The latest version of the GRAL dispersion model, 24.04, has been released and it includes several updates and bug fixes. GRAL, a Lagrangian dispersion model, is extensively used for simulating pollutant dispersion, and these updates are expected to enhance its reliability in various environmental scenarios.

   A significant fix in version 24.04 addresses an issue that caused incorrect concentration calculations within buildings. This bug, present since version 23.11, affected flat terrain and certain building configurations. Correcting this issue ensures that GRAL can provide more accurate simulations in urban settings where building interactions play an important role.

   Lakes Environmental Software has announced the acquisition of the CALPUFF atmospheric dispersion modelling system from Exponent. This transaction, confirmed on 5 May 2024, marks another step in the evolution of CALPUFF, a model widely used by researchers, environmental consultants, and regulatory agencies globally.

    CALPUFF is a US EPA Guideline model for all applications > 50km, it is also the guideline model for all near-field applications where the steady state assumption does not apply, i.e., complex terrain and complex meteorological environments (Sea breeze, boundary layers, etc.). In addition, it is a model widely used in odour modelling. The code of this model, while being publicized as "freely available," is not open source, as far as we know. Over the years, the ownership of the code has changed from SRC to TRC, Earth Tech, Exponent, and now Weblakes.