AIR QUALITY CA

Air Quality in San Francisco, CA: Moderate (53 AQI)

AQI 53 · Moderate · PM2.5 · Updated 2026-07-18

San Francisco'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 Francisco's average AQI of 53 falls in the "Moderate" range.

Air Quality Map: San Francisco, 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 Francisco

AQI varies across San Francisco's 60 ZIP codes based on proximity to pollution sources and local geography.

ZIP Code	AQI	Category	Wildfire	Mold
94130	55	Moderate	12	50	View report →
94101	53	Moderate	12	29	View report →
94102	53	Moderate	12	49	View report →
94103	53	Moderate	12	31	View report →
94104	53	Moderate	12	46	View report →
94105	53	Moderate	12	22	View report →
94107	53	Moderate	12	26	View report →
94108	53	Moderate	12	46	View report →
94109	53	Moderate	12	46	View report →
94110	53	Moderate	12	49	View report →
94111	53	Moderate	12	41	View report →
94112	53	Moderate	12	49	View report →
94114	53	Moderate	12	46	View report →
94115	53	Moderate	12	46	View report →
94116	53	Moderate	12	49	View report →

Showing 15 of 20 ZIP codes. View all.

Air Quality Overview

San Francisco, California has moderate air quality with an average AQI of 53. 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 Francisco

AQI varies across San Francisco's 60 ZIP codes based on proximity to pollution sources, traffic patterns, and local geography:

ZIP Code	AQI	Category	Wildfire Risk	Mold Score
94130	55	Moderate	12	50
94101	53	Moderate	12	29
94102	53	Moderate	12	49
94103	53	Moderate	12	31
94104	53	Moderate	12	46
94105	53	Moderate	12	22
94107	53	Moderate	12	26
94108	53	Moderate	12	46
94109	53	Moderate	12	46
94110	53	Moderate	12	49
94111	53	Moderate	12	41
94112	53	Moderate	12	49
94114	53	Moderate	12	46
94115	53	Moderate	12	46
94116	53	Moderate	12	49

Showing 15 of 60 ZIP codes. Check your specific ZIP for detailed data.

Wildfire Smoke Risk

San Francisco has an elevated wildfire smoke risk with an average smoke risk score of 12 (scale 0-100). There have been 178 fires recorded within 100 km of city ZIP codes.

Metric	Value
Avg. smoke risk score	12
Max smoke risk score	22
Fires within 100 km	178
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 Francisco has an average mold risk score of 36 out of 100.

Factor	Value
Mold risk score	36/100
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 53), 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 Francisco vs. Nearby California Cities

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

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

ZIP Codes in San Francisco

San Francisco covers 60 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 Francisco?

San Francisco's average AQI is 53 (Moderate). Air quality is acceptable, but unusually sensitive individuals may experience respiratory symptoms during peak pollution times.

How many unhealthy air days does San Francisco have?

San Francisco 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 Francisco?

The average Air Quality Index (AQI) in San Francisco is 53, 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 Francisco?

San Francisco has a wildfire risk score of 12 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 Francisco?

San Francisco has a mold risk score of 36 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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