# Differences between NEI2011 and NEI2017 emissions for North America

**URL:** <https://forum.cmascenter.org/t/differences-between-nei2011-and-nei2017-emissions-for-north-america/2065>\
**Category:** Emissions Inventory\
**Created:** [February 11, 2021, 3:15pm UTC](https://forum.cmascenter.org/t/differences-between-nei2011-and-nei2017-emissions-for-north-america/2065 "2021-02-11T15:15:09Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![skunwar](https://avatars.discourse-cdn.com/v4/letter/s/9f8e36/32.png) [@skunwar](https://forum.cmascenter.org/u/skunwar)\
**Post date:** [February 11, 2021, 3:15pm UTC](https://forum.cmascenter.org/t/differences-between-nei2011-and-nei2017-emissions-for-north-america/2065/1 "2021-02-11T15:15:09Z")

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I was curious if the differences between NEI2011 and NEI2017 emissions sectors are significant enough to alter PM2.5 or O3 substantially in the US, Mexico and Canada. Are are any regions in North America where NEI emissions (for any emission sector) are significantly different between 2011 and 2017 emission years?

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**Author:** ![eyth.alison](https://avatars.discourse-cdn.com/v4/letter/e/7ab992/32.png) [@eyth.alison](https://forum.cmascenter.org/u/eyth.alison)\
**Post date:** [February 11, 2021, 4:29pm UTC](https://forum.cmascenter.org/t/differences-between-nei2011-and-nei2017-emissions-for-north-america/2065/2 "2021-02-11T16:29:05Z")

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There are substantial differences between 2011 and 2017 emissions – there are even some significant differences between 2016 and 2017 emissions.

Here is an example of a spreadsheet that compares 2011, 2014, and 2016 emissions at the state level which I believes also includes Canada and Mexico:

ftp://newftp.epa.gov/air/emismod/2016/v1/reports/2016v1\_2014v71\_2011v63\_state\_summary\_09-Oct-2019.xlsx

There are various summaries at other levels of detail in the same location of the FTP site.

The NEI TSD contains a national summary of differences between 2017 and 2014 and page 2-15

[https://www.epa.gov/air-emissions-inventories/2017-national-emissions-inventory-nei-technical-support-document-tsd](https://www.epa.gov/air-emissions-inventories/2017-national-emissions-inventory-nei-technical-support-document-tsd)

Please let us know if you have further questions.

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**Author:** ![skunwar](https://avatars.discourse-cdn.com/v4/letter/s/9f8e36/32.png) [@skunwar](https://forum.cmascenter.org/u/skunwar)\
**Post date:** [February 11, 2021, 11:14pm UTC](https://forum.cmascenter.org/t/differences-between-nei2011-and-nei2017-emissions-for-north-america/2065/3 "2021-02-11T23:14:08Z")

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Thanks @eyth.alison ! The differences between the years, especially from 2011en to 2014fd, were big drops for some of the Western US states I was interested in. I had been using 2016fh emissions input into CMAQ and getting lower-than-expected PM2.5 in Western US, so I wanted to use 2011 emissions as input and see how CMAQ performs.

The IWDW repository provided me only the 2D sectors and not the elevated emissions sectors in the folder USEPA\_2011el\_Premerged/2011ek/premerged:  
afdust\_adj/ ag/ agfire/ beis/ nonpt/ nonroad/ np\_oilgas/ othafdust\_adj/ othar/ othon/ pt\_oilgas/ ptegu/ ptfire3D/ ptnonipm/ rail/ rwc/

On the other hand, CMAS Warehouse ( [CMAS Warehouse \> SMOKE \> Output \> 2011ek\_db6v2\_v6\_11g \> 12US2 \> cmaq\_cb6](https://drive.google.com/drive/folders/1JERrVSgEw4f8eTZ9jNQFawENAT6Bq5TX)) has a merged ‘emis\_mole\_all’ 2D emissions folder and 3 inline emissions sectors ptfire, ptegu, othpt containing the inline\_mole\_\* emissions files but without the corresponding stacks files for 12US2 domain.Could I possibly get the **2011ek stack** files for the 3 elevated emissions sectors (ptfire, ptegu, othpt) from somewhere, so that I could test-run 2011ek emissions input in CMAQ?