MOVES3 SCCs in 2016 platform onroad mobile?

I am looking at this mobile source inventory:

The SCCs are confusing to me. Is there a reason the SCCs do not follow the MOVES3 convention? (EPA_MOVES_Model/MOVES3CheatsheetOnroad.pdf at master · USEPA/EPA_MOVES_Model · GitHub) Specifically, the Process IDs in this inventory are not listed as Process IDs on this onroad cheatsheet.

I made this crosswalk based on the SCC desc file:


Can you explain why this was done? How are cold starts accounted for in the platform?

There are aggregate process IDs used in the SMOKE-MOVES process. The SCCs are rolled up to a lesser level of detail than MOVES uses because otherwise the emission factor tables would be huge. There are several process aggregations available – such as this one:

For the 2016 platform (pre-MOVES3), the starts are aggregated into the rest of the exhaust and evap emissions.

When we started using MOVES3 and the start activity data were broken out, starts are pulled out and treated separately.

this page ( might be useful.

It lists each MOVES process, the emissions mode, and the aggregated process code.

For processing MOVES3 outputs with separate rate-per-start factors, here are the process aggregation files used for each mode:

RPD: process_aggregation.csv

RPV: process_aggregation_rpv_no_rps.csv

RPP: process_aggregation.csv

RPH: process_aggregation.csv

RPS: process_aggregation.csv

RPHO: process_aggregation_rpho.csv

Without separate RPS factors:

RPD: process_aggregation.csv

RPV: process_aggregation_rpv.csv

RPP: process_aggregation.csv

RPH: process_aggregation.csv

The difference is in the rate-per-vehicle processing. The file process_aggregation_rpv_no_rps.csv leaves out the MOVES processes 2 (Start Exhaust) and 16 (Crankcase Start Exhaust). This ensures that those processes aren’t in the rate-per-vehicle outputs, and will only be in the rate-per-start outputs. It’s similar to how the rate-per-hour factors are split out; the RPV-specific aggregation file leaves out the extended idle processes (17, 90, and 91).

The same generic process_aggregation.csv file can get used for all the other modes (except RPHO) because there’s no duplication of MOVES outputs for the other modes, unlike rate-per-start and rate-per-hour.

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