AIR QUALITY IA

Air Quality in Sioux City, IA: Good (40 AQI)

AQI 40 · Good · Ozone · Updated 2026-05-03

Sioux City'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

Unhealthy Days

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. Sioux City's average AQI of 40 falls in the "Good" range.

Air Quality Map: Sioux City, IA

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 Sioux City

AQI varies across Sioux City's 9 ZIP codes based on proximity to pollution sources and local geography.

ZIP Code	AQI	Category	Wildfire	Mold
51102	44	Good	13	38	View report →
51101	39	Good	13	55	View report →
51103	39	Good	13	67	View report →
51104	39	Good	13	61	View report →
51105	39	Good	13	55	View report →
51106	39	Good	13	52	View report →
51108	39	Good	13	52	View report →
51109	39	Good	13	55	View report →
51111	39	Good	13	46	View report →

Air Quality Overview

Sioux City, Iowa has good air quality with an average AQI of 40. 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 Sioux City

AQI varies across Sioux City's 9 ZIP codes based on proximity to pollution sources, traffic patterns, and local geography:

ZIP Code	AQI	Category	Wildfire Risk	Mold Score
51102	44	Good	13	38
51101	39	Good	13	55
51103	39	Good	13	67
51104	39	Good	13	61
51105	39	Good	13	55
51106	39	Good	13	52
51108	39	Good	13	52
51109	39	Good	13	55
51111	39	Good	13	46

Wildfire Smoke Risk

Sioux City has an elevated wildfire smoke risk with an average smoke risk score of 13 (scale 0-100).

Metric	Value
Avg. smoke risk score	13
Max smoke risk score	13
Fires within 100 km	0
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

Sioux City has an average mold risk score of 53 out of 100, with 5 ZIP codes in the high-risk category.

Factor	Value
Mold risk score	53/100
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 40), Sioux City 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

Sioux City vs. Nearby Iowa Cities

How Sioux City's air quality compares to nearby cities:

City	AQI	Category	Population
Sioux City	40	Good	85,824
Ankeny	76	Moderate	80,314
Ames	N/A	N/A	97,632
Iowa City	97	Moderate	98,352

ZIP Codes in Sioux City

Sioux City covers 9 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 Sioux City?

Yes — Sioux City's average AQI is 40 (Good). Air pollution poses little or no risk for the general population.

How many unhealthy air days does Sioux City have?

Sioux City experiences 1 unhealthy air quality day per year on average. During these days, everyone — not just sensitive groups — should reduce prolonged outdoor exertion.

What is the AQI in Sioux City?

The average Air Quality Index (AQI) in Sioux City is 40, categorized as Good. 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 Sioux City?

Sioux City has a wildfire risk score of 13 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 Sioux City?

Sioux City has a mold risk score of 53 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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