In each country, the best available data from 1996
were used. The Australia PM10 models mostly used total
suspended particulate and NOx concentration data with
source-specific factors to estimate the exposure.10 The
French PM10 exposure models were based on the data
from a few sites for PM10 and an extensive monitoring
network for black smoke, a measurement method for
fine particulate matter from combustion sources. PM10
emission registries were available only for Switzerland,
enabling the adoption of emission-based dispersion
models which considered primary particulates,
secondary particles formed in the atmosphere from
precursor emissions, and transboundary large-scale PM.
With this emission-based model, we calculated PM10
distributions for total PM10 and traffic-related PM10
directly.10 Models were validated by measurements of
PM10 and the chemical composition of particulates at
several locations. For all three countries, results of the
emission-based Swiss study were used to derive the
traffic-related fraction of PM10 for Austria with
measurement data on the chemical composition of PM
and international modelling.10