Summary

In this chapter we address several further impacts sometimes considered in environmental assessments:

• Visibility,

• Noise,

• Traffic congestion,

• Depletion of non-renewable resources,

• Accidents.

Of these only loss of visibility is due to air pollution. Nevertheless we will comment briefly on the other impacts, because they can be relevant as ancillary benefits for the cost–benefit analysis of some pollution abatement measures.

The chapter begins with a brief discussion of the loss of visibility due to air pollution, an impact that has been found to contribute several percent to the cost of air pollution in the USA, but that has not yet been evaluated in Europe. For noise and congestion we cite some typical values. Noise and traffic congestion clearly impose external costs. For some of the other categories it is not clear to what extent they are external costs. We do not discuss the question of externalities related to employment or energy supply security. But we do have a section on depletion of non-renewable resources, because that category is important in most LCA methods.

Visibility

The most visible impact of air pollution is a loss of visibility. Three indicators are in common use for measuring visibility: standard visual range (SVR), light extinction and deciviews. Light extinction states what fraction of light is lost per meter due to absorption and/or scattering. Standard visual range is inversely proportional to light extinction. Since these two quantities are directly related to the absorption and scattering properties of the constituents of the atmosphere, their change due to air pollution can be calculated from atmospheric models. However, a change in SVR is not what matters for human perception, because perception is a nonlinear function of the light received by the eye. Like the ear, the eye perceives relative changes rather than absolute changes.