Seattle air quality.
Air quality observations and historical context for Seattle, WA
Historical perspective
The longer view.
Annual PM2.5 concentrations · µg/m³
View data table
| Year | PM2.5 |
|---|---|
| 2019 | 6.9 |
| 2020 | 8.6 |
| 2021 | 5.9 |
| 2022 | 8.3 |
| 2023 | 7.2 |
| 2024 | 5.7 |
Available history: 2019–2024. Historical scores are distinct from current AQI and do not describe today’s conditions.
Sources and scoring method ↗Local context
How clean is Seattle air outside wildfire season?
Seattle often benefits from marine air, but wildfire smoke can quickly change the risk profile. This page shows annual PM2.5, trend direction, unhealthy-day estimates, and the indoor steps that matter when smoke reaches Puget Sound.
🌍 Live Air Quality in Seattle
Real-time pollutants resolved via none
Last 24 Hours: Seattle AQI Trend
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Live air quality data is currently unavailable for this specific location. You can check nearby cities below for representative regional readings.
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Regional Air Quality Context & Seasonal Patterns
Seattle is treated as a major metro in WA, so the most useful signal is the long-term pollution baseline rather than a single live AQI reading. Annual PM2.5 averages 5.7 ug/m3, with roughly 0 unhealthy-air days per year, and the multi-year trend is improving. Its Clean Air Score is 85.4 (grade A), which helps compare Seattle with other WA cities. In Seattle, historical EPA observations show that pollution levels typically peak in August (averaging an index of 36), while the cleanest air conditions occur in June (averaging 23). With an extreme events rating of 100/100, Seattle exhibits resilient atmospheric ventilation with fewer multi-day smoke outliers. This report uses direct city-level monitor coverage where available, so the trend is tied closely to conditions in Seattle.
Summer (Photochemical ozone & warm-season haze)
Historically lowest pollution baseline
Fine particulate matter (PM2.5) in Seattle is monitored for health safety. Long-term exposure to pollutants can lead to respiratory issues, making daily checks essential for active residents in WA.
Looking for cleaner air near Seattle?
These destinations have significantly higher historical Clean Air Scores than Seattle (Score: 85.4).
Anacortes, WA
Bremerton, WA
Mount Vernon, WA
Indoor Air Quality in Seattle, WA
Outdoor pollution can still affect indoor air when windows are open, filtration is weak, or wildfire smoke moves in.
Complete Seattle Home AQI & Filtration Guide
Get custom room-by-room HEPA purifier sizing, seasonal PM2.5 trends, and local home sealing recommendations.
Usually safe to open windows for fresh air.
Air purifier is optional for most households.
Normal indoor and outdoor activity is fine.
Ventilate selectively; sensitive groups should watch symptoms.
Run HEPA filtration on low if pollen, smoke smell, or traffic exhaust is noticeable.
Most people can continue normal activity; sensitive groups should keep an eye on AQI.
Keep windows closed so outdoor PM2.5 does not build indoors.
Run HEPA filtration in bedrooms and main living spaces.
Children, older adults, and people with asthma should reduce outdoor exertion.
Keep windows and doors sealed as much as practical.
Run filtration continuously; use the highest comfortable fan setting.
Stay indoors when possible and consider an N95 if you must go outside.
🛒Top Air Purifiers & Filters for Seattle
Given Seattle's air quality profile and peak pollution season in August, maintaining certified HEPA filtration indoors is an effective defense against fine particulate matter.
Levoit Core 300 True HEPA Air Purifier
Compact, ultra-quiet (<24dB), budget-friendly replacement filters.
Check price on AmazonCoway Airmega 200M True HEPA Air Purifier
Wirecutter top pick: high airflow, eco mode, washable pre-filter.
Check price on AmazonBlueair Blue Pure 311i+ Max Air Purifier
Extra carbon filtration for wildfire smoke and VOCs, smart app enabled.
Check price on AmazonCoway Airmega 400 True HEPA Air Purifier
Dual-suction Max2 filter for high smoke/pollen exposure in open spaces.
Check price on AmazonAs an Amazon Associate, Clean Air Data earns from qualifying purchases. Prices and availability shown on Amazon at time of purchase. This does not affect our air quality data or recommendations.
Health Recommendations
Most people can continue outdoor activities normally. Keep an eye on changing conditions.
Children and elderly should reduce prolonged or heavy outdoor exertion if AQI rises above 50.
Running & Outdoor Exercise Guide
Explore available hourly data before planning outdoor time in Seattle.
Environmental Health Dossier: Air & Tap Water in Seattle
Atmospheric fine particulate matter (PM2.5) and municipal drinking water contaminants represent the two primary involuntary daily exposures in any household. While HEPA filtration purifies indoor air, municipal tap water often contains invisible halogenated byproducts, heavy metals, or PFAS forever chemicals.
Seattle holds a historical Clean Air Score of 85.4/100. High PM2.5 requires True HEPA (H13) physical media filters without electronic ozone generation.
Municipal utility compliance focuses on legal limits, not health guidelines. Verified solid-carbon or Reverse Osmosis filters target lead, chlorine byproducts, and micropollutants.
Compare Seattle Air Quality
See how Seattle’s pollution baselines and seasonal patterns compare side-by-side.
Frequently Asked Questions about Seattle Air Quality
Is air quality in Seattle safe today?
Current air quality in Seattle is being monitored. Based on historical data, Seattle has a clean air score of 85.4. For real-time updates, check the live monitoring panel on this page.
When is air pollution highest in Seattle?
According to multi-year EPA observations, air pollution in Seattle historically peaks during August (Summer (Photochemical ozone & warm-season haze)). The cleanest air window typically occurs in June.
What should sensitive groups do during peak air pollution in Seattle?
Sensitive groups and outdoor runners should prioritize early morning activity before midday heat and ground-level ozone accelerate. Maintaining certified indoor HEPA filtration is an effective way to minimize personal exposure.
What is a dangerous AQI level?
An AQI (Air Quality Index) above 100 is considered unhealthy for sensitive groups, while levels above 150 are unhealthy for everyone. Levels above 300 are hazardous.
Should I wear a mask today in Seattle?
If the AQI in Seattle is above 150, an N95 mask is recommended for outdoor activities to filter out fine particulate matter (PM2.5).
Higher historical scores in WA
Major Hubs
Seattle AQI Widget
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