EPA Air · stack tests by county and year

Air-emissions stack tests in Snohomish County, Washington, 2025

• 42Stack tests

A stack test measures what a source actually emits, at the stack, against the limit in its permit. Each row below is one stack test recorded against a source in Snohomish County, Washington during 2025. A facility can appear several times: this is the year’s record of what happened, not a list of places. The sources themselves are on the Snohomish County facility page.

Snohomish County, Washington, 2025

• Inspections 210

Air-emissions stack tests in Snohomish County, other years

• 2026 5
• 2024 54
• 2023 37
• 2022 18
• 2021 16
• 2020 15
• 2019 20
• 2018 20
• 2017 28

Air-emissions stack tests recorded in Snohomish County, Washington, 2025

Dates as filed by the agency that recorded the stack test. Figures from EPA’s ICIS-AIR download.