Page 168 - Materials Chemistry, Second Edition

L1644_C04.fm Page 140 Tuesday, October 21, 2003 3:13 PM

Morbidity
This effect concerns the following primary and secondary pollutants: NO , SO ,
2
x
NH , CO, nitrate aerosol, sulphate aerosol and PM10. Possible impacts are, among
3
others, hospital visits, bronchodilator use and chronic cough.
Mortality
The effect of mortality can be expressed by fatal cases or years of life lost (YOLL),
as previously explained in Chapter 3. However, since in recent years researchers
have moved from studies based on fatal cases to YOLL (EC, 1995; EC 2000), YOLL
is used as endpoint in this study. Table 4.4 illustrates the highly important E-R
functions that use YOLL as endpoint.

For example the additional YOLL by sulphates are calculated in the following way:

0.0012 YOLL/(mg/m3) * 0.00082 mg/m3)/
functional unit * 423,000 pers.* 0.75 adults/pers. =
0.312 YOLL/ TWh

where Dc = 0,00082 (µg/m ) concentration increase/functional unit
3
Pop. = 423,000 pers. (population expressed as persons in region considered)
adults = 0.75 adults/pers. (percentage of population which age above 18 years)

Caution must be exercised in interpreting every epidemiological study because
any number of confusing variables may lead to invalid conclusions. For example, a
study may be biased because workers are compared with nonworkers (workers are
usually healthier) or because relative rates of smoking have not been accounted for,
or other variables that may be the actual causal agents may not even be hypothesized

TABLE 4.4
Mortality Functions Expressed in YOLL Due to Concentration Increments
(µg/m ) (IER, 1998)
3
Receptor Category Pollutant Formula
Adults: Percentage of Population with Age above 18

'chronic' YOLL PM10 / 0.00072 * Dc * Pop. * adults
Nitrates
Sulphates 0.0012 * Dc * Pop. * adults
'acute' YOLL SO 2 0.0719 * Dc * Pop. * b_m /100 * adults
PM10 / 0.04 * Dc * Pop. * b_m /100 * adults
Nitrates
Sulphates 0.0677 * Dc * Pop. * b_m /100 * adults
0.0648 * Dc * Pop. * b_m /100 * adults
NO x
b_m: baseline mortality
Source: IER (1998)

© 2004 CRC Press LLC