What Is the Air Quality in Cass, Nebraska?
Cass, Nebraska has an Air Quality Grade of A (excellent) with a 5-year median AQI of 16. The dominant pollutant is Coarse Particulate Matter (PM10), and air quality has been improving over the past decade.
Cass, Nebraska Air Quality Snapshot
| Air Quality Grade | A84/100 |
| 5-Year Median AQI | 16 (Good) |
| Most Recent Median AQI (2023) | 17 (Good) |
| Dominant Pollutant | Coarse Particulate Matter (PM10) |
| 10-Year Trend | Improving (-0.73 AQI/yr) |
| Unhealthy Days (last 5 yr) | 0 |
| National Rank (cleanest = #1) | #41 of 1,020 (4th cleanest percentile) |
| Nebraska Rank | #1 of 9 |
What Does the A Grade Mean?
Cass, Nebraska earns an A — it is among the cleanest U.S. cities tracked by EPA monitoring, with median AQI averaging just 16 over the past five years. Days in the "Good" category dominate the calendar; air-quality alerts are rare.
Cass, Nebraska's 5-year median AQI of 16 is 25 points below the national average of 41 — meaningfully cleaner than the typical U.S. metro tracked here. Within Nebraska, Cass, Nebraska runs cleaner than the state average of 30 — a positive signal that local conditions (terrain, wind patterns, emission sources) are working in residents' favor.
For context within Nebraska: Scotts Bluff, Nebraska currently holds the state's cleanest grade (B, AQI 24), while Knox, Nebraska sits at the bottom (C, AQI 37).
What's in Cass, Nebraska's Air?
The dominant pollutant in Cass, Nebraska 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 (2023)
| Pollutant | Days as Dominant | Share of Year |
|---|---|---|
| Coarse Particulate Matter (PM10) | 354 | 100% |
Is the Air Getting Better or Worse?
Air quality in Cass, Nebraska has been improving over the past decade, with median AQI dropping by roughly 0.7 points per year. That is consistent with the broader national pattern — most U.S. metros have seen steady reductions in particulate and ozone pollution since the 2010s as cleaner vehicles and power plants come online.
In 2014, Cass, Nebraska posted a median AQI of 22. By 2023 that figure was 17 — a drop of 5 AQI points cleaner across 10 years of EPA records.
Year-by-Year AQI in Cass, Nebraska
| Year | Median AQI | Good Days | Unhealthy Days | Dominant Pollutant |
|---|---|---|---|---|
| 2014 | 22 | 316 | 0 | PM10 |
| 2015 | 24 | 309 | 1 | PM10 |
| 2016 | 22 | 322 | 0 | PM10 |
| 2017 | 22 | 335 | 0 | PM10 |
| 2018 | 15 | 332 | 0 | PM10 |
| 2019 | 13 | 348 | 0 | PM10 |
| 2020 | 14 | 346 | 0 | PM10 |
| 2021 | 19 | 345 | 0 | PM10 |
| 2022 | 19 | 337 | 0 | PM10 |
| 2023 | 17 | 344 | 0 | PM10 |
Health Context for Cass, Nebraska
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.
Cass, Nebraska has an Air Quality Grade of A (excellent) with a 5-year median AQI of 16. The dominant pollutant is Coarse Particulate Matter (PM10), and air quality has been improving over the past decade.
The data source behind this answer is the EPA Air Quality System (AQS). Every figure on the page traces back to that source; the methodology page describes the inputs and the refresh cadence in full detail.
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.