Median AQI
64
Moderate
Nevada · County air quality · 2025
Clark County, Nevada
Median AQI 64 (Moderate). 25.6% of monitored days rated Good, direct from EPA Air Quality System stations.
- 64
- Median AQI
- 25.6%
- Good-air days
- 0
- Unhealthy days
- 1%
- Cleaner than US counties
The verdict
According to EPA Air Quality System monitoring data, Clark County's air is moderate on balance, among the most polluted counties nationally, a median AQI of 64 with 25.6% of 274 monitored days in the Good band, driven mainly by Ozone.
- 64
- median AQI · Moderate
- 25.6%
- days rated Good
- Ozone
- main pollutant
- 1%
- cleaner than US counties
Not one day crossed into the Unhealthy tier; the worst single reading was AQI 138.
Data updated July 2026
- Good · 70 d · 25.5%
- Moderate · 178 d · 65.0%
- USG · 26 d · 9.5%
How did Clark County's air break down in 2025?
Across 274 monitored days, 70 fell in the Good band (AQI 0–50) and 0 reached Unhealthy or worse. The worst single day peaked at AQI 138 (USG).
EPA AQS →Air quality data from EPA Air Quality System (2025). 274 days monitored. Median AQI: 64 (Moderate).
Insights: Clark County, Nevada. EPA monitors recorded a median Air Quality Index of 64 across 274 measured days in 2025, earning a Moderate classification and a Poor health grade. Of those days, 70 (26%) fell in the Good band (AQI 0–50), 178 (65%) registered Moderate readings, and 26 (9%) reached Unhealthy for Sensitive Groups. The 90th-percentile AQI settled at 100, while the worst single-day peak hit 138 (USG). Residents averaged about 7.7 clean-air days per 30-day window during the monitoring year.
The full pollutant mix ranks as Ozone (203 days), PM2.5 (52 days), PM10 (18 days), CO (1 days). Across the 2020–2025 trend window, good days shifted by -22 and the median AQI moved -1 points, placing the multi-year trajectory at stable. The worst single reading over the 2020–2025 window was AQI 138, usg but never Unhealthy. Nearby counties show comparable readings: Carson City (79.3% good, AQI 45); Churchill (81.0% good, AQI 43); Douglas (90.9% good, AQI 22); Elko (90.8% good, AQI 19); Lyon (83.9% good, AQI 44); Nye (91.2% good, AQI 24).
Air Quality Summary
Good Days
25.6%
70 of 274 monitored days
-49.5pp vs 75% target
Max AQI Recorded
138
USG
Health Grade
Poor
90th-pct AQI 100
Clark County, Good days share 25.6%
National avg
Share of monitored days at AQI 0-50 (Good band).
Clark County, Unhealthy-or-worse share 0.0%
National avg
Share of monitored days above AQI 150 (Unhealthy or worse). Bar maxes at 10% (worst-county ceiling).
AQI Day Breakdown (2025)
Distribution of 274 monitored days across EPA AQI categories.
Good
70
26%
Moderate
178
65%
USG
26
9%
Unhealthy
0
0%
Very Unhealthy
0
0%
Hazardous
0
0%
Pollutant Breakdown
Days where each pollutant was the primary driver of AQI readings in Clark County.
- Ozone · 203 days · 74.1%
- PM2.5 · 52 days · 19.0%
- PM10 · 18 days · 6.6%
- CO · 1 days · 0.4%
Health Impact Assessment
Poor
Clark County's air quality is rated Poor based on 25.6% good air days. No unhealthy air days were recorded in 2025.
Air quality is acceptable most days, but 26 days reached "Unhealthy for Sensitive Groups" (AQI 101-150). Sensitive groups should monitor real-time conditions at AirNow.gov.
The dominant pollutant is Ozone, driving AQI on 203 of 274 monitored days.
5-Year Air Quality Trend
Air quality is stable in Clark County. Best year: 2023 (106 good days).
| Year | Good | Moderate | USG | Unhealthy | Median AQI | Max AQI |
|---|---|---|---|---|---|---|
| 2020 | 92 | 249 | 22 | 3 | 65 | 174 |
| 2021 | 87 | 244 | 31 | 3 | 62 | 183 |
| 2022 | 71 | 268 | 20 | 3 | 64 | 480 |
| 2023 | 106 | 233 | 25 | 1 | 61 | 197 |
| 2024 | 90 | 236 | 39 | 1 | 64 | 170 |
| 2025 | 70 | 178 | 26 | 0 | 64 | 138 |
How does Clark County compare?
How Clark County compares
Good-day share worse than US avg
Clark County 25.6%
Carson City County, Nevada 79.3%
US average 76.5%
Median AQI worse than US avg
Clark County 64
Carson City County, Nevada 45
US average 38
Unhealthy days / yr about average
Clark County 0
Carson City County, Nevada 0
US average 0
Other Counties in Nevada
Air quality comparison for nearby counties in Nevada.
Counties with Similar Air Quality
Counties across the US with a similar median AQI to Clark County.
Imperial County, California
AQI 64 · 27.4% good
Harris County, Texas
AQI 63 · 8.8% good
Pinal County, Arizona
AQI 66 · 24.6% good
Kern County, California
AQI 61 · 23.8% good
Bernalillo County, New Mexico
AQI 59 · 23.7% good
Tulare County, California
AQI 59 · 29.7% good
What Clark County's air means for you
The air here stays in the breathable range year-round, with Ozone the main thing to watch.
- Sensitive groups (asthma, heart conditions, children, older adults) should check the AQI on high-Ozone days, the guide explains what a median of 64 means for exposure. Health guidance
- See how Clark County ranks against every monitored U.S. county on Good-day share. County rankings
- Compare Clark County with its Nevada neighbours before drawing a conclusion about the region. All of Nevada
Based on 274 EPA-monitored days in 2025; figures reflect only days the monitors reported. Source: EPA Air Quality System annual summaries.
More Air Quality Data
Air Quality Guides
Frequently Asked Questions
What is the air quality in Clark County, Nevada? ▼
Clark County has a median Air Quality Index (AQI) of 64, rated "Moderate." 25.6% of monitored days (70 out of 274) had good air quality in 2025.
What is the main pollutant in Clark County? ▼
The primary pollutant in Clark County is Ozone (O3), which was the main AQI driver on 203 days (74% of monitored days). Can trigger asthma, reduce lung function, and cause chest pain.
How many unhealthy air days does Clark County have? ▼
In 2025, Clark County recorded 0 unhealthy air days (0 Unhealthy, 0 Very Unhealthy, 0 Hazardous). The maximum AQI reached 138.
Is the air quality in Clark County getting better or worse? ▼
Air quality in Clark County is stable based on 5-year trends (2020-2025). Best year: 2023 with 106 good days. Worst year: 2025 with 70 good days.
What does AQI 64 mean for health? ▼
Clark County's median AQI of 64 falls in the "Moderate" category. See the <a href="/guides/understanding-aqi" class="underline">AQI category guide</a> for what each range means for health.
How does Clark County compare to other counties in Nevada? ▼
Clark County has 25.6% good air days. Nearby counties in Nevada: Carson City (79.3% good), Churchill (81.0% good), Douglas (90.9% good), Elko (90.8% good), Lyon (83.9% good), Nye (91.2% good).
What is the 90th percentile AQI in Clark County? ▼
The 90th percentile AQI for Clark County is 100, meaning 90% of monitored days had an AQI at or below this level. The maximum AQI recorded was 138 (USG).
Data Sources
Primary Source: U.S. Environmental Protection Agency (EPA), Air Quality System (AQS), Annual AQI by County dataset, 2020–2025 (aqs.epa.gov). For current conditions (not shown here — this page is historical annual data), see EPA AirNow (airnow.gov). See our methodology for how AQI, median, and coverage figures are computed.
Informational only, not professional advice. Data from EPA AQS. See our disclaimer.
Every figure on PlainAir is rendered directly from EPA AQS air-quality monitoring data, no number is typed in by an editor. This page draws directly on EPA AQS air-quality monitoring data, no figure is typed in by an editor. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error.