Mercer Island, WA
Long-term air quality
What this page tells you
This page combines annual PM2.5, unhealthy days, 5-year trend, and data coverage so you can compare long-term air quality, not just today's reading.
Mercer Island, WA air quality summary: Mercer Island, WA, features an excellent clean air score of 85.4 and a grade of A. The city's annual mean for PM2.5 is recorded at 5.7. Mercer Island has an annual PM2.5 mean of 5.7, which is a moderate level near the lower end of the exposure scale. Long-term air quality in Mercer Island is improving over recent years.
Clean Air Score
A score of 85.4 and an A grade signify very good long-term air quality conditions. These metrics indicate that particulate matter levels are consistently low throughout the year, which is favorable for long-term residency.
🏡 What This Means for Buying
Mercer Island's air quality is a positive attribute for those evaluating long-term living environments. This data provides a strong baseline for people prioritizing a low-pollution residential setting.
Indoor Air Quality in Mercer Island, WA
Outdoor pollution can still affect indoor air when windows are open, filtration is weak, or wildfire smoke moves in.
How to react when today's AQI changes
Use the AQI bands below to decide whether to open windows, run an air purifier, or stay indoors when pollution spikes in Mercer Island.
AQI 0-50
GoodOpen windows: Open windows if you want fresh air.
Air purifier: No purifier needed for most homes.
Indoor activity: Normal indoor activity is fine.
AQI 51-100
ModerateOpen windows: Sensitive groups should limit open-window time.
Air purifier: Use fans or filtration if dust or pollen is bothering you.
Indoor activity: Most people can stay active indoors.
AQI 101-150
Unhealthy for Sensitive GroupsOpen windows: Keep windows closed.
Air purifier: Run a HEPA purifier in the main room and bedroom.
Indoor activity: Sensitive groups should reduce outdoor exposure.
AQI 151+
UnhealthyOpen windows: Keep windows and doors closed.
Air purifier: Run HEPA continuously and seal obvious drafts.
Indoor activity: Stay indoors as much as possible; use an N95 if you must go out.
Common indoor air concerns in Mercer Island:
- Wildfire smoke infiltration (PM2.5)
- Seasonal pollen and dust mite allergens
- VOCs from household products
Recommended action: If today's AQI reaches 101 or higher, close windows and run HEPA filtration before indoor air starts to feel smoky or stale.
Top Products for Mercer Island Homes:
🩺 My Health Risk Assessment
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Health Advice
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</> Create Free Widget🏡 Property Value Impact Analysis
Between 2019 and 2024, Mercer Island's air quality improved by 1.2 μg/m³. Based on NBER studies, this change correlates with a estimated 4.8% increase in relative property value retention.
Cleaner Alternatives in WA
Why Mercer Island earned a 85.4
Raw inputs, scoring weights, and data coverage for this city.
Best Time to Run
Find the cleanest hours for your run today.
Cycling Forecast
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📅 Past 30 Days Trend
Real-time daily PM2.5 AQI
🌸 Pollen Outlook
Current Seasonal Forecast
How it worksBased on current seasonal forecast data. Not a long-term pollution rating or relocation score.
Score Breakdown
| Component | Weight | Score Contribution |
|---|---|---|
| Annual Air Quality | 40% | 89.7 |
| Unhealthy Days | 25% | 100 |
| 5-Year Trend | 20% | 56 |
| Seasonal Variability | 10% | 95.5 |
| Extreme Events | 5% | 100 |
Explore More Air Quality Data
Frequently Asked Questions
About This Data
Data Sources
Historical air quality mapping and scoring are based completely on official U.S. Environmental Protection Agency (EPA) AirNow API data. 5-day AQI forecasts are provided by WAQI.
Methodology
Our Clean Air Score (0-100) is a proprietary algorithm that weighs multiple factors:
- Annual PM2.5 averages (40%)
- Frequency of unhealthy days (25%)
- 5-year pollution trends (20%)
- Seasonal variability and extreme events (15%)
Updates & Accuracy
Real-time data is updated hourly. Historical aggregate scores are recalculated monthly to reflect the latest trends. While we strive for accuracy, sensor maintenance and local conditions can affect individual readings.
Practical Advice
When AQI > 100: Sensitive groups (children, elderly, asthmatics) should limit prolonged outdoor exertion.
When AQI > 150: Everyone should avoid outdoor exercise and keep windows closed.
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Mercer Island Air Quality FAQs
Is Mercer Island a good fit for people who care about long-term air quality?
Mercer Island is an excellent option with a clean air score of 85.4 and a grade of A. The annual PM2.5 mean of 5.7 reflects low overall particulate exposure over the long term.
What is the frequency of unhealthy air or long-term pollution exposure in Mercer Island?
Mercer Island maintains an unhealthy days percentage of 0. This, combined with its A grade, suggests that residents are rarely exposed to elevated pollution levels.
Is air quality in Mercer Island improving or getting worse over time?
Air quality in Mercer Island has been improving over recent years. This positive long-term trend suggests a continued reduction in average particulate concentrations in the area.
How much does air quality vary within different parts of Mercer Island?
Air quality can vary within the city due to local traffic, industry, and location patterns. Local factors such as tree cover and proximity to the water can create slight variations in air quality across the island.