What Is the Air Quality in Custer, Oklahoma?
Custer, Oklahoma has an Air Quality Grade of A (excellent) with a 5-year median AQI of 14. The dominant pollutant is Coarse Particulate Matter (PM10), and air quality has been stable over the past decade.
Custer, Oklahoma Air Quality Snapshot
| Air Quality Grade | A80/100 |
| 5-Year Median AQI | 14 (Good) |
| Most Recent Median AQI (2019) | 14 (Good) |
| Dominant Pollutant | Coarse Particulate Matter (PM10) |
| 10-Year Trend | Stable (-0.10 AQI/yr) |
| Unhealthy Days (last 5 yr) | 0 |
| National Rank (cleanest = #1) | #29 of 1,020 (3th cleanest percentile) |
| Oklahoma Rank | #1 of 22 |
What Does the A Grade Mean?
Custer, Oklahoma earns an A — it is among the cleanest U.S. cities tracked by EPA monitoring, with median AQI averaging just 14 over the past five years. Days in the "Good" category dominate the calendar; air-quality alerts are rare.
Custer, Oklahoma's 5-year median AQI of 14 is 27 points below the national average of 41 — meaningfully cleaner than the typical U.S. metro tracked here. Within Oklahoma, Custer, Oklahoma runs cleaner than the state average of 42 — a positive signal that local conditions (terrain, wind patterns, emission sources) are working in residents' favor.
For context within Oklahoma: Muskogee, Oklahoma currently holds the state's cleanest grade (A, AQI 18), while Oklahoma, Oklahoma sits at the bottom (C, AQI 53).
What's in Custer, Oklahoma's Air?
The dominant pollutant in Custer, Oklahoma is Coarse Particulate Matter (PM10). Coarse particulate matter — particles up to 10 micrometers across — typically comes from dust, construction sites, agriculture, unpaved roads, and natural sources like windblown soil. PM10 is less hazardous than PM2.5 because the larger particles do not penetrate as deeply into the lungs, but high levels still aggravate asthma and irritate airways.
Days by Dominant Pollutant (2019)
| Pollutant | Days as Dominant | Share of Year |
|---|---|---|
| Coarse Particulate Matter (PM10) | 236 | 100% |
Is the Air Getting Better or Worse?
Air quality in Custer, Oklahoma has held roughly steady over the past decade, with year-to-year shifts in median AQI of less than half a point. That stability makes the city's long-run grade a reliable signal of what residents can expect day-to-day.
In 2015, Custer, Oklahoma posted a median AQI of 15. By 2019 that figure was 14 — a drop of 1 AQI points cleaner across 5 years of EPA records.
Year-by-Year AQI in Custer, Oklahoma
| Year | Median AQI | Good Days | Unhealthy Days | Dominant Pollutant |
|---|---|---|---|---|
| 2015 | 15 | 135 | 0 | PM10 |
| 2016 | 15 | 357 | 0 | PM10 |
| 2017 | 17 | 302 | 0 | PM10 |
| 2018 | 16 | 355 | 1 | PM10 |
| 2019 | 14 | 235 | 0 | PM10 |
Health Context for Custer, Oklahoma
Across the past five years, this area has logged just 0 days where AQI rose into the "Unhealthy for Sensitive Groups" range or worse — about 0 days per year, or roughly one every other month. That is a low count by national standards.
For most healthy adults, current air quality in this area does not require any change in behavior. People with severe asthma, COPD, or recent cardiac events should still keep an eye on daily AQI alerts, especially during wildfire season. PM10 is largely a near-source pollutant — staying upwind of busy roads, construction, and unpaved areas can substantially reduce exposure.
How This Grade Is Calculated
The AirHistory Air Quality Grade combines four signals: the 5-year median AQI (40% of the score), the 10-year trend direction (30%), the count of unhealthy days per year (20%), and the dominant pollutant type (10%). All four come directly from the EPA Air Quality System (AQS), which aggregates readings from federally certified monitors. Read the full methodology.
Custer, Oklahoma has an Air Quality Grade of A (excellent) with a 5-year median AQI of 14. The dominant pollutant is Coarse Particulate Matter (PM10), and air quality has been stable over the past decade.
This answer pulls from the EPA Air Quality System (AQS), the authoritative federal source for U.S. air quality and pollution monitoring. The headline number above is the direct answer; what follows is the additional context most readers need to use the answer for a real decision rather than just a fact lookup.
A practical caveat: the headline answer above reflects the most recent the EPA Air Quality System (AQS) vintage; underlying data is often revised for months after first publication, and the right reference for any specific decision is whichever vintage is current at the time of the decision. The as-of date is stamped on every page.
Source: EPA Outdoor Air Quality Data, 2026.