CNOSSOS-EU: Using a Median value will lead to a higher number of exposed people and dwellings
In December 2020, the EU commission published amendments on CNOSSOS-EU in report “C(2020) 9101 final”. These amendments are mainly based on the RIVM-2019-0023 report from August 2019, a new additional method for the calculation of population exposure is also described; something which we call method 3 – Median value.
In the original CNOSSOS document 2 methods are described, Method 1 – Most exposed façade and Method 2 – Length of representative façade. Method 1 is used for buildings that represent a single dwelling or 1 dwelling per floor. Method 2 is used for apartment buildings that have dwellings with a single façade exposed to noise.
The new Method 3 can be used for appartement buildings that have more than 1 façade exposed to noise, or for appartement buildings where no information on how many facades are exposed to noise is available. It will be difficult for authorities to create a dataset that distinguishes between a single façade exposed to noise and multiple facades exposed to noise. Therefore we believe Method 3 will be more frequently used. When we compare Method 2 with Method 3, it is obvious that Method 3 leads to a higher number of people and dwellings exposed to noise. For a comparison of the three methods see part 4 of our training webinars on CNOSSOS-EU in this YouTube video.