Hamilton, Montana Air Quality
Hamilton has a median AQI of 19, earning an air quality grade of A+ — excellent air quality that ranks better than 95% 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, Hamilton recorded 142 good air quality days (82% of monitored days).
Population: 5,101 • County: Ravalli
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Quick Facts
| Current AQI | 9 — Good |
| Air Quality Grade | A+ |
| Median AQI (2025) | 19 |
| vs. U.S. Cities | Better than 95% |
| 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 Hamilton Air Quality
What is the air quality in Hamilton today?
The current AQI in Hamilton is 9, which is rated "Good". Air quality is satisfactory, and air pollution poses little or no risk.
Is air quality in Hamilton getting better or worse?
Air quality in Hamilton has been improving over the past decade. The median AQI dropped from 34 in 2016 to 19 in 2025.
What is the most common air pollutant in Hamilton?
PM2.5 is the primary air pollutant in Hamilton, 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 Hamilton have per year?
In 2025, Hamilton had 0 days when air quality was unhealthy or unhealthy for sensitive groups (AQI above 100). There were 142 good days and 32 moderate days out of 174 days monitored.
What air quality grade does Hamilton receive?
Hamilton receives an air quality grade of A+, placing it better than 95% of US cities. This grade is based on a median AQI of 19 for 2025, derived from EPA monitoring data.
Air Quality Grade
Better than 95% of US cities
Nearby Cities
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National Rankings
See how Hamilton compares to every other US city by air quality.
Best Air Quality Cities →All city rankingsRecommended Air Purifiers for Hamilton
Based on your area's air quality (median AQI: 19), we recommend these air purifiers to help protect your health indoors.
RabbitAir MinusA2
Stylish wall-mountable design with customizable artwork panels.
- ✓Adequate for room size
- ✓Recommended for your air quality
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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.
Not sure which air purifier is right for you?
Learn more about different types of air purifiers and how to choose the best one for your needs.
Read our complete buying guide →