How to account for PM from Brake and Tire wear in scaling

I am using the Namelist cntrl file to scale PM components. There are the default aerosol components.

I have scale factors from MOVES for these default aerosol components but also for brake/tire wear.

Short of combining both brake and exhaust PM to come up with a scale factor (even though emission profile for brake is likely different from the exhaust), I am not sure what the best recommended practice would be.

What step would be best in this situation?


Hello ABI0010,

The Emission Control Interface namelist is meant to provide control over emissions scaling for files that are provided to CMAQ for input. If your onroad emissions are already lumped in with other emission sources (e.g. agriculture, cooking, solvents, etc.) then you will not be able to scale them separately.

If you have onroad mobile emissions in their own file, but exhaust and brake/tire wear are not separate, then you can scale them separately by creating rules that modify the ‘ALL’ selection under the stream column to just specify the mobile source file. You can view the tutorials here to get a better idea of how this would be done: CMAQ/ at master · USEPA/CMAQ · GitHub
In your case, the brake-tire wear factor will be mostly affecting the coarse mode while the exhaust factor will be mostly affecting the fine mode, so you may be able to get away with scaling these different components from the same mobile input stream.

If you have mobile exhaust emissions on one file and brake/tire wear on a different file, then you can scale all emissions from each stream according to their specific factor and you will have a better representation of the impact of the change.


Thanks for this response. Most helpful