Page 303 - Materials Chemistry, Second Edition

L1644_C07.fm Page 275 Monday, October 20, 2003 12:10 PM

municipality in the region under study has the shape of a circle, the maximum area
2
allowed for one municipality lying in the center of all annuli (origin) is 314 km . If
2
the biggest municipality in the region comprises less than 314 km , this assumption
is valid.
The calculation of the radial population density has two problems: 1) the radial
population density in districts close to the sea is not independent of the direction in
which one looks (the population density at the coast falls down abruptly to r = 0
2
persons/km ) and 2) no data might be available for the municipalities lying 100 km
outside the regional borders of the region under study.
The first problem implies that the total population of all municipalities lying in
the considered annulus is divided by the area of the annulus. Thus, the fact that a
2
considerable area around the municipality has r = 0 persons/km (municipalities
close to the sea) is respected. Due to the absence of population living in the sea, the
overall population density of the annulus is reduced. In order to solve the second
problem for the calculation of the population density in the municipalities of the
area adjacent to the area of study for population, data on a district level are used
rather than the population data for the municipalities.
Because most districts are bigger than municipalities, uncertainties are intro-
duced. As discussed earlier, the area of every municipality is assumed not to exceed
a circle with a radius of 10 km if the municipality lies in the center of the circle.
The average area of districts definitely exceeds this value. This means that the
population density of the annuli is often determined by the entire population of one
district, even though this district extends over more than one annulus and therefore
should “assign” its population to more than one annulus. It is assumed, however,
that the uncertainties introduced are not too big because the average exceeding the
center circle is within a tolerable range. Moreover, this procedure is assumed to be
valid because it is only chosen to include the area adjacent to the region under study,
while the region is dealt with using a higher resolution, so the overall uncertainties
related to the radial population density are considered to be quite low.

7.4.3 EFFECT ANALYSIS TO TRANSFORM INCREMENTAL EXPOSURES
INTO DAMAGE ESTIMATIONS

The effect analysis links the results of the fate and exposure analysis to the damage
due to the emitted pollutant. This analysis is independent of the fate and exposure
analysis and based on epidemiological and toxicological studies as well as on
socioeconomic evaluation. See Chapter 3 and Chapter 4 for further details.
The effect factor represents the number of health incidences (like asthma or
cancer cases or restricted activity days) per person — exposure time concentration.
The dose–response and exposure–response functions used in this study are taken
from IER (1998) and Hofstetter (1998). In this study only carcinogenesis and
respiratory health effects are taken into account because they are considered to be
the main contributors to the overall human health effects due to environmental
pollution (Krewitt et al., 1998).
In order to aggregate different health effects into a single indicator, the disability
adjusted life years (DALY) concept developed by Murray and Lopez (1996) is

© 2004 CRC Press LLC