Colorado · County air quality · 2025
La Plata County, Colorado
Median AQI 48 (Good). 60.8% of monitored days rated Good, direct from EPA Air Quality System stations.
- 48
- Median AQI
- 60.8%
- Good-air days
- 0
- Unhealthy days
- 16%
- Cleaner than US counties
La Plata County's 2025 annual median AQI is 48 (Good), with 60.8% Good days
According to the U.S. EPA Air Quality System, La Plata County, Colorado posted a 2025 median AQI of 48 (Good) across 365 monitored days, with 60.8% rated Good and 0 unhealthy or worse. This is an annual comparison, not today's advisory.
Data source EPA Air Quality System (AQS)
- Cleaner than US
- La Plata County's 60.8% Good-day share places it cleaner than 16% of US counties in 2025.
- Closest median-AQI peer
- Adair County (55.8% Good, median AQI 48) is the closest nationwide median-AQI peer to La Plata County.
- 2020–2025 trend
- La Plata County's floor-qualifying Good-day share is worsening from 2020 to 2025 (74.6% → 60.8%).
- Median AQI
- Median AQI: 48
According to the 2025 EPA AQS county release on PlainAirData, La Plata County, Colorado ranks #843 of 951 by median AQI (48) and #796 by good-day share (60.8%). Ponce County, Puerto Rico is #1 of 951 by median AQI (3, 91.4% Good days) at good-day-share #159 ≠ largest of 7 at 100.0% Good days #1 by good-day share (100.0%, median AQI 9) at median-AQI #7.
Annual release change
What changed in the 2025 EPA annual release
- La Plata County's peak single-day AQI fell from 240 to 112 between the 2024 and 2025 EPA annual releases, a change of -128 points.
- La Plata County's Good-day share fell from 65.8% to 60.8% between the 2024 and 2025 EPA annual releases, a change of -5.0 percentage points.
Data updated August 2026
- Good · 222 d · 60.8%
- Moderate · 141 d · 38.6%
- USG · 2 d · 0.5%
How did La Plata County's air break down in 2025?
Across 365 monitored days, 222 fell in the Good band (AQI 0–50) and 0 reached Unhealthy or worse. The worst single day peaked at AQI 112 (USG).
EPA AQS →Share of monitored days at AQI 0-50 (Good band).
Share of monitored days above AQI 150 (Unhealthy or worse). Bar maxes at 10% (worst-county ceiling).
Where La Plata County sits nationally
COUNT-derived placement among 951 US counties with at least 100 monitored days in 2025. La Plata County's Good-day share is 60.8% - cleaner than 16% of that comparison set.
La Plata County Good-day share vs. every US county
Share of monitored days in the Good band (AQI 0–50) - EPA AQS annual release
60.8% 16th percentile higher than 16% of 951 US counties
Each bar is a band; taller bars hold more US counties. The dashed line + filled bar mark this entry. Hover or tap any bar for its full count, share, and where it sits relative to this entry.
Source U.S. Environmental Protection Agency, Air Quality System (AQS) · 2025
Pollutant Breakdown
Days where each pollutant was the primary driver of AQI readings in La Plata County.
- Ozone · 349 days · 95.6%
- PM2.5 · 16 days · 4.4%
2024 daily-monitor rhythm in La Plata County
Month-by-month median AQI from EPA day-level county monitors (366 reported days in 2024). May posted the highest typical readings (median AQI 67, peak 97); Dec was cleanest at median 38. Summer months (Jun–Aug) averaged median AQI 53 vs 40 in Dec–Feb. 1 day crossed Unhealthy (AQI >150) at least once that year.
Five-year seasonal record
EPA day-level county files · 2020–20241,826 daily readings show a recurring local pattern: May has the highest matched-month median AQI (61), while Dec is lowest (37). Each cell is that month’s median daily AQI, not a current-air forecast.
Lower AQI is better. The colors summarize EPA AQI bands; gaps mean the county had no day-level record for that month.
Health Impact Assessment
La Plata County's air quality is rated Moderate based on 60.8% good air days. No unhealthy air days were recorded in 2025.
Air quality was acceptable on 60.8% of monitored days in 2025, with a median AQI of 48. Unusually sensitive people can check real-time conditions at AirNow.gov during high-pollution events.
The dominant pollutant is Ozone, driving AQI on 349 of 365 monitored days.
5-Year Air Quality Trend
Air quality is worsening in La Plata County. Highest Good-day share: 2020 (74.6%, 273 of 366 monitored days).
| Year | Good | Moderate | USG | Unhealthy | Median AQI | Max AQI |
|---|---|---|---|---|---|---|
| 2020 | 273 | 91 | 2 | 0 | 45 | 133 |
| 2021 | 239 | 121 | 4 | 0 | 47 | 140 |
| 2022 | 266 | 98 | 1 | 0 | 46 | 108 |
| 2023 | 237 | 123 | 2 | 2 | 46 | 211 |
| 2024 | 241 | 123 | 1 | 0 | 46 | 240 |
| 2025 | 222 | 141 | 2 | 0 | 48 | 112 |
How does La Plata County compare?
How La Plata County compares
Data Sources
Primary Source: U.S. Environmental Protection Agency (EPA), Air Quality System (AQS), Annual AQI by County dataset, 2020–2025 (aqs.epa.gov). For current conditions (not shown here — this page is historical annual data), see EPA AirNow (airnow.gov). See our methodology for how AQI, median, and coverage figures are computed.
Informational only, not professional advice. Data from EPA AQS. See our disclaimer. Spotted a figure that looks wrong? Report a correction.
Source: U.S. EPA Air Quality System (AQS) Annual AQI by county summary files for La Plata County, Colorado · 2020–2025
Download this county's annual AQI row as CSV , with the same EPA fields and denominator shown on this page.
Every figure on PlainAirData is rendered directly from EPA AQS air-quality monitoring data, no number is typed in by an editor. This page draws directly on EPA AQS air-quality monitoring data, no figure is typed in by an editor. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error.