Air Quality in Bellevue, WA: Moderate (64 AQI)
AQI 64 · Moderate · PM2.5 · Updated 2026-05-03
Bellevue's air quality is moderate. Unusually sensitive people should consider reducing prolonged outdoor exertion.
Data: EPA AirNow, FEMA National Risk Index Last verified: 2026-05-03
What is AQI?
The Air Quality Index (AQI) is a standardized scale from 0 to 500 that measures air pollution levels. 0-50 is "Good," 51-100 is "Moderate," 101-150 is "Unhealthy for Sensitive Groups," and above 150 is "Unhealthy" for everyone. AQI tracks five major pollutants: ground-level ozone, particulate matter (PM2.5 and PM10), carbon monoxide, sulfur dioxide, and nitrogen dioxide. Bellevue's average AQI of 64 falls in the "Moderate" range.
Air Quality Map: Bellevue, WA
Each dot represents a ZIP code. Color indicates AQI level. Tap a dot for details.
Air Quality by ZIP Code in Bellevue
AQI varies across Bellevue's 7 ZIP codes based on proximity to pollution sources and local geography.
| ZIP Code | AQI | Category | Wildfire | Mold | |
|---|---|---|---|---|---|
| 98004 | 64 | Moderate | 20 | 43 | View report → |
| 98005 | 64 | Moderate | 20 | 49 | View report → |
| 98006 | 64 | Moderate | 20 | 52 | View report → |
| 98007 | 64 | Moderate | 20 | 49 | View report → |
| 98008 | 64 | Moderate | 21 | 54 | View report → |
| 98009 | 64 | Moderate | 20 | 36 | View report → |
| 98015 | 64 | Moderate | 20 | 36 | View report → |
Air Quality Overview
Bellevue, Washington has moderate air quality with an average AQI of 64. Air quality is acceptable, though some pollutants may be a concern for a small number of people who are unusually sensitive to air pollution. The dominant pollutant is PM2.5.
The Air Quality Index (AQI) is an EPA-standardized scale from 0 to 500. Values below 50 are "Good," 51-100 "Moderate," 101-150 "Unhealthy for Sensitive Groups," 151-200 "Unhealthy," 201-300 "Very Unhealthy," and above 300 "Hazardous."
Dominant Pollutant: PM2.5
PM2.5 (fine particulate matter) consists of particles smaller than 2.5 micrometers — about 30 times thinner than a human hair. These particles can penetrate deep into the lungs and enter the bloodstream.
Health effects of PM2.5 exposure:
- Short-term: coughing, shortness of breath, aggravated asthma
- Long-term: reduced lung function, cardiovascular disease, premature death
- Most vulnerable: children, elderly, people with heart or lung disease
Common sources in urban areas: vehicle exhaust, construction dust, industrial emissions, wildfire smoke, residential wood burning.
Air Quality by ZIP Code in Bellevue
AQI varies across Bellevue's 7 ZIP codes based on proximity to pollution sources, traffic patterns, and local geography:
| ZIP Code | AQI | Category | Wildfire Risk | Mold Score |
|---|---|---|---|---|
| 98004 | 64 | Moderate | 20 | 43 |
| 98005 | 64 | Moderate | 20 | 49 |
| 98006 | 64 | Moderate | 20 | 52 |
| 98007 | 64 | Moderate | 20 | 49 |
| 98008 | 64 | Moderate | 21 | 54 |
| 98009 | 64 | Moderate | 20 | 36 |
| 98015 | 64 | Moderate | 20 | 36 |
Wildfire Smoke Risk
Bellevue has an elevated wildfire smoke risk with an average smoke risk score of 20 (scale 0-100). There have been 130 fires recorded within 100 km of city ZIP codes.
| Metric | Value |
|---|---|
| Avg. smoke risk score | 20 |
| Max smoke risk score | 21 |
| Fires within 100 km | 130 |
| High-risk ZIP codes | 0 |
Wildfire smoke contains PM2.5, carbon monoxide, and volatile organic compounds. Even short-term exposure can trigger asthma attacks and respiratory distress.
Indoor Mold Risk
Bellevue has an average mold risk score of 46 out of 100.
| Factor | Value |
|---|---|
| Mold risk score | 46/100 |
| Average humidity | 71% RH |
| High-risk ZIPs | 0 |
| Peak season | winter high |
Mold risk is influenced by humidity levels, housing age (older homes have more moisture issues), flood history, and water infrastructure quality. Indoor humidity above 60% creates favorable conditions for mold growth.
Signs of mold problems: musty odors, visible growth on walls or ceilings, worsening allergies indoors, condensation on windows. Professional mold testing ($300-$600) can identify hidden issues.
Health Recommendations
With moderate air quality (AQI 64), most people can be active outdoors. Sensitive groups should take precautions:
- Sensitive groups (asthma, COPD, heart disease): consider reducing prolonged outdoor exertion
- Keep windows closed on high-pollution days
- Use a HEPA air purifier in main living areas
- Check AirNow.gov before outdoor exercise
Bellevue vs. Nearby Washington Cities
How Bellevue's air quality compares to nearby cities:
| City | AQI | Category | Population |
|---|---|---|---|
| Bellevue | 64 | Moderate | 317,330 |
| Medina | 54 | Moderate | 317,330 |
| Airway Heights | 23 | Good | 343,167 |
| Nine Mile Falls | 23 | Good | 343,167 |
ZIP Codes in Bellevue
Bellevue covers 7 ZIP codes. Air quality can vary by neighborhood based on proximity to highways, industrial areas, and green spaces. Check your specific ZIP code for localized data.
Data Sources
- Air quality: EPA AirNow — real-time and historical AQI data
- Wildfire risk: FEMA National Risk Index
- Mold risk: Derived from EPA, FEMA, Census ACS (humidity, housing age, flood history)
- Monthly AQI: EPA Air Quality Statistics
Updated daily.