Big Arm, Montana Air Quality
Big Arm has a median AQI of 4, earning an air quality grade of A+ — excellent air quality that ranks better than 100% of US cities. Air quality has been improving steadily over the past decade, a positive sign for residents. Particulate matter (PM2.5) is the primary concern, often linked to vehicle traffic, industrial activity, and wildfire smoke. In 2025, Big Arm recorded 20 good air quality days (100% of monitored days).
Population: 190 • County: Lake
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Quick Facts
| Current AQI | 29 — Good |
| Air Quality Grade | A+ |
| Median AQI (2025) | 4 |
| vs. U.S. Cities | Better than 100% |
| Primary Pollutant | PM2.5 |
| Unhealthy Days/Year | 0 |
| 10-Year Trend | ↑ Improving |
| Data Source | EPA AirNow |
Health Recommendation
Air quality is satisfactory, and air pollution poses little or no risk.
It's a great day to be active outside!
5-Day AQI Forecast
Last 30 Days
Current Pollutant Levels
Real-time data from EPA AirNow
AQI Trend (10 Years)
Air Quality Days by Year
2025 Air Quality Summary
Primary Pollutant Days (2025)
Days when each pollutant was the primary driver of AQI. Learn about pollutants →
Frequently Asked Questions About Big Arm Air Quality
What is the air quality in Big Arm today?
The current AQI in Big Arm is 29, which is rated "Good". Air quality is satisfactory, and air pollution poses little or no risk.
Is air quality in Big Arm getting better or worse?
Air quality in Big Arm has been improving over the past decade. The median AQI dropped from 8 in 2016 to 4 in 2025.
What is the most common air pollutant in Big Arm?
PM2.5 is the primary air pollutant in Big Arm, responsible for the most air quality-impacted days in 2025. Particulate matter can originate from vehicle exhaust, wildfires, and industrial emissions.
How many unhealthy air days does Big Arm have per year?
In 2025, Big Arm had 0 days when air quality was unhealthy or unhealthy for sensitive groups (AQI above 100). There were 20 good days and 0 moderate days out of 20 days monitored.
What air quality grade does Big Arm receive?
Big Arm receives an air quality grade of A+, placing it better than 100% of US cities. This grade is based on a median AQI of 4 for 2025, derived from EPA monitoring data.
Air Quality Grade
Better than 100% of US cities
Nearby Cities
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National Rankings
See how Big Arm compares to every other US city by air quality.
Best Air Quality Cities →All city rankingsRecommended Air Purifiers for Big Arm
Based on your area's air quality (median AQI: 4), we recommend these air purifiers to help protect your health indoors.
RabbitAir MinusA2
Stylish wall-mountable design with customizable artwork panels.
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Other Great Options
Molekule Air Pro
Commercial-grade with patented PECO technology for destroying pollutants.
Blueair Blue Pure 211+
High performance for large rooms with simple operation.
Dyson Pure Cool TP04
Premium all-in-one air purifier and fan with advanced features.
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Read our complete buying guide →