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. Tracy's average AQI of 46 falls in the "Good" range.

Air Quality Map: Tracy, 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 Tracy

AQI varies across Tracy's 5 ZIP codes based on proximity to pollution sources and local geography.

ZIP Code	AQI	Category	Wildfire	Mold
95304	48	Good	20	31	View report →
95376	48	Good	20	30	View report →
95377	45	Good	19	18	View report →
95378	45	Good	20	15	View report →
95391	45	Good	20	15	View report →

Air Quality Overview

Tracy, California has good air quality with an average AQI of 46. 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 Tracy

AQI varies across Tracy's 5 ZIP codes based on proximity to pollution sources, traffic patterns, and local geography:

Wildfire Smoke Risk

Tracy has an elevated wildfire smoke risk with an average smoke risk score of 20 (scale 0-100). There have been 85 fires recorded within 100 km of city ZIP codes.

Metric	Value
Avg. smoke risk score	20
Max smoke risk score	20
Fires within 100 km	85
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

Tracy has an average mold risk score of 22 out of 100.

Factor	Value
Mold risk score	22/100
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 46), Tracy 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

Tracy vs. Nearby California Cities

How Tracy's air quality compares to nearby cities:

ZIP Codes in Tracy

Tracy covers 5 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.