Median AQI
45
Good
Nevada · County air quality · 2025
Carson City County, Nevada
Median AQI 45 (Good). 79.3% of monitored days rated Good, direct from EPA Air Quality System stations.
- 45
- Median AQI
- 79.3%
- Good-air days
- 0
- Unhealthy days
- 50%
- Cleaner than US counties
The verdict
According to EPA Air Quality System monitoring data, Carson City County's air is good on balance, cleaner than the median US county, a median AQI of 45 with 79.3% of 179 monitored days in the Good band, driven mainly by Ozone.
- 45
- median AQI · Good
- 79.3%
- days rated Good
- Ozone
- main pollutant
- 50%
- cleaner than US counties
Not one day crossed into the Unhealthy tier; the worst single reading was AQI 80.
Data updated July 2026
- Good · 142 d · 79.3%
- Moderate · 37 d · 20.7%
How did Carson City County's air break down in 2025?
Across 179 monitored days, 142 fell in the Good band (AQI 0–50) and 0 reached Unhealthy or worse. The worst single day peaked at AQI 80 (Moderate).
EPA AQS →Air quality data from EPA Air Quality System (2025). 179 days monitored. Median AQI: 45 (Good).
Insights: Carson City County, Nevada. EPA monitors recorded a median Air Quality Index of 45 across 179 measured days in 2025, earning a Good classification and a Good health grade. Of those days, 142 (79%) fell in the Good band (AQI 0–50), 37 (21%) registered Moderate readings, and 0 (0%) reached Unhealthy for Sensitive Groups. The 90th-percentile AQI settled at 56, while the worst single-day peak hit 80 (Moderate). Residents averaged about 23.8 clean-air days per 30-day window during the monitoring year.
The full pollutant mix ranks as Ozone (128 days), PM2.5 (51 days). Across the 2020–2025 trend window, good days shifted by -142 and the median AQI moved +3 points, placing the multi-year trajectory at stable. The worst single reading over the 2020–2025 window was AQI 80, moderate but never Unhealthy. Nearby counties show comparable readings: Churchill (81.0% good, AQI 43); Clark (25.6% good, AQI 64); 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
79.3%
142 of 179 monitored days
4.3pp vs 75% target
Max AQI Recorded
80
Moderate
Health Grade
Good
90th-pct AQI 56
Carson City County, Good days share 79.3%
National avg
Share of monitored days at AQI 0-50 (Good band).
Carson City 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 179 monitored days across EPA AQI categories.
Good
142
79%
Moderate
37
21%
USG
0
0%
Unhealthy
0
0%
Very Unhealthy
0
0%
Hazardous
0
0%
Pollutant Breakdown
Days where each pollutant was the primary driver of AQI readings in Carson City County.
- Ozone · 128 days · 71.5%
- PM2.5 · 51 days · 28.5%
Health Impact Assessment
Good
Carson City County's air quality is rated Good based on 79.3% good air days. No unhealthy air days were recorded in 2025.
Air quality was acceptable on 79.3% of monitored days in 2025, with a median AQI of 45. Unusually sensitive people can check real-time conditions at AirNow.gov during high-pollution events.
The dominant pollutant is Ozone, driving AQI on 128 of 179 monitored days.
5-Year Air Quality Trend
Air quality is stable in Carson City County. Best year: 2022 (290 good days).
| Year | Good | Moderate | USG | Unhealthy | Median AQI | Max AQI |
|---|---|---|---|---|---|---|
| 2020 | 284 | 62 | 12 | 6 | 42 | 210 |
| 2021 | 273 | 64 | 9 | 12 | 42 | 304 |
| 2022 | 290 | 65 | 5 | 2 | 44 | 227 |
| 2023 | 236 | 126 | 1 | 0 | 47 | 105 |
| 2024 | 270 | 95 | 1 | 0 | 45 | 105 |
| 2025 | 142 | 37 | 0 | 0 | 45 | 80 |
How does Carson City County compare?
How Carson City County compares
Good-day share better than US avg
Carson City County 79.3%
Churchill County, Nevada 81.0%
US average 76.5%
Median AQI worse than US avg
Carson City County 45
Churchill County, Nevada 43
US average 38
Unhealthy days / yr about average
Carson City County 0
Churchill 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 Carson City County.
Adair County, Oklahoma
AQI 45 · 59.2% good
Allen County, Indiana
AQI 45 · 58.2% good
Atascosa County, Texas
AQI 45 · 58.0% good
Baker County, Florida
AQI 45 · 69.1% good
Clinton County, Iowa
AQI 45 · 59.9% good
Comanche County, Oklahoma
AQI 45 · 63.8% good
What Carson City 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 45 means for exposure. Health guidance
- See how Carson City County ranks against every monitored U.S. county on Good-day share. County rankings
- Compare Carson City County with its Nevada neighbours before drawing a conclusion about the region. All of Nevada
Based on 179 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 Carson City County, Nevada? ▼
Carson City County has a median Air Quality Index (AQI) of 45, rated "Good." 79.3% of monitored days (142 out of 179) had good air quality in 2025.
What is the main pollutant in Carson City County? ▼
The primary pollutant in Carson City County is Ozone (O3), which was the main AQI driver on 128 days (72% of monitored days). Can trigger asthma, reduce lung function, and cause chest pain.
How many unhealthy air days does Carson City County have? ▼
In 2025, Carson City County recorded 0 unhealthy air days (0 Unhealthy, 0 Very Unhealthy, 0 Hazardous). The maximum AQI reached 80.
Is the air quality in Carson City County getting better or worse? ▼
Air quality in Carson City County is stable based on 5-year trends (2020-2025). Best year: 2022 with 290 good days. Worst year: 2025 with 142 good days.
What does AQI 45 mean for health? ▼
Carson City County's median AQI of 45 falls in the "Good" category. See the <a href="/guides/understanding-aqi" class="underline">AQI category guide</a> for what each range means for health.
How does Carson City County compare to other counties in Nevada? ▼
Carson City County has 79.3% good air days. Nearby counties in Nevada: Churchill (81.0% good), Clark (25.6% good), Douglas (90.9% good), Elko (90.8% good), Lyon (83.9% good), Nye (91.2% good).
What is the 90th percentile AQI in Carson City County? ▼
The 90th percentile AQI for Carson City County is 56, meaning 90% of monitored days had an AQI at or below this level. The maximum AQI recorded was 80 (Moderate).
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.