AIR QUALITY MT

Air Quality in Stevensville, MT: Good (20 AQI)

AQI 20 · Good · PM2.5 · Updated 2026-05-03

Stevensville'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. Stevensville's average AQI of 20 falls in the "Good" 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 Stevensville

AQI varies across Stevensville's 1 ZIP codes based on proximity to pollution sources and local geography.

ZIP Code	AQI	Category	Wildfire	Mold
59870	20	Good	51	30	View report →

Air Quality Overview

Stevensville, Montana has good air quality with an average AQI of 20. 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 Stevensville

AQI varies across Stevensville's 1 ZIP codes based on proximity to pollution sources, traffic patterns, and local geography:

ZIP Code	AQI	Category	Wildfire Risk	Mold Score
59870	20	Good	51	30

Wildfire Smoke Risk

Stevensville has an elevated wildfire smoke risk with an average smoke risk score of 51 (scale 0-100). There have been 82 fires recorded within 100 km of city ZIP codes.

Metric	Value
Avg. smoke risk score	51
Max smoke risk score	51
Fires within 100 km	82
High-risk ZIP codes	1

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

Stevensville has an average mold risk score of 30 out of 100.

Factor	Value
Mold risk score	30/100
Average humidity	54% 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 good air quality (AQI 20), Stevensville 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

Stevensville vs. Nearby Montana Cities

How Stevensville's air quality compares to nearby cities:

City	AQI	Category	Population
Stevensville	20	Good	2,529
Troy	9	Good	2,508
Condon	18	Good	2,483
Eureka	N/A	N/A	2,625

ZIP Codes in Stevensville

Stevensville covers 1 ZIP code. 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 Stevensville?

Yes — Stevensville's average AQI is 20 (Good). Air pollution poses little or no risk for the general population.

How many unhealthy air days does Stevensville have?

Stevensville 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 Stevensville?

The average Air Quality Index (AQI) in Stevensville is 20, 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 Stevensville?

Stevensville has a wildfire risk score of 51 out of 100. Moderate wildfire risk means smoke events are possible. Having a HEPA air purifier available is recommended.

Is mold a concern in Stevensville?

Stevensville has a mold risk score of 30 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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