EnviroNearby

Lyon County, Nevada air quality history

Daily Air Quality Index summaries from EPA monitors in Lyon, Nevada, 2007–2025.

90%
Good days in 2025
41
Median daily AQI, 2025
0
Days above 100 in 2025
359
Days with an AQI in 2025 (of 365)

In 2025, EPA reported a daily Air Quality Index (AQI) for Lyon, Nevada on 359 days. 323 of those days (90%) were in the Good range, and the median daily AQI was 41. That median is about the same as the typical monitored county in Nevada (median 42 across 9 counties), and about the same as the typical monitored U.S. county (40). The main pollutant was ozone on 359 days. Across the years with fuller monitoring, the share of Good days rose: an average of 85% in 2008–2010 versus 91% in 2023–2025.

Years with fewer than 120 monitored days (2007) are shown in the table but left out of comparisons and trend statements.

How the days broke down each year

Each bar is one year. The colored segments show the share of monitored days that fell in each AQI category.

Share of monitored days in each AQI category, by year0%25%50%75%100%2007: Good 86 of 112 days2007: Moderate 26 of 112 days20072008: Good 134 of 169 days2008: Moderate 34 of 169 days2008: Unhealthy for Sensitive Groups 1 of 169 days2009: Good 143 of 161 days2009: Moderate 18 of 161 days20092010: Good 167 of 192 days2010: Moderate 24 of 192 days2010: Unhealthy for Sensitive Groups 1 of 192 days2011: Good 159 of 198 days2011: Moderate 35 of 198 days2011: Unhealthy for Sensitive Groups 4 of 198 days20112012: Good 130 of 212 days2012: Moderate 77 of 212 days2012: Unhealthy for Sensitive Groups 5 of 212 days2013: Good 135 of 208 days2013: Moderate 73 of 208 days20132014: Good 147 of 212 days2014: Moderate 63 of 212 days2014: Unhealthy for Sensitive Groups 2 of 212 days2015: Good 207 of 275 days2015: Moderate 64 of 275 days2015: Unhealthy for Sensitive Groups 4 of 275 days20152016: Good 282 of 352 days2016: Moderate 69 of 352 days2016: Unhealthy for Sensitive Groups 1 of 352 days2017: Good 307 of 363 days2017: Moderate 53 of 363 days2017: Unhealthy for Sensitive Groups 3 of 363 days20172018: Good 304 of 362 days2018: Moderate 50 of 362 days2018: Unhealthy for Sensitive Groups 8 of 362 days2019: Good 344 of 356 days2019: Moderate 12 of 356 days20192020: Good 308 of 356 days2020: Moderate 39 of 356 days2020: Unhealthy for Sensitive Groups 5 of 356 days2020: Unhealthy 3 of 356 days2020: Hazardous 1 of 356 days2021: Good 196 of 270 days2021: Moderate 67 of 270 days2021: Unhealthy for Sensitive Groups 7 of 270 days20212022: Good 329 of 355 days2022: Moderate 25 of 355 days2022: Unhealthy for Sensitive Groups 1 of 355 days2023: Good 325 of 349 days2023: Moderate 24 of 349 days20232024: Good 310 of 349 days2024: Moderate 39 of 349 days2025: Good 323 of 359 days2025: Moderate 36 of 359 days2025
  • Good
  • Moderate
  • Unhealthy for Sensitive Groups
  • Unhealthy
  • Very Unhealthy
  • Hazardous

Typical and high-end AQI over time

The median is the middle day of the year. The 90th percentile is the level that only the highest 10% of days exceeded.

Median and 90th-percentile daily AQI, by year0501002007: 90th percentile AQI 612008: 90th percentile AQI 672009: 90th percentile AQI 542010: 90th percentile AQI 542011: 90th percentile AQI 612012: 90th percentile AQI 802013: 90th percentile AQI 672014: 90th percentile AQI 712015: 90th percentile AQI 712016: 90th percentile AQI 612017: 90th percentile AQI 582018: 90th percentile AQI 582019: 90th percentile AQI 472020: 90th percentile AQI 592021: 90th percentile AQI 742022: 90th percentile AQI 492023: 90th percentile AQI 492024: 90th percentile AQI 512025: 90th percentile AQI 512007: Median AQI 452008: Median AQI 442009: Median AQI 392010: Median AQI 372011: Median AQI 442012: Median AQI 472013: Median AQI 472014: Median AQI 472015: Median AQI 452016: Median AQI 412017: Median AQI 422018: Median AQI 402019: Median AQI 382020: Median AQI 382021: Median AQI 412022: Median AQI 392023: Median AQI 412024: Median AQI 422025: Median AQI 412007200920112013201520172019202120232025
  • Median daily AQI
  • 90th-percentile daily AQI

Main pollutant by day, 2025

On each monitored day, the AQI reflects whichever measured pollutant had the highest index. This counts how many days each pollutant set the AQI. A pollutant that was not measured here cannot appear.

PollutantDays as main pollutantShare of monitored days
Ozone359100%

Year-by-year data

Annual AQI summary by year
YearDays with AQIGoodModerateUnhealthy for Sensitive GroupsUnhealthyVery UnhealthyHazardousMedian AQI90th pct.Max AQIMain pollutant
2025359323360000415184Ozone
2024349310390000425190Ozone
2023349325240000414987Ozone
20223553292510003949105Ozone
20212701966770004174133Ozone
20203563083953013859328Ozone
2019356344120000384771Ozone
20183623045080004058133Ozone
20173633075330004258112Ozone
20163522826910004161101Ozone
20152752076440004571108Ozone
20142121476320004771112Ozone
2013208135730000476790Ozone
20122121307750004780119Ozone
20111981593540004461133Ozone
20101921672410003754101Ozone
2009161143180000395493Ozone
20081691343410004467105Ozone
200711286260000456190Ozone

What this data can and can’t tell you

It is a county-level summary. EPA reports one AQI per day for the county, based on the monitors operating there. Air at a particular street, school or home can differ, especially near roads, industry or wildfire smoke.

It is not a health assessment. The AQI is EPA’s scale for communicating daily air quality. A county’s history can’t tell you what the health risk is for any particular person. For daily conditions and health guidance, see AirNow.

Rules change over time. EPA has revised AQI breakpoints, most recently for fine particles in 2024, so some year-to-year change can reflect the scale rather than the air.

Counties in Nevada with a similar median AQI in 2025

All monitored counties in Nevada

Source: U.S. EPA AirData, “Annual AQI by County” files for 2007–2025 (EPA download page). EPA file dates: 2026-06-26. Imported into EnviroNearby November 5, 2026. How we use this data · Report a problem