SPECIATE: EPA's Repository of Volatile Organic Gas and Particulate Matter Speciation Profiles of Air Pollution Sources

Highlights

Data must be up to date to ensure EPA is pursuing the best solutions for regulatory analysis of air quality.
Abt developed and for more than a decade has updated and maintained the SPECIATE database.
Abt is updating data, making it easier to access SPECIATE and expanding data sources.

The Challenge

The SPECIATE database is the U.S. Environmental Protection Agency’s (EPA) repository of volatile organic gas and particulate matter (PM) speciation profiles of air pollution sources. The data are used to guide regulatory analysis and need to be kept up-to-date to ensure EPA is pursuing the best solutions to maintain and improve air quality.

The Approach

Abt developed and for more than a decade has updated and maintained SPECIATE. These data provide the required inputs for chemical transport models and emission inventory estimates and may be used for source apportionment and air toxics emissions estimates. Through the efforts of Abt, working with a cross-EPA office SPECIATE Work Group, EPA updates the database every two to three years.

We also recently drafted guidelines for data developers and a workbook template to inform the research community about the content and quality considerations for SPECIATE data. The goal is to have these practitioners and stakeholders submit data that EPA can consider for inclusion.

The Results

Abt recently made improvements to the SPECIATE program, culminating in the release of a new version of the database, SPECIATE 5.0, in the summer of 2019. This update appends over 400 speciation profiles to the previous version, including an initial set of volatility basis set profiles to support primary organic aerosol semi-volatile partitioning and intermediate volatility secondary organic aerosol precursors in chemical transport models.

Some of the many uses of these source profiles include:

Creating speciated emissions inventories for regional haze, PM, greenhouse gas and photochemical air quality modeling.
Estimating hazardous and toxic air pollutant emissions from PM and organic gas primary emissions.
Providing input to chemical mass balance receptor models.
Verifying profiles derived from ambient measurements by multivariate receptor models.

Several other improvements were made to the database structure, species properties data and documentation. The new user-friendly browser greatly enhances access to the data and provides visualization of the profiles.