Environmental Engineering Reference
In-Depth Information
In a more recent study, Suh et al. (
2011
) evaluated associations between levels of
65 air pollutants measured in the Aerosol Research and Inhalation Epidemiology
Study and specifi c causes for hospital admissions in Atlanta, GA for Medicare recip-
ients 64 years of age or older from 1998 to 2006. These authors reported that the 24-h
concentrations of certain transition metals (viz., Cu, Fe oxides, Mn, Ti and Zn) were
associated with increased odds of hospital admissions for cardiovascular disease;
including ischemic heart disease, congestive heart disease and atrial fi brillation. No
information was provided on the concentrations of the individual transition metals.
3.2.2
Children
Other authors focused on the sensitive subpopulation of children, who are thought
to be especially susceptible to the effects of PM
2.5
(Binkova et al.
2004
; Kleinman
2000
; Miller et al.
2002
; Schwartz
2004
). Exposure to PM
2.5
has been linked to the
development of chronic respiratory disease, lung function changes, and exacerba-
tion of asthma in children. Three studies (Hirshon et al.
2008
; Ostro et al.
2009
;
Patel et al.
2009
) that specifi cally investigated associations between transition met-
als in ambient PM and respiratory symptoms in children are discussed below.
Patel et al. (
2009
) investigated associations between PM
2.5
Ni, V, and Zn concen-
trations and respiratory symptoms reported for children aged 2 years and younger
of African American and Dominican Republic heritage, living in Northern
Manhattan and the South Bronx. The study used generalized additive mixed effect
models to evaluate the effects of each metal alone and metals with co-pollutants for
each symptom-reporting period. The authors found signifi cant positive associations
between wheeze and Ni and V exposure, with the largest effect observed for Ni. An
increase of one interquartile range (IQR) unit concentration of Ni was related sig-
nifi cantly to a 28% increased probability of wheeze. The inclusion of co-pollutants
and removal of the highest 5% of Ni concentrations did not alter this relationship. V
and wheeze were only signifi cantly associated in the multi-pollutant model. Ni and
V remained signifi cantly associated with wheeze during the cold and fl u season. Zn
was signifi cantly negatively associated with cough during the cold and fl u season.
Average concentrations of Ni and V during cold and fl u season were 12 ng/m
3
and
3.3 ng/m
3
, respectively. These Ni concentrations were about 10 times the nationwide
(STN) mean for urban areas, and the V concentrations about 3 times (see Table
2
).
Ostro et al. (
2009
) investigated the effects of Cu, Fe, K, and Zn on hospital
admissions for respiratory symptoms in general and subcategories of pneumonia,
acute bronchitis, and asthma in children <5 years of age, and children aged
5-18 years for six counties in California. Poisson regression was used to evaluate
the effects of individual metals for each county using single-day lags of 0-3; and
results then were combined into a meta-analysis using a random-effects model.
Changes in concentrations of Cu, Fe, K and Zn were signifi cantly associated with
increases at 1 and 3-day lags in hospital admissions for all respiratory symptoms,
and for asthma, pneumonia, and acute bronchitis for children <19 years of age.
Average concentrations for these metals ranged from 7 ng/m
3
for Cu to 124 ng/m
3
for Fe. An excess risk of 4.7% for respiratory hospital admissions was found for Fe
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