Hamilton City, California Air Quality
Hamilton City has a median AQI of 40, earning an air quality grade of A — excellent air quality that ranks better than 60% of US cities. Air quality has been improving steadily over the past decade, a positive sign for residents. Ground-level ozone is the primary concern, typically peaking on warm sunny days due to vehicle and industrial emissions. In 2025, Hamilton City recorded 170 good air quality days (80% of monitored days).
Population: 2,267 • County: Glenn
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Quick Facts
| Current AQI | 16 — Good |
| Air Quality Grade | A |
| Median AQI (2025) | 40 |
| vs. U.S. Cities | Better than 60% |
| Primary Pollutant | Ozone |
| 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 City Air Quality
What is the air quality in Hamilton City today?
The current AQI in Hamilton City is 16, which is rated "Good". Air quality is satisfactory, and air pollution poses little or no risk.
Is air quality in Hamilton City getting better or worse?
Air quality in Hamilton City has been improving over the past decade. The median AQI dropped from 48 in 2016 to 40 in 2025.
What is the most common air pollutant in Hamilton City?
Ozone is the primary air pollutant in Hamilton City, responsible for the most air quality-impacted days in 2025. Ground-level ozone forms when sunlight reacts with vehicle and industrial emissions on warm days.
How many unhealthy air days does Hamilton City have per year?
In 2025, Hamilton City had 0 days when air quality was unhealthy or unhealthy for sensitive groups (AQI above 100). There were 170 good days and 42 moderate days out of 212 days monitored.
What air quality grade does Hamilton City receive?
Hamilton City receives an air quality grade of A, placing it better than 60% of US cities. This grade is based on a median AQI of 40 for 2025, derived from EPA monitoring data.
Air Quality Grade
Better than 60% of US cities
Nearby Cities
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National Rankings
See how Hamilton City compares to every other US city by air quality.
Best Air Quality Cities →All city rankingsRecommended Air Purifiers for Hamilton City
Based on your area's air quality (median AQI: 40), 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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