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Air Quality Program

Air Emissions Inventory

An air emissions inventory is a listing of the amount of air pollution emitted by various sources. Every year, Ecology and the local air quality agencies inventory large businesses.  Every three years, Ecology inventories many additional sources such as motor vehicles, wood stoves, agriculture, outdoor burning, and natural sources. Several inventory summaries are available below.


Large Business Annual Inventory

The large business inventory is a summary of individual facility inventories compiled by local air agencies and Ecology. The agency responsible for each facility is noted in the spreadsheet. Contact the local air agency or Ecology office for questions and the most up-to-date information about individual facilities.

Washington Emissions Inventory Reporting System (WEIRS)

The Washington Emissions Inventory Reporting System (WEIRS) system was designed to capture the information that major (also known as air operating permit) sources are required to report annually. There are two versions of WEIRS: the training version and the production version. The training version of WEIRS allows sources to get familiar with the system without affecting data that will be reported to Ecology. The production version of WEIRS allows sources to update the data for annual reporting. Helpful resources and links are available below.

Instructional material:

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Comprehensive three-year inventory

The comprehensive three-year inventory was developed by Ecology. It includes the large business inventory and many other source types such as motor vehicles, wood stoves, outdoor burning, agriculture, and natural sources. Summary data from the comprehensive emissions inventory as well as technical documentation are available below. If you need more information, please use the Contact Us link at the bottom of this page.

Large Business Prevention of Significant Deterioration (PSD) Modeling Inventory

The Prevention of Significant Deterioration inventory includes large businesses for the minor source baseline dates and the years 2005-2008. It also includes information about using the inventories in a PSD analysis.

Other Links

Contact Us.


Download 2005 Large Business Emissions Summary

Large Business Emissions Inventory Assistance

Download 2005 Comprehensive Emissions Inventory Summary

Download PSD Modeling Inventory (ZIP File Format)

Small Business Assistance Links

PSD Permit Information

Air Operating Permits

Air Quality Data

Local Clean Air Agencies and Ecology Regional Offices