Air Quality Rankings for Nebraska (2026)
Nebraska has 9 cities tracked by EPA air-quality monitors, with a state-wide 5-year median AQI of 30 — 11 points cleaner than the national average of AQI 41. Cass, Nebraska ranks #1 with the cleanest air (AQI 16, Grade A), while Douglas, Nebraska sits at the bottom (AQI 43, Grade B).
How Nebraska Compares
Nebraska has 9 cities tracked by EPA air-quality monitors, with a state-wide 5-year median AQI of 30 — 11 points cleaner than the national average of AQI 41. Cass, Nebraska ranks #1 with the cleanest air (AQI 16, Grade A), while Douglas, Nebraska sits at the bottom (AQI 43, Grade B). The rankings below are computed from the EPA Air Quality System (AQS), which aggregates daily AQI readings from federally certified monitors into annual averages. Cities are sorted by 5-year median AQI (lowest = cleanest = #1). The 5-year window smooths out year-to-year volatility from weather and wildfire events.
Nebraska is on an improving trajectory: 5 of 9 monitored cities show measurably cleaner air over the past decade, against just 1 that are getting worse. That mirrors the broader national pattern of falling particulate and ozone pollution as cleaner vehicles, cleaner power generation, and tighter industrial standards take effect.
The dominant pollutant across 6 of 9 Nebraska cities is Fine Particulate Matter (PM2.5). PM2.5 (fine particulate matter) is most often driven by combustion sources — vehicle exhaust, industrial emissions, residential wood burning, and increasingly wildfire smoke. It penetrates deep into lung tissue and the bloodstream and is the air pollutant most strongly linked to long-term health impacts. Other Nebraska cities report Ground-Level Ozone (2), Coarse Particulate Matter (PM10) (1) as their dominant concern.
The fastest-improving city in Nebraska is Sarpy, Nebraska, with median AQI falling by 1.1 points per year. Steady improvement at that pace usually reflects fleet turnover (older diesels retiring), upwind power-plant retirements, or tighter regional emissions controls.
The city with the steepest decline is Knox, Nebraska, where median AQI is rising by 0.4 points per year. Rapid deterioration in a single city usually points to either wildfire-smoke exposure (in the West) or a new local emissions source — a power plant, port, or freight corridor coming online.
Full Nebraska Ranking
| # | City | 5yr Avg AQI | Current AQI | Worst Pollutant | Trend | Grade |
|---|---|---|---|---|---|---|
| 1 | Cass, Nebraska | 16 | 17 | PM10 | Improving | A |
| 2 | Thomas, Nebraska | 17 | 17 | PM2.5 | Stable | B |
| 3 | Scotts Bluff, Nebraska | 24 | 21 | PM2.5 | Improving | B |
| 4 | Hall, Nebraska | 29 | 35 | PM2.5 | Stable | B |
| 5 | Washington, Nebraska | 31 | 33 | PM2.5 | Improving | B |
| 6 | Knox, Nebraska | 37 | 41 | Ozone | Worsening | C |
| 7 | Lancaster, Nebraska | 37 | 42 | Ozone | Stable | B |
| 8 | Sarpy, Nebraska | 38 | 37 | PM2.5 | Improving | B |
| 9 | Douglas, Nebraska | 43 | 45 | PM2.5 | Improving | B |
Air quality data for Nebraska is sourced from the EPA Air Quality System (AQS), which monitors outdoor air quality at thousands of stations nationwide.
Frequently Asked Questions
Cass, Nebraska has the best air quality in Nebraska with a 5-year average AQI of 16 and a Grade A (84/100). Its dominant pollutant is Coarse Particulate Matter (PM10) and the long-run trend is improving.
Douglas, Nebraska has the worst air quality in Nebraska with a 5-year average AQI of 43 and a Grade B (65/100). Its dominant pollutant is Fine Particulate Matter (PM2.5).
Nebraska has 9 cities with EPA air quality monitoring data, covering 2014-2023 of daily AQI measurements aggregated into annual averages.
Nebraska's state-wide 5-year median AQI is 30, 11 points cleaner than the national average of AQI 41. Nebraska is on an improving trajectory: 5 of 9 monitored cities show measurably cleaner air over the past decade, against just 1 that are getting worse. That mirrors the broader national pattern of falling particulate and ozone pollution as cleaner vehicles, cleaner power generation, and tighter industrial standards take effect.
Fine Particulate Matter (PM2.5) is the dominant pollutant in 6 of 9 monitored Nebraska cities. PM2.5 (fine particulate matter) is most often driven by combustion sources — vehicle exhaust, industrial emissions, residential wood burning, and increasingly wildfire smoke. It penetrates deep into lung tissue and the bloodstream and is the air pollutant most strongly linked to long-term health impacts.
Nebraska cities log an average of 2 days per year at "Unhealthy for Sensitive Groups" or worse, based on EPA monitor data over the last five years. Across all 9 Nebraska cities tracked, that totals 73 unhealthy days over the period.
Cities ranked by 5-year average AQI (lower is better). Grades factor in average AQI, trend direction, unhealthy days, and dominant pollutant.
The this entity category groups every U.S. air quality and pollution monitoring entity sharing this attribute. The list above is the data; the paragraphs below explain what the grouping means against the broader the EPA Air Quality System (AQS) distribution and how to read the relative rankings within the category.
For readers using this category as a starting point, the per-entity detail pages linked from the table above carry the underlying the EPA Air Quality System (AQS) data in full. The category-level view is the filter; the per-entity pages are the actual answer.
Source: EPA Outdoor Air Quality Data, 2026.