Air Quality in San Jose, CA: Good (48 AQI)
AQI 48 · Good · Ozone · Updated 2026-05-03
San Jose's air quality is good. Air pollution poses little or no risk.
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. San Jose's average AQI of 48 falls in the "Good" range.
How do wildfires affect air quality?
Wildfire smoke contains fine particulate matter (PM2.5) that can travel hundreds of miles and dramatically spike AQI readings. During fire season, even cities far from active fires can experience unhealthy air. HEPA air purifiers (rated for PM2.5) are the most effective indoor protection. Check AirNow.gov for real-time conditions during fire season.
Air Quality Map: San Jose, CA
Each dot represents a ZIP code. Color indicates AQI level. Tap a dot for details.
Air Quality by ZIP Code in San Jose
AQI varies across San Jose's 57 ZIP codes based on proximity to pollution sources and local geography.
| ZIP Code | AQI | Category | Wildfire | Mold | |
|---|---|---|---|---|---|
| 95101 | 48 | Good | 29 | 15 | View report → |
| 95103 | 48 | Good | 29 | 15 | View report → |
| 95106 | 48 | Good | 29 | 15 | View report → |
| 95108 | 48 | Good | 29 | 15 | View report → |
| 95109 | 48 | Good | 29 | 15 | View report → |
| 95110 | 48 | Good | 29 | 36 | View report → |
| 95111 | 48 | Good | 29 | 31 | View report → |
| 95112 | 48 | Good | 29 | 43 | View report → |
| 95113 | 48 | Good | 29 | 18 | View report → |
| 95115 | 48 | Good | 29 | 15 | View report → |
| 95116 | 48 | Good | 29 | 43 | View report → |
| 95117 | 48 | Good | 29 | 36 | View report → |
| 95118 | 48 | Good | 29 | 36 | View report → |
| 95119 | 48 | Good | 34 | 28 | View report → |
| 95120 | 48 | Good | 34 | 37 | View report → |
Showing 15 of 20 ZIP codes. View all.
Air Quality Overview
San Jose, California has good air quality with an average AQI of 48. This means air pollution poses little or no risk. The dominant pollutant measured is Ozone.
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: Ozone
Ground-level ozone forms when pollutants from cars, power plants, and industrial facilities react with sunlight. Unlike stratospheric ozone, ground-level ozone is harmful to breathe.
Health effects of ozone exposure:
- Irritation of the respiratory system
- Reduced lung function
- Aggravation of asthma and chronic lung diseases
- Increased susceptibility to respiratory infections
Peak times: Ozone levels are typically highest on hot, sunny afternoons. Exercise outdoors in the morning when levels are lower.
Air Quality by ZIP Code in San Jose
AQI varies across San Jose's 57 ZIP codes based on proximity to pollution sources, traffic patterns, and local geography:
| ZIP Code | AQI | Category | Wildfire Risk | Mold Score |
|---|---|---|---|---|
| 95101 | 48 | Good | 29 | 15 |
| 95103 | 48 | Good | 29 | 15 |
| 95106 | 48 | Good | 29 | 15 |
| 95108 | 48 | Good | 29 | 15 |
| 95109 | 48 | Good | 29 | 15 |
| 95110 | 48 | Good | 29 | 36 |
| 95111 | 48 | Good | 29 | 31 |
| 95112 | 48 | Good | 29 | 43 |
| 95113 | 48 | Good | 29 | 18 |
| 95115 | 48 | Good | 29 | 15 |
| 95116 | 48 | Good | 29 | 43 |
| 95117 | 48 | Good | 29 | 36 |
| 95118 | 48 | Good | 29 | 36 |
| 95119 | 48 | Good | 34 | 28 |
| 95120 | 48 | Good | 34 | 37 |
Showing 15 of 57 ZIP codes. Check your specific ZIP for detailed data.
Wildfire Smoke Risk
San Jose has an elevated wildfire smoke risk with an average smoke risk score of 30 (scale 0-100). There have been 343 fires recorded within 100 km of city ZIP codes.
| Metric | Value |
|---|---|
| Avg. smoke risk score | 30 |
| Max smoke risk score | 34 |
| Fires within 100 km | 343 |
| 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
San Jose has an average mold risk score of 24 out of 100.
| Factor | Value |
|---|---|
| Mold risk score | 24/100 |
| Average humidity | 57% 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 good air quality (AQI 48), San Jose residents can enjoy outdoor activities without significant restrictions. General tips:
- Monitor AQI during wildfire season for temporary spikes
- Use HEPA air purifiers indoors if you have respiratory conditions
- Maintain indoor humidity between 30-50% to prevent mold
San Jose vs. Nearby California Cities
How San Jose's air quality compares to nearby cities:
| City | AQI | Category | Population |
|---|---|---|---|
| San Jose | 48 | Good | 1,796,685 |
| Oakland | 54 | Moderate | 1,444,562 |
| Alameda | 54 | Moderate | 1,442,800 |
| Albany | 54 | Moderate | 1,442,800 |
ZIP Codes in San Jose
San Jose covers 57 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.