Bad Air Days in Dona Ana County, New Mexico: 28 a Year
28 bad air days a year
Among the worst tenth of monitored US counties. Ranked 20 of 996 monitored counties, where 1 is worst.
What makes them bad: a mix of particles and ozone (48% particle days).
When the bad days come in Dona Ana
- J
- F
- M
- A
- M
- J
- J
- A
- S
- O
- N
- D
Most bad days here fall in July and August and June and May. Averaged over 2016 to 2025.
Is a purifier worth it here?
- Particles (wildfire smoke, dust) cause enough bad days here to matter. A HEPA purifier sized to your bedroom removes them; run it with windows shut on bad days.
- Upgrade the furnace or AC filter to MERV 13 so the whole house is filtered, not just one room.
- Ozone drives many bad days here. Purifiers and filters do not remove ozone, so do not buy one for that. Ozone peaks on hot afternoons: exercise outside in the morning.
- Sign up for EnviroFlash ozone alerts for this area during the worst months.
The worst days on file
In 2000 to 2009 this county averaged 37 bad days a year; in 2016 to 2025, 28. The air has improved. The worst recent year was 2025, with 48 bad days on 365 monitored days.
| Date | AQI | Main pollutant |
|---|---|---|
| 2024-03-24 | 692 | PM10 |
| 2021-03-16 | 683 | PM10 |
| 2019-03-08 | 645 | PM10 |
| 2024-03-15 | 643 | PM10 |
| 2017-03-23 | 630 | PM10 |
The air on a normal day
Across 3,653 monitored days from 2016 to 2025, the air in Dona Ana County rated Good on 35% of them, less often than the 72% typical of monitored counties, and Moderate on 57%. The median day sat at AQI 56; one day in ten went above 95.
The pollutant setting the AQI on an ordinary day here:
- ozone56%2,037 days
- fine particles (PM2.5)24%868 days
- coarse dust (PM10)19%702 days
- nitrogen dioxide1%46 days
Every recent year on file
| Year | Days monitored | Good | Moderate | Over 100 | Over 150 | Median AQI | Highest AQI |
|---|---|---|---|---|---|---|---|
| 2025* | 365 | 100 | 217 | 48 | 21 | 61 | 528 |
| 2024 | 366 | 97 | 237 | 32 | 13 | 62 | 692 |
| 2023 | 365 | 162 | 189 | 14 | 3 | 52 | 196 |
| 2022 | 365 | 157 | 179 | 29 | 5 | 53 | 367 |
| 2021 | 365 | 126 | 208 | 31 | 11 | 56 | 683 |
| 2020 | 366 | 144 | 201 | 21 | 6 | 54 | 389 |
| 2019 | 365 | 156 | 185 | 24 | 7 | 54 | 645 |
| 2018 | 365 | 121 | 212 | 32 | 4 | 58 | 187 |
| 2017 | 365 | 116 | 215 | 34 | 7 | 58 | 630 |
| 2016 | 366 | 111 | 240 | 15 | 3 | 56 | 594 |
| 2015 | 365 | 109 | 244 | 12 | 1 | 55 | 157 |
| 2014 | 365 | 179 | 166 | 20 | 7 | 51 | 450 |
| 2013 | 365 | 149 | 162 | 54 | 15 | 58 | 453 |
| 2012 | 366 | 136 | 199 | 31 | 8 | 54 | 1762 |
| 2011 | 365 | 116 | 219 | 30 | 8 | 59 | 818 |
| 2010 | 365 | 120 | 233 | 12 | 5 | 56 | 690 |
*2025 may be a partial year in EPA's file.
Nearby counties on file
- Eddy County19/yr
- Bernalillo County15/yr
- San Juan County6/yr
- Luna County5/yr
- Lea County4/yr
- Sandoval County2/yr
- Valencia County1/yr
- Rio Arriba County1/yr
How this is counted
A bad air day is a day the county's daily AQI from EPA AirData went above 100, the level where EPA tells children, older adults and people with asthma or heart disease to cut back outdoors. Monitors do not run every day, so yearly counts are scaled to 365 days. This is the record, not today's air: for that, check AirNow. More on the method in how the county numbers are made, on the AQI 100 line in what counts as a bad air day, and on why a purifier does not touch ozone in smoke vs ozone.