AIR QUALITY CA

Air Quality in San Jose, CA: Moderate (57 AQI)

AQI 57 · Moderate · PM2.5 · Updated 2026-07-18

San Jose's air quality is moderate. Unusually sensitive people should consider reducing prolonged outdoor exertion.

Data: EPA AirNow, FEMA National Risk Index Last verified: 2026-07-18

Average AQI

Moderate

AQI Category

Wildfire Risk

Mold Score

ZIP Codes

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 57 falls in the "Moderate" 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.

Good (0-50) Moderate (51-100) USG (101-150) Unhealthy (151+)

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	57	Moderate	29	21	View report →
95103	57	Moderate	29	21	View report →
95106	57	Moderate	29	21	View report →
95108	57	Moderate	29	21	View report →
95109	57	Moderate	29	21	View report →
95110	57	Moderate	29	36	View report →
95111	57	Moderate	29	31	View report →
95112	57	Moderate	29	43	View report →
95113	57	Moderate	29	18	View report →
95115	57	Moderate	29	21	View report →
95116	57	Moderate	29	43	View report →
95117	57	Moderate	29	36	View report →
95118	57	Moderate	29	36	View report →
95119	57	Moderate	34	36	View report →
95120	57	Moderate	34	37	View report →

Showing 15 of 20 ZIP codes. View all.

Air Quality Overview

San Jose, California has moderate air quality with an average AQI of 57. 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 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	57	Moderate	29	21
95103	57	Moderate	29	21
95106	57	Moderate	29	21
95108	57	Moderate	29	21
95109	57	Moderate	29	21
95110	57	Moderate	29	36
95111	57	Moderate	29	31
95112	57	Moderate	29	43
95113	57	Moderate	29	18
95115	57	Moderate	29	21
95116	57	Moderate	29	43
95117	57	Moderate	29	36
95118	57	Moderate	29	36
95119	57	Moderate	34	36
95120	57	Moderate	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 27 out of 100.

Factor	Value
Mold risk score	27/100
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 moderate air quality (AQI 57), 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

San Jose vs. Nearby California Cities

How San Jose's air quality compares to nearby cities:

City	AQI	Category	Population
San Jose	57	Moderate	1,014,813
New Almaden	60	Moderate	1,039,920
Sacramento	54	Moderate	846,557
San Francisco	53	Moderate	836,321

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.

Frequently Asked Questions

Is the air safe to breathe in San Jose?

San Jose's average AQI is 57 (Moderate). Air quality is acceptable, but unusually sensitive individuals may experience respiratory symptoms during peak pollution times.

How many unhealthy air days does San Jose have?

San Jose has zero recorded unhealthy air quality days, which is excellent. Air quality can still vary seasonally due to wildfire smoke, pollen, or industrial activity.

What is the AQI in San Jose?

The average Air Quality Index (AQI) in San Jose is 57, categorized as Moderate. The primary pollutant is PM2.5. AQI ranges from 0-500, where 0-50 is Good, 51-100 Moderate, 101-150 Unhealthy for Sensitive Groups, and 151+ Unhealthy.

What is the wildfire risk in San Jose?

San Jose has a wildfire risk score of 30 out of 100. Low wildfire risk means smoke events are uncommon, but regional fires can still temporarily affect air quality.

Is mold a concern in San Jose?

San Jose has a mold risk score of 27 out of 100, based on humidity, precipitation, and temperature data. Maintain good ventilation and address any water intrusion promptly to prevent mold growth.

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