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Emissions development for HTAPv3 and EPA’s EQUATES Project
Citation:
Pouliot, G., K. Foley, A. Eyth, AND T. Keating. Emissions development for HTAPv3 and EPA’s EQUATES Project. International Technical Meeting on Air Pollution Modeling and its Application, Chapel Hill, NC, May 22 - 26, 2023.
Impact/Purpose:
EPA’s Air QUAlity TimE Series Project (EQUATES; www.epa.gov/cmaq/EQUATES) uses the state-of-the-science emissions, meteorological, and air quality methods and models to provide a unified set of modeling data for 2002-2017 to support regulatory and policy analyses as well as health and ecological studies. Modeled datasets cover the Conterminous US at a 12km resolution and the northern hemisphere at a 108km resolution using the Community Multiscale Air Quality modeling system version 5.3.2 (CMAQv5.3.2; https://www.epa.gov/CMAQ). New hemispheric and North American emissions inventories were developed using, to the extent possible, consistent input data and methods across all years, including emissions from mobile, fire, and oil and gas sources. The new emissions datasets and CMAQ output have been made publicly available to support a wide variety of human health and ecological applications. Model estimated trends will be used for dynamic and diagnostic evaluation of the CMAQ system to inform model development and build confidence in the use of the model for quantifying the impact of meteorological and emissions changes on air quality.
Description:
The EPA’s Air QUAlity TimE Series Project (EQUATES) includes a set of modeled meteorology, emissions, air quality, and pollutant depositions spanning the years 2002 through 2017 (https://www.epa.gov/cmaq/equates). The emission inventories developed for the US were mapped to the grid used for the Hemisperic Transport of Air Pollution (HTAP) mosaic version 3 dataset (https://edgar.jrc.ec.europa.eu/dataset_htap_v3). We will provide details on the development of the emission inventories over the US and to what extent we were able to develop consistent methodologies. There were 4 approaches for various sectors in the EQUATES inventory: use a new method for all years, use 2017 as a base year with activity data to scale back to 2002, use 2017 data constant for the whole time series, reuse existing inventories. In addition, we will show emission trends over the US for multiple pollutants and sources. We will show how the EQUATES inventories were estimated on the HTAPv3 mosaic grid, including any limitations and assumptions. We will also highlight the EQUATES emissions datasets that are publicly available and how they can be used in air quality modeling applications. The views expressed are those of the authors and do not necessarily represent the views or policies of the U.S. Environmental Protection Agency.