# Most appropriate way to combine EQUATES, NEI, air emissions modeling platforms

**URL:** <https://forum.cmascenter.org/t/most-appropriate-way-to-combine-equates-nei-air-emissions-modeling-platforms/5195>\
**Category:** Emissions\
**Created:** [September 9, 2024, 8:53pm UTC](https://forum.cmascenter.org/t/most-appropriate-way-to-combine-equates-nei-air-emissions-modeling-platforms/5195 "2024-09-09T20:53:46Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![lizroten](https://yyz1.discourse-cdn.com/flex027/user_avatar/forum.cmascenter.org/lizroten/32/4015_2.png) [@lizroten](https://forum.cmascenter.org/u/lizroten)\
**Post date:** [September 9, 2024, 8:53pm UTC](https://forum.cmascenter.org/t/most-appropriate-way-to-combine-equates-nei-air-emissions-modeling-platforms/5195/1 "2024-09-09T20:53:46Z")

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Hi folks,

I’m looking to create a continuous time series of GHG and other emissions from 2002 to 2022 at the county-level for mobile onroad sources by vehicle type and fuel type. My study area includes the Twin Cities metro area (greater Minneapolis-St. Paul). These are the data pieces I’ve gotten ahold of

- Air emissions modeling platform datasets, from years 2022, 2021, 2020, 2019, 2018, 2017, 2016, 2015, 2014, 2011, 2008, 2005
- Official NEI from years 2011, 2014, 2017, and 2020
- EQUATES from years 2002, 2005, 2008, 2011, 2014, and 2017

In instances where we have multiple data sources for the same year (2017, 2014, etc), which dataset should be used?

I am leaning towards using EQUATES for 2002-2017, NEI for 2020, and air emissions modeling for 2021 and 2022.

I am comfortable linearly interpolating between these years to create a full time series, but I want to ensure it is valid to do so given that there are various base years.

Edit: moved to “Emissions” category

Thanks!