摘要：Policy decisions on complex environmental risks often involve contested science.
Typically there are no 'facts' that entail a unique correct policy. The evidence
that is embodied in scientific policy advice requires quality assessment. Advice
should be relevant to the policy issue, scientifically tenable and robust under
societal scrutiny. In 2003, the Netherlands Environmental Assessment Agency
adopted a standardized method, referred to as 'guidance', whereby key quality
aspects of knowledge production and use are exhibited through a checklist for
uncertainty assessment and communication. Although the guidance is not fully used
within all projects yet, it is increasingly used, attitudes towards dealing with
uncertainty in performing and reporting environmental assessments have changed,
and communication on uncertainty in the agency's reports has improved over
the past five years. In this letter, we present results from the application of the
guidance to controversies on the risks of ambient particulate matter. The active
deliberation on uncertainty in the policy–advisory setting brings about a joint learning
process for advisors and policy makers, which leads to a deeper understanding and
increased awareness of the phenomenon of uncertainty and its policy implications.
