Environmental Engineering Reference
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Another study, also of interest in this context, was that of Lippmann et al. (2006). It noted the high
daily mortality associated with PM 10 in New York City (NYC) in the 90-city National Mortality and
Morbidity Air Pollution Study (NMMAPS), and showed that in those 60 cities with speciation data,
only Ni and V were signiicantly associated with NMMAPS mortality. The NMMAPS mortality
coeficient for NYC was 3.8 times higher than the average and the Ni in NYC was 9.5 times higher
than the U.S. average.
Dominici et al. (2007) extended this analysis of NMMAPS data in relation to PM 2.5 speciation
in terms of additional cities and years of data and conirmed the associations of daily mortality
coeficients with Ni and V, but noted that with the exclusion of the NYC data, the overall association
was no longer statistically signiicant.
Lipfert et al. (2006) found V and Ni to be signiicantly associated with long-term mortality, but
that the trafic density variable was more robust and had larger explanatory value. Other studies also
point to trafic emissions and particular metals as both having signiicant associations with health
endpoints (Janssen et al., 2002; Grahame and Hidy, 2004).
Studies done largely in the absence of any but light trafic tend to show only the effects of
particular metals (Maciejczyk and Chen, 2005). It is important to recognize that studies that have
the capability of examining higher levels of both metals and of vehicular emissions tend to ind both
of health importance, and if the exposure to vehicular emissions is of good quality, tend to ind little
else of health signiicance (Ebelt et al., 2005; Gold et al., 2005; Schwartz et al., 2005).
Janssen et al. (2002), in a study on the inluence of air conditioning as a modiier of hospital
admission in relation to PM 10 concentrations, modeled source contributions to ambient air PM using
emissions data, rather than data from measured individual components. Cardiovascular admissions
were signiicantly associated with a number of sources (highway vehicles, oil combustion, and metal
processing), but there were no signiicant associations of the sources with COPD or pneumonia
admissions.
Franklin et al. (2008) modeled EPA air quality speciation data available for every third or sixth
day and daily mortality data for 25 U.S. cities between 2000 and 2005 to determine how the asso-
ciations between PM 2.5 and morality were modiied by PM 2.5 composition. They irst determined
the association between daily PM 2.5 and mortality, and then used meta-regression to examine how
the pooled association was modiied by community and by season-speciic PM 2.5 composition. The
association was increased when the PM 2.5 mass had a higher proportion of Al, As, SO 4 = , Si, and
Ni. The extent to which the intercity heterogeneity in the PM association could be explained by
was greatest for Al (45%), Ni (41%), and in a multivariate model by a combination of Al, Ni, and
SO 4 = or Al, Ni, and As (100%). These indings suggest that the sources of soil dust (indexed by Al,
Si), residual oil combustion (indexed by Ni), and coal combustion (indexed by As and/or SO 4 = ) are
especially inluential.
Zhou et al. (2011) obtained daily PM 2.5 ilters from Detroit and Seattle for the years 2002-
2004 and analyzed trace elements using XRF and BC using light relectance. They used Poisson
regression and distributed lag models to estimate excess hospitalization for all causes and for
cardiovascular and respiratory diseases, with adjustments for time-varying covariates. The PM 2.5
components and gaseous pollutants most closely associated with cardiovascular and respiratory
hospitalization in Detroit were secondary aerosols and trafic markers. In Seattle, the component
species most closely associated with hospitalization were those for cold season trafic and other
combustion sources, such as residual oil and wood burning.
Hsu et al. (2011) studied the inluence of components of PM 2.5 and PM 10 on heart rate and
pulmonary function on panels of COPD patients in NYC and Seattle. Nickel in NYC PM 2.5 was the
only component that produced a signiicant response, that is, an increase in heart rate.
In summary, a broad variety of cardiovascular and pulmonary health effects have been
signiicantly associated with peaks in ambient air concentrations of PM 2.5 and/or one or more of
its chemical components in a variety of large population cohort studies. These cohorts include
the thorough studies of morbidity and longevity in relation to ambient air concentrations of PM 10 ,
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