Median AQI
70
Moderate
New Mexico · County air quality · 2025
Dona Ana County, New Mexico
Median AQI 70 (Moderate). 19.4% of monitored days rated Good, direct from EPA Air Quality System stations.
- 70
- Median AQI
- 19.4%
- Good-air days
- 22
- Unhealthy days
- 1%
- Cleaner than US counties
The verdict
According to EPA Air Quality System monitoring data, Dona Ana County's air is moderate on balance, among the most polluted counties nationally, a median AQI of 70 with 19.4% of 273 monitored days in the Good band, driven mainly by Ozone.
- 70
- median AQI · Moderate
- 19.4%
- days rated Good
- Ozone
- main pollutant
- 1%
- cleaner than US counties
22 days reached Unhealthy or worse; the worst single reading hit AQI 528 - a reading beyond the EPA’s standard 0–500 AQI scale, reflecting an extreme wildfire-smoke event or a transient monitor anomaly.
Data updated July 2026
- Good · 53 d · 19.4%
- Moderate · 170 d · 62.3%
- USG · 28 d · 10.3%
- Unhealthy · 7 d · 2.6%
- Very Unhealthy · 5 d · 1.8%
- Hazardous · 10 d · 3.7%
How did Dona Ana County's air break down in 2025?
Across 273 monitored days, 53 fell in the Good band (AQI 0–50) and 22 reached Unhealthy or worse. The worst single day peaked at AQI 528 (Hazardous) - a reading beyond the EPA’s standard 0–500 AQI scale, reflecting an extreme wildfire-smoke event or a transient monitor anomaly.
EPA AQS →Air quality data from EPA Air Quality System (2025). 273 days monitored. Median AQI: 70 (Moderate).
Insights: Dona Ana County, New Mexico. EPA monitors recorded a median Air Quality Index of 70 across 273 measured days in 2025, earning a Moderate classification and a Very Poor health grade. Of those days, 53 (19%) fell in the Good band (AQI 0–50), 170 (62%) registered Moderate readings, and 28 (10%) reached Unhealthy for Sensitive Groups. The 90th-percentile AQI settled at 130, while the worst single-day peak hit 528 (Hazardous). Residents averaged about 5.8 clean-air days per 30-day window during the monitoring year.
The full pollutant mix ranks as Ozone (117 days), PM2.5 (87 days), PM10 (68 days), NO2 (1 days). Across the 2020–2025 trend window, good days shifted by -91 and the median AQI moved +16 points, placing the multi-year trajectory at worsening. Residents and visitors experienced 22 unhealthy-or-worse days combined, periods when the EPA recommends sensitive groups limit prolonged outdoor exertion. Nearby counties show comparable readings: Bernalillo (23.7% good, AQI 59); Catron (100.0% good, AQI 8); Chaves (94.4% good, AQI 16); Eddy (46.9% good, AQI 51); Lea (61.5% good, AQI 47); Lincoln (89.5% good, AQI 11).
Air Quality Summary
Good Days
19.4%
53 of 273 monitored days
-55.6pp vs 75% target
Max AQI Recorded
528
Hazardous
Health Grade
Very Poor
90th-pct AQI 130
Dona Ana County, Good days share 19.4%
National avg
Share of monitored days at AQI 0-50 (Good band).
Dona Ana County, Unhealthy-or-worse share 8.1%
National avg
Share of monitored days above AQI 150 (Unhealthy or worse). Bar maxes at 10% (worst-county ceiling).
AQI Day Breakdown (2025)
Distribution of 273 monitored days across EPA AQI categories.
Good
53
19%
Moderate
170
62%
USG
28
10%
Unhealthy
7
3%
Very Unhealthy
5
2%
Hazardous
10
4%
Pollutant Breakdown
Days where each pollutant was the primary driver of AQI readings in Dona Ana County.
- Ozone · 117 days · 42.9%
- PM2.5 · 87 days · 31.9%
- PM10 · 68 days · 24.9%
- NO₂ · 1 days · 0.4%
Health Impact Assessment
Very Poor
Dona Ana County's air quality is rated Very Poor based on 19.4% good air days. There were 22 unhealthy days in 2025 when outdoor activity should be limited.
Air quality posed significant health risk in 2025. Sensitive groups, including people with asthma, COPD, cardiovascular conditions, children, pregnant women, and adults over 65, should monitor AirNow.gov alerts and limit outdoor activity on Unhealthy (AQI 151+) and Very Unhealthy (201+) days. Peak readings reached AQI 528, beyond EPA's standard 0-500 scale, indicating an extreme event.
Sensitive group advisory
People with asthma, COPD, heart disease, children, pregnant women, and adults 65+ should follow EPA AQI alerts daily and limit outdoor exertion when AQI exceeds 100. Real-time conditions: airnow.gov.
Note: EPA's standard AQI scale caps at 500 (Hazardous category 301-500). The 528 peak reading represents an extreme event, typically wildfire smoke, extrapolated beyond the index's design range. See EPA wildfire smoke guidance.
The dominant pollutant is Ozone, driving AQI on 117 of 273 monitored days.
5-Year Air Quality Trend
Air quality is worsening in Dona Ana County. Best year: 2023 (162 good days).
| Year | Good | Moderate | USG | Unhealthy | Median AQI | Max AQI |
|---|---|---|---|---|---|---|
| 2020 | 144 | 201 | 15 | 3 | 54 | 389 |
| 2021 | 126 | 208 | 20 | 8 | 56 | 683 |
| 2022 | 157 | 179 | 24 | 1 | 53 | 367 |
| 2023 | 162 | 189 | 11 | 3 | 52 | 196 |
| 2024 | 97 | 237 | 19 | 6 | 62 | 692 |
| 2025 | 53 | 170 | 28 | 7 | 70 | 528 |
How does Dona Ana County compare?
How Dona Ana County compares
Good-day share worse than US avg
Dona Ana County 19.4%
Bernalillo County, New Mexico 23.7%
US average 76.5%
Median AQI worse than US avg
Dona Ana County 70
Bernalillo County, New Mexico 59
US average 38
Unhealthy days / yr worse than US avg
Dona Ana County 22
Bernalillo County, New Mexico 3
US average 0
Other Counties in New Mexico
Air quality comparison for nearby counties in New Mexico.
Counties with Similar Air Quality
Counties across the US with a similar median AQI to Dona Ana County.
Maricopa County, Arizona
AQI 71 · 16.4% good
El Paso County, Texas
AQI 74 · 12.7% good
Pinal County, Arizona
AQI 66 · 24.6% good
Clark County, Nevada
AQI 64 · 25.6% good
Imperial County, California
AQI 64 · 27.4% good
Harris County, Texas
AQI 63 · 8.8% good
What Dona Ana County's air means for you
On most days the air here is fine, but Ozone drives 22 unhealthy-or-worse days a year that sensitive groups should plan around.
- Sensitive groups (asthma, heart conditions, children, older adults) should check the AQI on high-Ozone days, the guide explains what a median of 70 means for exposure. Health guidance
- See how Dona Ana County ranks against every monitored U.S. county on Good-day share. County rankings
- Compare Dona Ana County with its New Mexico neighbours before drawing a conclusion about the region. All of New Mexico
Based on 273 EPA-monitored days in 2025; figures reflect only days the monitors reported. Source: EPA Air Quality System annual summaries.
More Air Quality Data
Air Quality Guides
Frequently Asked Questions
What is the air quality in Dona Ana County, New Mexico? ▼
Dona Ana County has a median Air Quality Index (AQI) of 70, rated "Moderate." 19.4% of monitored days (53 out of 273) had good air quality in 2025.
What is the main pollutant in Dona Ana County? ▼
The primary pollutant in Dona Ana County is Ozone (O3), which was the main AQI driver on 117 days (43% of monitored days). Can trigger asthma, reduce lung function, and cause chest pain.
How many unhealthy air days does Dona Ana County have? ▼
In 2025, Dona Ana County recorded 22 unhealthy air days (7 Unhealthy, 5 Very Unhealthy, 10 Hazardous). The maximum AQI reached 528 - a reading beyond the EPA’s standard 0–500 AQI scale, reflecting an extreme wildfire-smoke event or a transient monitor anomaly.
Is the air quality in Dona Ana County getting better or worse? ▼
Air quality in Dona Ana County is worsening based on 5-year trends (2020-2025). Best year: 2023 with 162 good days. Worst year: 2025 with 53 good days.
What does AQI 70 mean for health? ▼
Dona Ana County's median AQI of 70 falls in the "Moderate" category. See the <a href="/guides/understanding-aqi" class="underline">AQI category guide</a> for what each range means for health.
How does Dona Ana County compare to other counties in New Mexico? ▼
Dona Ana County has 19.4% good air days. Nearby counties in New Mexico: Bernalillo (23.7% good), Catron (100.0% good), Chaves (94.4% good), Eddy (46.9% good), Lea (61.5% good), Lincoln (89.5% good).
What is the 90th percentile AQI in Dona Ana County? ▼
The 90th percentile AQI for Dona Ana County is 130, meaning 90% of monitored days had an AQI at or below this level. The maximum AQI recorded was 528 - a reading beyond the EPA’s standard 0–500 AQI scale, reflecting an extreme wildfire-smoke event or a transient monitor anomaly (Hazardous).
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.
Every figure on PlainAir 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.