AIR QUALITY CA

Air Quality in San Diego, CA: Moderate (51 AQI)

AQI 51 · Moderate · Ozone · Updated 2026-05-03

San Diego'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

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 Diego's average AQI of 51 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 Diego, 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 Diego

AQI varies across San Diego's 81 ZIP codes based on proximity to pollution sources and local geography.

ZIP Code	AQI	Category	Wildfire	Mold
92132	64	Moderate	84	23	View report →
92139	64	Moderate	85	37	View report →
92154	64	Moderate	84	39	View report →
92101	51	Moderate	49	27	View report →
92102	51	Moderate	80	48	View report →
92103	51	Moderate	80	40	View report →
92104	51	Moderate	80	40	View report →
92105	51	Moderate	85	45	View report →
92106	51	Moderate	80	48	View report →
92107	51	Moderate	80	48	View report →
92108	51	Moderate	80	37	View report →
92109	51	Moderate	80	49	View report →
92110	51	Moderate	80	43	View report →
92111	51	Moderate	80	40	View report →
92112	51	Moderate	80	23	View report →

Showing 15 of 20 ZIP codes. View all.

Air Quality Overview

San Diego, California has moderate air quality with an average AQI of 51. 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 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 Diego

AQI varies across San Diego's 81 ZIP codes based on proximity to pollution sources, traffic patterns, and local geography:

ZIP Code	AQI	Category	Wildfire Risk	Mold Score
92132	64	Moderate	84	23
92139	64	Moderate	85	37
92154	64	Moderate	84	39
92101	51	Moderate	49	27
92102	51	Moderate	80	48
92103	51	Moderate	80	40
92104	51	Moderate	80	40
92105	51	Moderate	85	45
92106	51	Moderate	80	48
92107	51	Moderate	80	48
92108	51	Moderate	80	37
92109	51	Moderate	80	49
92110	51	Moderate	80	43
92111	51	Moderate	80	40
92112	51	Moderate	80	23

Showing 15 of 81 ZIP codes. Check your specific ZIP for detailed data.

Wildfire Smoke Risk

San Diego has an elevated wildfire smoke risk with an average smoke risk score of 81 (scale 0-100). There have been 2,477 fires recorded within 100 km of city ZIP codes.

Metric	Value
Avg. smoke risk score	81
Max smoke risk score	86
Fires within 100 km	2,477
High-risk ZIP codes	81

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 Diego has an average mold risk score of 29 out of 100.

Factor	Value
Mold risk score	29/100
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 51), 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 Diego vs. Nearby California Cities

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

City	AQI	Category	Population
San Diego	51	Moderate	1,422,927
Alameda	54	Moderate	1,442,800
Albany	54	Moderate	1,442,800
Berkeley	54	Moderate	1,442,800

ZIP Codes in San Diego

San Diego covers 81 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 Diego?

San Diego's average AQI is 51 (Moderate). Air quality is acceptable, but unusually sensitive individuals may experience respiratory symptoms during peak pollution times.

How many unhealthy air days does San Diego have?

San Diego 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 Diego?

The average Air Quality Index (AQI) in San Diego is 51, categorized as Moderate. The primary pollutant is Ozone. 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 Diego?

San Diego has a wildfire risk score of 81 out of 100. High wildfire risk can significantly worsen air quality during fire season. Consider HEPA air purifiers and monitor AirNow.gov for real-time conditions.

Is mold a concern in San Diego?

San Diego has a mold risk score of 29 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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