The innovative concept of three-dimensional hybrid receptor modeling

- Three-dimensional PSCF and CWT for identification of source altitude distribution.
- New hybrid receptor model for pollutant altitude distribution along transport pathway.
- Refined approach for more realistic representation of source distribution.
- Potential PM2.5 source regions were registered in Romania, Bulgaria and Bosnia.
- Pollutant time series preprocessing to make models applicable for urban sites.

The aim of this study was to improve the current understanding of air pollution transport processes at regional and long-range scale. For this purpose, three-dimensional (3D) potential source contribution function and concentration weighted trajectory models, as well as new hybrid receptor model, concentration weighted boundary layer (CWBL), which uses a two-dimensional grid and a planetary boundary layer height as a frame of reference, are presented. The refined approach to hybrid receptor modeling has two advantages. At first, it considers whether each trajectory endpoint meets the inclusion criteria based on planetary boundary layer height, which is expected to provide a more realistic representation of the spatial distribution of emission sources and pollutant transport pathways. Secondly, it includes pollutant time series preprocessing to make hybrid receptor models more applicable for suburban and urban locations. The 3D hybrid receptor models presented herein are designed to identify altitude distribution of potential sources, whereas CWBL can be used for analyzing the vertical distribution of pollutant concentrations along the transport pathway.