What Is the Air Quality in Clark, Nevada?
Clark, Nevada has an Air Quality Grade of D (poor) with a 5-year median AQI of 62. The dominant pollutant is Ground-Level Ozone, and air quality has been stable over the past decade.
Clark, Nevada Air Quality Snapshot
| Air Quality Grade | D43/100 |
| 5-Year Median AQI | 62 (Moderate) |
| Most Recent Median AQI (2023) | 61 (Moderate) |
| Dominant Pollutant | Ground-Level Ozone |
| 10-Year Trend | Stable (+0.20 AQI/yr) |
| Unhealthy Days (last 5 yr) | 116 |
| National Rank (cleanest = #1) | #1009 of 1,020 (99th most polluted percentile) |
| Nevada Rank | #9 of 9 |
What Does the D Grade Mean?
Clark, Nevada earns a D — air quality falls below the U.S. average, with a 5-year median AQI of 62. Residents with asthma, COPD, heart disease, or young children should watch daily AQI forecasts and limit outdoor exertion when alerts go out.
Clark, Nevada's 5-year median AQI of 62 is 21 points above the national average of 41 — meaningfully more polluted than the typical U.S. metro tracked here. Within Nevada, Clark, Nevada runs more polluted than the state average of 39 — local sources or geography are concentrating pollution above the state's typical reading.
For context within Nevada: Douglas, Nevada currently holds the state's cleanest grade (A, AQI 22), while Washoe, Nevada sits at the bottom (C, AQI 50).
What's in Clark, Nevada's Air?
The dominant pollutant in Clark, Nevada is Ground-Level Ozone. Ground-level ozone forms when sunlight reacts with vehicle exhaust and industrial emissions. It is worst on hot, sunny, stagnant summer days. Ozone irritates the lungs, triggers asthma attacks, and reduces lung function — even healthy adults can feel chest tightness and shortness of breath after exercising in elevated ozone.
Days by Dominant Pollutant (2023)
| Pollutant | Days as Dominant | Share of Year |
|---|---|---|
| Ground-Level Ozone | 247 | 68% |
| Fine Particulate Matter (PM2.5) | 101 | 28% |
| Coarse Particulate Matter (PM10) | 16 | 4% |
| Nitrogen Dioxide | 1 | 0% |
Is the Air Getting Better or Worse?
Air quality in Clark, Nevada 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 2014, Clark, Nevada posted a median AQI of 61. By 2023 that figure was 61 — a flat reading of 0 AQI points across 10 years of EPA records.
Year-by-Year AQI in Clark, Nevada
| Year | Median AQI | Good Days | Unhealthy Days | Dominant Pollutant |
|---|---|---|---|---|
| 2014 | 61 | 72 | 16 | Ozone |
| 2015 | 61 | 90 | 23 | Ozone |
| 2016 | 61 | 79 | 26 | Ozone |
| 2017 | 61 | 100 | 29 | Ozone |
| 2018 | 63 | 104 | 49 | Ozone |
| 2019 | 58 | 128 | 5 | Ozone |
| 2020 | 65 | 92 | 25 | Ozone |
| 2021 | 62 | 87 | 34 | Ozone |
| 2022 | 64 | 71 | 26 | Ozone |
| 2023 | 61 | 106 | 26 | Ozone |
Health Context for Clark, Nevada
Across the past five years, this area has logged 116 days where AQI rose into the "Unhealthy for Sensitive Groups" range or worse — about 23 days per year, or roughly one every five to seven days. That is well above the national norm and explains the D grade.
Treat daily AQI forecasts as essential input. On flagged days, sensitive groups (asthma, COPD, heart disease, pregnancy, young children, older adults) should limit outdoor exertion and keep windows closed. A HEPA air cleaner sized to a bedroom or family room can cut indoor PM2.5 by 80%+ during smoke or pollution events. Because ozone peaks in the afternoon on hot sunny days, plan outdoor exercise for early morning or after sunset on bad-air days.
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.
Clark, Nevada has an Air Quality Grade of D (poor) with a 5-year median AQI of 62. The dominant pollutant is Ground-Level Ozone, and air quality has been stable 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.