Aurora, CO Air Quality in 2019
In 2019, Aurora's air quality (Denver-Aurora-Lakewood, CO area) had a median daily AQI of 64 (Moderate) across 365 monitored days. 24 days (6.6%) reached Unhealthy for Sensitive Groups or worse, 51 were Good, and the year's peak AQI was 154 (Unhealthy). Ground-level ozone set the daily AQI on 215 of those days. The cleanest month of 2019 was October (median AQI 54, 0 days above 100) and the worst was July (median 80, 9 days above 100, peak 133).
- Good: 14.0%
- Moderate: 79.5%
- Unhealthy for Sensitive Groups: 6.0%
- Unhealthy or worse: 0.5%
Reduce Indoor Ozone in Aurora
Today's main pollutant in Aurora is ground-level ozone (AQI 48). Important: standard HEPA filters do NOT remove ozone — only a purifier with a substantial activated-carbon bed adsorbs it. The biggest wins are cutting indoor sources (gas appliances, certain "ionizer" purifiers) and ventilating when outdoor ozone is low (early morning). A high-carbon unit helps with the gases and VOCs that linger indoors.
Recommended: Levoit Core 300 — True HEPA + activated carbon · CADR ~141 CFM · rooms up to 219 sq ft
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How was Aurora's air quality in 2019?
Moderate on a typical day: median AQI 64, with 24 days above AQI 100 out of 365 monitored — the 2nd cleanest of 7 years on record for the area.
- ✓Peak AQI in 2019: 154 (Unhealthy).
- ✓Ground-level ozone was the main pollutant on 215 days.
- ✓Cleanest month: October; worst: July.
Frequently asked questions
What was the average AQI in Aurora in 2019?▾
EPA's Air Quality System puts Aurora's (Denver-Aurora-Lakewood, CO) median daily AQI for 2019 at 64, which is Moderate. 24 days were Unhealthy for Sensitive Groups or worse and the year's highest AQI was 154.
Which month had the worst air quality in Aurora in 2019?▾
The cleanest month of 2019 was October (median AQI 54, 0 days above 100) and the worst was July (median 80, 9 days above 100, peak 133).
Was 2019 a good or bad year for Aurora's air?▾
Among the 7 years EPA has published for the area (2019–2025), 2019 ranks 2nd cleanest by days above AQI 100. 2019's median of 64 is in line with the area's typical annual median of 64.
Aurora month by month in 2019
Aurora air quality month by month, 2019 (Denver-Aurora-Lakewood, CO, EPA AQS daily AQI)
| Month | Days monitored | Median AQI | Days above 100 | Peak AQI | Main pollutant |
|---|---|---|---|---|---|
| January | 31 | 58 | 0 | 76 | PM2.5 |
| February | 28 | 63 | 0 | 99 | PM2.5 |
| March | 31 | 64 | 1 | 153 | O3 |
| April | 30 | 63 | 0 | 97 | O3 |
| May | 31 | 77 | 2 | 101 | O3 |
| June | 30 | 74 | 3 | 115 | O3 |
| Julyworst | 31 | 80 | 9 | 133 | O3 |
| August | 31 | 87 | 8 | 154 | O3 |
| September | 30 | 64 | 1 | 112 | O3 |
| Octobercleanest | 31 | 54 | 0 | 87 | O3 |
| November | 30 | 57 | 0 | 91 | PM2.5 |
| December | 31 | 61 | 0 | 83 | PM2.5 |
How 2019 compares
Among the 7 years EPA has published for the area (2019–2025), 2019 ranks 2nd cleanest by days above AQI 100.
2019's median of 64 is in line with the area's typical annual median of 64.
Activity-specific thresholds: running, cycling, kids' sports.
Right now in Aurora
The latest EPA AirNow observation puts Aurora's AQI at 48 (O3). The figures above are multi-year annual statistics, not today's reading.
View current Aurora air quality →Source: EPA Air Quality System (AQS) pre-generated Daily AQI by CBSA files — daily AQI by CBSA (Denver-Aurora-Lakewood, CO), 2019–2025. Daily AQI per CBSA is the highest AQI reported by any monitor in the area that day; the defining parameter is the pollutant that set it. Month and season statistics pool every such day in the period across all years listed. Retrieved 2026-09-09.