SMOKE Emissions Modeling Instructions

Introduction

This page includes instructions for how to use the WAQS emissions modeling platforms for preparing inputs for CAMx and CMAQ. The WAQS modeling platforms include all of the scripts, software, and data required for preparing inputs to CAMx and CMAQ. The process for creating air quality model (AQM)-ready emissions starts with downloading the software and data packages for a modeling platform. The WAQS Base2011b modeling platform is used as an example here to describe how to prepare emissions for CAMx and CMAQ.

Emissions Processing Overview

The WAQS emissions are first processed for input to CAMx (CB06). CMAQ (CB05) emissions are then created by converting the CAMx emissions using post-SMOKE processing utilities. There are a few important details needed to understand how the processing streams differ for CAMx and CMAQ.

Natural vs. Anthropogenic Sources

All of the anthropogenic sources (e.g. onroad mobile, CEM point) are processed in SMOKE and output in CAMx binary format. All of the natural emissions sources, which include biogenics, windblown dust, seasalt, and lightning, are processed outside of SMOKE to CAMx binary format. Post-processing utility programs (camx-utils) are used to merge the natural and anthropogenic emissions to create AQM-ready files.

3-D PMDETAIL Fires for CMAQ

While both CMAQ and CAMx support in-line plume rise calculations, only CAMx supports in-line processing of the PMDETAIL fires used for the WAQS. For CMAQ, the PMDETAIL fire inventories must be processed to 3-dimensional files (i.e. vertically allocated) using SMOKE. A hybrid version of CMAQ is used to both calculate in-line plumes for the non-fire point sources (e.g. CEM points) and read in the 3-d fire emissions files.

Processing Schematics

Emissions Processing Software

• SMOKE is used to process the annual county total NEI and 3SAQS Oil and Gas inventories for input to CAMx and CMAQ. It is also used at the end of the CMAQ-processing stream to merge the low-level (surface) emissions with the 3-D PMDETAIL fire emissions.
• The CAMx Utility programs Mrglow and Mrgelev are used to combine the low level and elevated anthropogenic and natural emissions files, respectively. These utilities are required to combine files created with SMOKE (anthro) and outside of SMOKE (natural).
• CAMx2CMAQ is used to convert the CAMx low-level and elevated emissions files to CMAQ format. This program performs multiple functions: (1) convert CAMx gas and aerosol species to the CMAQ species; (2) append an hour to the end of each emissions file because CMAQ requires emissions with 25 hours of data in each file; and (3) change the file format from the CAMx binary to CMAQ netCDF format.

Processing Guidance by Model

The emissions processing for both AQMs starts with processing the data for CAMx with SMOKE. The sequence of post-processing utilities differs for each of the AQMs. Details of the processing for each model are provided below.

CAMx

1. Process the anthropogenic inventories with SMOKE, output the emissions in CAMx speciation (CB6r2 and CAMx aerosols). For the elevated source categories, use the SMOKE program Smkmerge to output CAMx-ready elevated source files. Merge all of the individual source categories (e.g. nonpoint, area O&G, C1C2rail) together with the program Mrggrid. Use the program Smk2emis to convert the Mrggrid output surface netCDF files to CAMx binary format.
2. Use the CAMx utility program Mrglow to combine the SMOKE output surface emissions with the biogenic, windblown dust, and sea salt emissions. The resulting output files are CAMx-ready low level emissions.
3. Use the CAMx utility program Mrgelev to combine the SMOKE output elevated source emissions with the fire and lightning NOx emissions. The resulting output files are CAMx-ready elevated emissions.

CMAQ