AIR QUALITY CT

Air Quality in Norwalk, CT: Good (49 AQI)

AQI 49 · Good · PM2.5 · Updated 2026-05-03

Norwalk's air quality is good. Air pollution poses little or no risk.

Data: EPA AirNow, FEMA National Risk Index Last verified: 2026-05-03

Average AQI

Good

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. Norwalk's average AQI of 49 falls in the "Good" range.

Air Quality Map: Norwalk, CT

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 Norwalk

AQI varies across Norwalk's 11 ZIP codes based on proximity to pollution sources and local geography.

ZIP Code	AQI	Category	Wildfire	Mold
06850	50	Good	11	58	View report →
06851	50	Good	11	58	View report →
06853	50	Good	11	66	View report →
06854	50	Good	11	63	View report →
06855	50	Good	11	64	View report →
06856	50	Good	11	42	View report →
06858	50	Good	11	34	View report →
06859	50	Good	11	34	View report →
06852	48	Good	11	42	View report →
06857	48	Good	11	34	View report →
06860	48	Good	11	34	View report →

Air Quality Overview

Norwalk, Connecticut has good air quality with an average AQI of 49. This means air pollution poses little or no risk. The dominant pollutant measured 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 Norwalk

AQI varies across Norwalk's 11 ZIP codes based on proximity to pollution sources, traffic patterns, and local geography:

ZIP Code	AQI	Category	Wildfire Risk	Mold Score
06850	50	Good	11	58
06851	50	Good	11	58
06853	50	Good	11	66
06854	50	Good	11	63
06855	50	Good	11	64
06856	50	Good	11	42
06858	50	Good	11	34
06859	50	Good	11	34
06852	48	Good	11	42
06857	48	Good	11	34
06860	48	Good	11	34

Wildfire Smoke Risk

Norwalk has an elevated wildfire smoke risk with an average smoke risk score of 11 (scale 0-100). There have been 33 fires recorded within 100 km of city ZIP codes.

Metric	Value
Avg. smoke risk score	11
Max smoke risk score	11
Fires within 100 km	33
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

Norwalk has an average mold risk score of 48 out of 100, with 5 ZIP codes in the high-risk category.

Factor	Value
Mold risk score	48/100
Average humidity	68% RH
High-risk ZIPs	5
Peak season	summer 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 49), Norwalk 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

Norwalk vs. Nearby Connecticut Cities

How Norwalk's air quality compares to nearby cities:

City	AQI	Category	Population
Norwalk	49	Good	40,356
New Canaan	56	Moderate	40,256
Georgetown	52	Moderate	42,000
Wilton	56	Moderate	42,060

ZIP Codes in Norwalk

Norwalk covers 11 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 Norwalk?

Yes — Norwalk's average AQI is 49 (Good). Air pollution poses little or no risk for the general population.

How many unhealthy air days does Norwalk have?

Norwalk 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 Norwalk?

The average Air Quality Index (AQI) in Norwalk is 49, categorized as Good. 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 Norwalk?

Norwalk has a wildfire risk score of 11 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 Norwalk?

Norwalk has a mold risk score of 48 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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