Health impact screening (HIS)
This method entails ascribing a so-called HIS score (health impact screening unique to the Netherlands), a colour and an environmental health quality on the basis of the magnitude of the environmental burden.
The score ranges between 0 (extremely good quality) and 8 (extremely poor quality). A score of 6 (insufficient quality) is the upper limit of permissible risk. This level is determined on the basis of policy standards and the most recent scientific dose–response relationships. Below this level the other HIS scores are derived in a logical sequence, thereby making the health assessment of different factors comparable to some extent.
The HIS score is depicted on a map by different colours (green, yellow, orange, red), so is easy to interpret. A separate map shows homes and other sensitive locations in the HIS colours.
This method is used to compare plan alternatives in terms of possible health impacts. It is suitable for various themes, including the assessment of differences in the health impacts of air pollution, noise nuisance, odour nuisance, external safety, electricity power lines and soil pollution. Its advantage is that it reveals bottlenecks. In addition, it uncovers build-up because of the overlap of high HIS scores for different environmental factors. When applying the health impact screening method, it should be remembered that the classification into exposure classes may result in differences between alternatives being exaggerated or even disappearing. In addition, the health impacts of different environmental aspects cannot be totalled to give a single HIS score.