AIR QUALITY CA

Air Quality in Alameda, CA: Moderate (55 AQI)

AQI 55 · Moderate · PM2.5 · Updated 2026-07-18

Alameda'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. Alameda's average AQI of 55 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 by ZIP Code in Alameda

AQI varies across Alameda's 2 ZIP codes based on proximity to pollution sources and local geography.

ZIP Code	AQI	Category	Wildfire	Mold
94501	55	Moderate	25	43	View report →
94502	55	Moderate	25	28	View report →

Air Quality Overview

Alameda, California has moderate air quality with an average AQI of 55. 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 Alameda

AQI varies across Alameda's 2 ZIP codes based on proximity to pollution sources, traffic patterns, and local geography:

ZIP Code	AQI	Category	Wildfire Risk	Mold Score
94501	55	Moderate	25	43
94502	55	Moderate	25	28

Wildfire Smoke Risk

Alameda has an elevated wildfire smoke risk with an average smoke risk score of 25 (scale 0-100). There have been 8 fires recorded within 100 km of city ZIP codes.

Metric	Value
Avg. smoke risk score	25
Max smoke risk score	25
Fires within 100 km	8
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

Alameda 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 55), 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

Alameda vs. Nearby California Cities

How Alameda's air quality compares to nearby cities:

City	AQI	Category	Population
Alameda	55	Moderate	76,876
Bellflower	55	Moderate	77,396
Redondo Beach	55	Moderate	77,927
Folsom	58	Moderate	77,952

ZIP Codes in Alameda

Alameda covers 2 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 Alameda?

Alameda's average AQI is 55 (Moderate). Air quality is acceptable, but unusually sensitive individuals may experience respiratory symptoms during peak pollution times.

How many unhealthy air days does Alameda have?

Alameda 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 Alameda?

The average Air Quality Index (AQI) in Alameda is 55, 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 Alameda?

Alameda has a wildfire risk score of 25 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 Alameda?

Alameda 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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