All noise levels were calulated using the Nordic method for prediction
of road traffic noise revised 1996 (TemaNord report 525). The same
traffic flow data was used both for noise and air pollution
prediction.

The calulated parameter is the A-weighted day-evening-night level,
denoted Lden, and the unit is dB (re 2e-5 Pa).

The calulations are available as 2DM mesh files for the reference
years 2000, 2011 and 2018. For other years between 2000 and 2018 the
noise level can be estimated using linear interpolation.

The calculated noise levels have been truncated downwards to 25 dB
Lden and upwards to 75 dB Lden. Each node in the mesh file represents
a calculation receiver point 2 meter above ground, and other points on
the mesh can be calulated using interpolation.

2DM files can be opened in most GIS software, and the open source
library MDAL (https://github.com/lutraconsulting/MDAL) provides a C++
api that can load and manipulate 2DM files.
When the 2DM files are opened in GIS software SWEREF 99 TM (EPSG:3006) should be used as CRS.

Mikael Ogren
2024-02-20
mikael.ogren@amm.gu.se