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Washington Emissions Inventory Reporting System (WEIRS)

Facilities that have an air operating permit must send their emissions data to us or local clean air agencies. We collect emissions data through the Washington Emissions Inventory Reporting System (WEIRS) to find out how much pollution is in the air and track the data.

Industrial facility emitting air pollution and steam into the air.

Collecting emissions data

Our WEIRS data collection system keeps track of information that facilities with air operating permits must report annually.

There are two versions of WEIRS. The training version of WEIRS allows facilities to test their emissions with the system without affecting data that they will report. The production version of WEIRS allows facilities to update their data for annual reporting.

About Washington's air emissions inventory

An air emissions inventory is a thorough, detailed estimate of criteria pollutants, the individual substances that form the criteria pollutants (called criteria precursors), and hazardous air pollutants.

Every year, facilities that have an air operating permit must send their emissions data to us or local clean air agencies. This is called a point source inventory. These sources include large industrial facilities (pulp mills, airplane manufacturers, cement manufacturers, landfills, power plants) and airports, as well as smaller industrial and commercial facilities.

Every three years, we calculate emissions data from other smaller sources, such as motor vehicles, wood stoves, outdoor burning, agriculture, and natural sources.

We use the Washington Emissions Inventory Reporting System to collect the data. We obtain emissions data from:

  • Counties: Adams, Asotin, Benton, Chelan, Columbia, Douglas, Ferry, Franklin, Garfield, Grant, Island, Kittitas, Klickitat, Lincoln, Okanogan, Pend Oreille, San Juan, Skagit, Spokane, Stevens, Walla Walla, Whatcom, Whitman, and Yakima.
  • Hanford.
  • Pulp mills and aluminum smelters.

Facilities outside the counties listed above should contact a local clean air agency for emissions inventory reporting requirements.