TM5-ePMI

The equivalent Total Particle Emission index module (ePMI) based on the TM5-MP global transport model

TM5-ePMI is a tool designed to asses how much local anthropogenic emissions from different sectors contribute to the total particle mass and number concentrations locally under different idealized condition.

TM5-ePMI was developed as a part of the EU Horizon project PAREMPI [parempi.eu] and a full description of the model and it's component is available as Deliverable 3.4

The repository contains the fortran source code in /src which is a mix of heavily modified TM5-MP source code and custom ePMI code. It is not possible to compile TM5-MP with this code alone. In /preprocess there is a python script with an helper function to get emissions based on a emission inventory, and an example use case. In /postprocess there are two example python scripts that plots various parts of the general output.

TM5-ePMI is a single column version of TM5-MP (Williams et al., 2017) that models:

• Gas phase chemistry with the modified Carbon Bond 5 mechanism (Yarwood et al., 2005)
• Gas/particle partitioning model EQSAM (Metzger et al., 2002)
• Aerosol dynamics with the modal M7 module (Vignati et al., 2004)
• Dry deposition and sedimentation (Aan de Brugh et al., 2011)
• Vertical mixing in the boundary layer (Holtslag and Boville, 1993)

In addition, TM5-ePMI includes the following:

• A novel SOA parametrization from aromatics
• Ammonia - sulfuric acid new particle formation lookup table (Svenhag et al., 2024)
• Updated representation of emissions from traffic sector:
  • Primary ultra fine particles tail pipe emissions (Lintusaari et al., 2023)
  • PM2.5 and PM10 Non-exhaust emissions

TM5-ePMI does not model the advection of tracers. Instead the model is initialized with values representative of the background concentrations, and run as a stationary column with local emissions for a short period (24 hours or less is recommended). I.e. it is assumed that the local emissions stay within the local region throughout the simulation.

The meteorology is also simplified but designed to be flexible in order to test different idealized scenarios such as stability or boundary layer min/max height.