), who had not smoked for at least a 1 year, participated in the study.
The study took place over a total of 67 days in 1999 (May to June and November to
December) during periods of high variability in air pollutant concentrations.
Pulmonary function tests were performed on each subject every 3 days during the
study periods. Sixty-two 24-h samples of PM 2.5 and PM 10 were collected at two
fi xed monitoring locations, representing a low and a high traffi c area in Rome, and
were quantifi ed for Cd, Cr, Fe, Ni, Pb, Pt, V, and Zn.
Amongst COPD patients, a 10
g/m 3 increase in PM 2.5 was signifi cantly corre-
lated with a 1.1% decrease in forced vital capacity (FVC) and a 1.06% decrease in
forced expiratory volume (FEV) based on the mean concentration of PM 2.5 for the
previous 3 days. Zn showed the most consistent associations with decrements in
FVC and FEV, and was also the metal most highly correlated with PM 2.5 concentra-
tions. The authors stated that Fe and Ni had less consistent associations with pulmo-
nary function, and the concentrations of these metals were moderately correlated
with PM 2.5 . The overall mean concentrations of PM 2.5 Ni (4.8 ng/m 3 ), Fe (283 ng/
m 3 ) and Zn (45.8 ng/m 3 ), along with a mean PM 2.5 concentration of 27.2
ʼ
g/m 3 ,
appeared to be threshold exposure levels that were correlated with decreased pul-
monary function parameters amongst patients with COPD. Changes in PM 2.5 (or
metal constituents) appeared to have no effects on pulmonary function parameters
in the asthmatic and IHD patients.
To put the ambient exposures in perspective, average levels of PM 2.5 recorded in
the U.S. (Table 1 ) ranged from 5.4 to 12.5
ʼ
g/
m 3 in Rome. Similarly, average concentrations of the metals of interest—Ni, Fe, and
Zn—are many times lower in U.S. ambient air as compared to Rome. A few aspects
of this study that must be interpreted with caution include the small number of sub-
jects, the relatively minor changes (less than 1%) in FVC and FEV, and the infl uence
of unaccounted for individual health factors on the responses being measured.
ʼ
g/m 3 , as compared to the level of 27.2
ʼ
Effects of PM Metals on Indicators of Cardiovascular Function
Urch and co-workers ( 2004 ) investigated the acute vascular effects of exposure to
CAPs (approximately 10× ambient levels) from Toronto plus ozone as compared to
fi ltered air, by measuring changes in brachial artery diameter in 24 healthy adult
volunteers. This study used a cross-over design, in which each subject served as his/
her own control, being exposed to either fi ltered air or CAPs plus ozone for a 2-h
period on different occasions. The median and range of transition metals concentra-
tions (in ng/m 3 ) in the CAPs to which the volunteers were exposed are presented in
Table 5 . Linear regression revealed no statistically signifi cant associations with total
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