In recent years large efforts have been devoted in EU-funded research

projects,

i.e. the ExternE-projects, to the development of an approach that can be used

to

estimate the external costs of air pollution. The calculation in these

projects is

based on the so called Impact pathway approach where the impacts from air

pollution are assessed and valued. This approach has now been used to

estimate

the cost of air pollution of transport in Sweden for the year 2000. In

addition, we

have used abatement cost estimates to include the costs due to acidification

and

eutrophication. This is a joint project between VTI, TFK and IER at the

University of Stuttgart. This report presents and discusses the results from

this

project, "the all-modes study", regarding air pollutants with a local and

regional

dispersion. It also relates the results from this project to cost estimates

in other

studies.

Cost estimates have been calculated for all transport modes. For road

transport,

estimates were calculated for extra urban and urban traffic and also for two

cases,

Skellefteå and Stockholm. The purpose was to obtain information on the

variation

in costs between different traffic situations. Such information is an input

in the

evaluation of infrastructure investments and is also a basis for marginal

cost

pricing. The costs vary since there is a large number of variables that

influence the

estimates. Costs will depend upon which pollutant we consider and where the

emissions occur. Costs will also depend upon other relationships such as the

number of people being asthmatics in a population and the value placed on an

asthma attack. For the latter, the assumptions used in the all-modes study

are the

same as those used in the EU-funded UNITE-project.