Dispersion Modelling

GRAL/GRAMM for Terrain Dispersion Modelling

For pollutant modelling in complex terrain, we use the GRAMM/GRAL model.

GRAL is a Lagrangian particle model specifically developed for dispersion in complex terrain and under low-wind conditions. This allows it to be used effectively for dispersion modelling in valleys. Additionally, it can simulate pollutant dispersion in built-up urban areas.

GRAMM is a prognostic mesoscale model used to calculate wind fields in complex terrain. These wind fields can then be used as direct input for the GRAL model.

EIA – The Air Quality Chapter in Capable Hands

An Environmental Impact Assessment (EIA) verifies whether a construction project complies with environmental protection regulations. In the air quality chapter, we demonstrate the impacts on air quality and define measures to protect the environment.

Using the GRAMM/GRAL dispersion model, we calculate pollutant exposure from nitrogen dioxide or particulate matter for projects subject to an EIA, such as roads, tunnel portals, parking structures, waste incineration plants, or other industrial facilities.

Assessment of Odour Immissions

For new construction or expansions of livestock farming or composting facilities, we assess odour immissions. We analyse the dispersion conditions in the vicinity of the structures or operations to determine whether critical weather conditions for odour nuisance exist—particularly cold air drainage flows—and how frequently they occur.

If required, we conduct temporary wind measurements using our own weather stations or simulate odour immissions using the specifically designed GRAMM/GRAL dispersion model.