Air quality reference
Snohomish County, Washington
US | 40 | Good | 2026-02-28T00:00:00+00:00
Key facts
- Location
- Snohomish County, Washington
- Air quality index
- 40
- Category
- Good
- Defining parameter
- PM2.5
- Sites reporting
- 3
- Measured at
- 2026-02-28T00:00:00+00:00
- Measurement context
- Daily AQI summary from U.S. EPA AirData; values are not direct pollutant concentrations
Historical air-quality context
Published EPA annual CBSA indicators
Annual AQI summaries are shown independently from pollutant concentrations. Current-year values are provisional because reporting is incomplete and can be revised.
Annual indicator
Days with published AQI
59.00 days2026
EPA annual county summary field: Days with AQI. Current-year values are provisional. Values retain the source period and unit.
View source data
| Period | days | Source flag | Confidentiality |
|---|---|---|---|
| 2026 | 59.00 days | provisional-current-year | — |
Annual indicator
Good AQI days
30.00 days2026
EPA annual county summary field: Good Days. Current-year values are provisional. Values retain the source period and unit.
View source data
| Period | days | Source flag | Confidentiality |
|---|---|---|---|
| 2026 | 30.00 days | provisional-current-year | — |
Annual indicator
Hazardous AQI days
0.00 days2026
EPA annual county summary field: Hazardous Days. Current-year values are provisional. Values retain the source period and unit.
View source data
| Period | days | Source flag | Confidentiality |
|---|---|---|---|
| 2026 | 0.00 days | provisional-current-year | — |
Annual indicator
Maximum daily AQI
107.00 AQI index2026
EPA annual county summary field: Max AQI. Current-year values are provisional. Values retain the source period and unit.
View source data
| Period | AQI index | Source flag | Confidentiality |
|---|---|---|---|
| 2026 | 107.00 AQI index | provisional-current-year | — |
Annual indicator
Median daily AQI
49.00 AQI index2026
EPA annual county summary field: Median AQI. Current-year values are provisional. Values retain the source period and unit.
View source data
| Period | AQI index | Source flag | Confidentiality |
|---|---|---|---|
| 2026 | 49.00 AQI index | provisional-current-year | — |
Annual indicator
Moderate AQI days
28.00 days2026
EPA annual county summary field: Moderate Days. Current-year values are provisional. Values retain the source period and unit.
View source data
| Period | days | Source flag | Confidentiality |
|---|---|---|---|
| 2026 | 28.00 days | provisional-current-year | — |
Annual indicator
90th percentile daily AQI
77.00 AQI index2026
EPA annual county summary field: 90th Percentile AQI. Current-year values are provisional. Values retain the source period and unit.
View source data
| Period | AQI index | Source flag | Confidentiality |
|---|---|---|---|
| 2026 | 77.00 AQI index | provisional-current-year | — |
Annual indicator
Unhealthy AQI days
0.00 days2026
EPA annual county summary field: Unhealthy Days. Current-year values are provisional. Values retain the source period and unit.
View source data
| Period | days | Source flag | Confidentiality |
|---|---|---|---|
| 2026 | 0.00 days | provisional-current-year | — |
Annual indicator
Unhealthy for sensitive groups days
1.00 days2026
EPA annual county summary field: Unhealthy for Sensitive Groups Days. Current-year values are provisional. Values retain the source period and unit.
View source data
| Period | days | Source flag | Confidentiality |
|---|---|---|---|
| 2026 | 1.00 days | provisional-current-year | — |
Annual indicator
Very unhealthy AQI days
0.00 days2026
EPA annual county summary field: Very Unhealthy Days. Current-year values are provisional. Values retain the source period and unit.
View source data
| Period | days | Source flag | Confidentiality |
|---|---|---|---|
| 2026 | 0.00 days | provisional-current-year | — |
Field-level provenance
Sources for this profile
Dates and licenses apply to the specific facts and series supplied by each source.
U.S. EPA AirData
- Applicable date
- 2026-02-28
- Dataset version
- 8f2c75a39c12
- License
- U.S. federal factual data; verify third-party fields
- Attribution
- U.S. EPA AirData
U.S. EPA AirData
- Applicable date
- 2026-08-02
- Dataset version
- 9648cf4436c9
- License
- U.S. federal factual data; verify third-party fields
- Attribution
- U.S. EPA AirData
Reference data can change. Verify consequential decisions against the original source.