Integrated Criteria Document Fine Particulate Matter

The composition of fine particulate matter and the proportions of fine particulate matter, SO₂ and NO₂ in the air pollutant mix in the Netherlands have changed. In the present situation, the fine particulate and NO₂ concentrations are relatively high ; the SO₂ concentrations are relatively low. The present fine particulate matter is composed of approximately equal portions of primary and secondary aerosols. (Corrected) measurements show that the current Dutch recommended limits for PM₁₀ of 40 mug per cubic metre (annual mean) and 140 mug per cubic metre (daily mean) are exceeded throughout the Netherlands.

Dutch and American studies, carried out in air pollution situations somewhat characteristic of the new air pollutant mixture, showed 24-hour PM₁₀ concentrations of lower than 140 mug per cubic metre to be associated with various effects. One study also indicated the occurrence of effects in children at annual mean concentrations of around 40 mug per cubic metre. It was concluded that both recommended limits should be revised downwards. At the current Dutch exposure levels of PM₁₀ effects can occur. The emissions of primary and (precursors of) secondary fine particulate matter will further decrease as a result of existing policy and socio-economic scenarios. Reductions in fine particulate matter emissions (after 1990) have mainly taken place in industry ; almost no emission reduction is expected from sources contributing to episodes on a local scale (e.g. transportation).

The annual mean fine particulate matter concentration could possibly fall to well below 40 mug per cubic metre as a result of current policy, provided foreign emissions decrease by the same percentages as those in the Netherlands. After the completion of this document (April 1993) a number of (draft) publications appeared on the relationship between fine particulate matter and acute effects. The results of these studies further confirm the conclusions drawn up in the present document. The studies in question have not been described separately.