An official website of the United States government.

This is not the current EPA website. To navigate to the current EPA website, please go to This website is historical material reflecting the EPA website as it existed on January 19, 2021. This website is no longer updated and links to external websites and some internal pages may not work. More information »

Air Emissions Modeling

Biogenic Emission Sources

Biogenic emission sources are emissions that come from natural sources, and need to be accounted for in photochemical grid models, as most types are widespread and ubiquitous contributors to background air chemistry. Often only the emissions from vegetation and soils are included, but other relevant sources include volcanic emissions, lightning, and sea salt.
Biogenic emissions are typically computed using a model which utilizes spatial information on vegetation and land use and environmental conditions of temperature and solar radiation. The model inputs are typically horizontally allocated (gridded) data, and the outputs are gridded biogenic emissions which can then be speciated and utilized as input to photochemical grid models.
The EPA supports development of specific biogenic emissions tools. The links below provide access to those tools, landuse input data, and associated documentation.

Refer to the CMAS Center Spatial AllocatorExit page and use the link for Raster Tools on that page for instructions regarding access and use of the BELD4 data.