Aspen, Colorado Air Quality
Aspen has a median AQI of 21, earning an air quality grade of A+ — excellent air quality that ranks better than 94% of US cities. Air quality has been trending worse over the past decade, a concern for local residents and health officials. Particulate matter (PM2.5) is the primary concern, often linked to vehicle traffic, industrial activity, and wildfire smoke. In 2025, Aspen recorded 250 good air quality days (92% of monitored days) and 1 unhealthy days.
Population: 6,756 • County: Pitkin
Current AQI
Quick Facts
| Current AQI | 21 — Good |
| Air Quality Grade | A+ |
| Median AQI (2025) | 21 |
| vs. U.S. Cities | Better than 94% |
| Primary Pollutant | PM2.5 |
| Unhealthy Days/Year | 1 |
| 10-Year Trend | ↓ Worsening |
| Data Source | EPA AQS (historical) · AirNow (live) |
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 90 Days
Current Pollutant Levels
Real-time data from EPA AirNow
Local Air Quality Context
Air quality data for Aspen is sourced from the Yellow Brick Building monitoring area, located approximately 1 miles from city center. This EPA-certified station continuously tracks particulate matter (PM2.5), the primary driver of air quality alerts in this area.
Wildfire smoke is a significant factor in Aspen's air quality, with regional fires capable of pushing AQI from Good to Unhealthy within hours during fire season (typically July through October). On smoke-impacted days, staying indoors with windows closed and running an air purifier with a HEPA filter is the most effective protection.
AQI Trend (10 Years)
Air Quality Days by Year
Aspen Median AQI by Year
Annual EPA air quality data for Aspen — median AQI, day-category breakdown, and primary pollutant per year.
| Year | Median AQI | Good Days | Unhealthy Days | Max AQI | Primary Pollutant |
|---|---|---|---|---|---|
| 2025 | 21 | 250 | 1 | 154 | PM2.5 |
| 2024 | 19 | 246 | — | 76 | PM2.5 |
| 2023 | 13 | 120 | — | 51 | PM10 |
| 2022 | 14 | 118 | — | 72 | PM10 |
| 2021 | 14 | 115 | — | 90 | PM10 |
| 2020 | 12 | 116 | — | 72 | PM10 |
| 2019 | 11 | 121 | — | 46 | PM10 |
| 2018 | 15 | 120 | — | 53 | PM10 |
| 2017 | 14 | 123 | — | 48 | PM10 |
| 2016 | 12 | 122 | — | 44 | PM10 |
Source: EPA Air Quality System (AQS) annual summaries. "Unhealthy Days" includes Unhealthy for Sensitive Groups, Unhealthy, Very Unhealthy, and Hazardous categories.
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 Aspen Air Quality
What is the air quality in Aspen today?
The current AQI in Aspen is 21, rated "Good". Air quality is good — outdoor activity is safe for everyone today. Air quality is satisfactory, and air pollution poses little or no risk.
Is air quality in Aspen getting better or worse?
Air quality in Aspen has been worsening. The median AQI has risen 9 points (from 12 in 2016 to 21 in 2025), a concern for local health officials.
What is the most common air pollutant in Aspen?
PM2.5 is the primary air pollutant in Aspen, responsible for 234 days (86% of monitored days) in 2025. Particulate matter originates from vehicle exhaust, wildfires, construction, and industrial activity.
How many unhealthy air days does Aspen have per year?
In 2025, Aspen recorded 92% good air quality days (250 days) out of 273 monitored days. There were 0 Unhealthy for Sensitive Groups days and 1 Unhealthy days (AQI above 100). The highest single-day AQI recorded was 154.
What air quality grade does Aspen receive?
Aspen receives an air quality grade of A+, placing it better than 94% of US cities. This is based on a median AQI of 21 in 2025, with 250 good air quality days. The EPA monitors air quality in this area continuously using certified monitoring stations.
Air Quality Grade
Better than 94% of US cities
Nearby Cities
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National Rankings
See how Aspen compares to every other US city by air quality.
Best Air Quality Cities →All city rankingsRecommended Air Purifiers for Aspen
Aspen faces elevated PM2.5 from wildfire smoke in addition to year-round traffic and industrial sources. We prioritize True HEPA units with high smoke CADR — essential for rapid air cleaning during smoke events.
Blueair Blue Pure 211+
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Other Great Options
Molekule Air Pro
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