Air quality observations and historical context for Denver, CO
Historical perspective
Annual PM2.5 concentrations · µg/m³
| Year | PM2.5 |
|---|---|
| 2019 | 7.7 |
| 2020 | 8.8 |
| 2021 | 9.0 |
| 2022 | 6.5 |
| 2023 | 7.4 |
| 2024 | 6.6 |
Available history: 2019–2024. Historical scores are distinct from current AQI and do not describe today’s conditions.
Sources and scoring method ↗Local context
Start with the live AQI and forecast modules for Denver, then use the indoor action guidance below to decide whether to open windows, run a HEPA purifier, or stay inside during smoke and traffic-driven pollution.
Real-time pollutants resolved via none
Live air quality data is currently unavailable for this specific location. You can check nearby cities below for representative regional readings.
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Denver is treated as a major metro in CO, so the most useful signal is the long-term pollution baseline rather than a single live AQI reading. Annual PM2.5 averages 6.6 ug/m3, with roughly 0 unhealthy-air days per year, and the multi-year trend is improving. Its Clean Air Score is 79.7 (grade B), which helps compare Denver with other CO cities. In Denver, historical EPA observations show that pollution levels typically peak in October (averaging an index of 48), while the cleanest air conditions occur in May (averaging 22). With an extreme events rating of 100/100, Denver exhibits resilient atmospheric ventilation with fewer multi-day smoke outliers. This report uses direct city-level monitor coverage where available, so the trend is tied closely to conditions in Denver.
Autumn (Wildfire smoke drift & air stagnation)
Historically lowest pollution baseline
Fine particulate matter (PM2.5) in Denver is monitored for health safety. Long-term exposure to pollutants can lead to respiratory issues, making daily checks essential for active residents in CO.
These destinations have significantly higher historical Clean Air Scores than Denver (Score: 79.7).
Denver air quality can swing with wildfire smoke and winter inversions, so the indoor guidance below helps you decide when to filter or ventilate.
Get custom room-by-room HEPA purifier sizing, seasonal PM2.5 trends, and local home sealing recommendations.
Usually safe to open windows for fresh air.
Air purifier is optional for most households.
Normal indoor and outdoor activity is fine.
Ventilate selectively; sensitive groups should watch symptoms.
Run HEPA filtration on low if pollen, smoke smell, or traffic exhaust is noticeable.
Most people can continue normal activity; sensitive groups should keep an eye on AQI.
Keep windows closed so outdoor PM2.5 does not build indoors.
Run HEPA filtration in bedrooms and main living spaces.
Children, older adults, and people with asthma should reduce outdoor exertion.
Keep windows and doors sealed as much as practical.
Run filtration continuously; use the highest comfortable fan setting.
Stay indoors when possible and consider an N95 if you must go outside.
Given Denver's air quality profile and peak pollution season in October, maintaining certified HEPA filtration indoors is an effective defense against fine particulate matter.
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In areas with elevated particulate or seasonal stagnation, basic ionizers or thin sponge filters fail to clear indoor air. Review verified physical capture technologies before investing in home equipment.
Track outdoor smoke plumes via satellite and local AQI. Use an indoor laser PM2.5 monitor to verify that your clean room maintains particulate levels below 10 µg/m³.
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Most people can continue outdoor activities normally. Keep an eye on changing conditions.
Children and elderly should reduce prolonged or heavy outdoor exertion if AQI rises above 50.
Explore available hourly data before planning outdoor time in Denver.
Atmospheric fine particulate matter (PM2.5) and municipal drinking water contaminants represent the two primary involuntary daily exposures in any household. While HEPA filtration purifies indoor air, municipal tap water often contains invisible halogenated byproducts, heavy metals, or PFAS forever chemicals.
Denver holds a historical Clean Air Score of 79.7/100. High PM2.5 requires True HEPA (H13) physical media filters without electronic ozone generation.
Municipal utility compliance focuses on legal limits, not health guidelines. Verified solid-carbon or Reverse Osmosis filters target lead, chlorine byproducts, and micropollutants.
See how Denver’s pollution baselines and seasonal patterns compare side-by-side.
Current air quality in Denver is being monitored. Based on historical data, Denver has a clean air score of 79.7. For real-time updates, check the live monitoring panel on this page.
According to multi-year EPA observations, air pollution in Denver historically peaks during October (Autumn (Wildfire smoke drift & air stagnation)). The cleanest air window typically occurs in May.
Monitor real-time hourly spikes and verify indoor HEPA filtration during seasonal transitions. Maintaining certified indoor HEPA filtration is an effective way to minimize personal exposure.
An AQI (Air Quality Index) above 100 is considered unhealthy for sensitive groups, while levels above 150 are unhealthy for everyone. Levels above 300 are hazardous.
If the AQI in Denver is above 150, an N95 mask is recommended for outdoor activities to filter out fine particulate matter (PM2.5).
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