EnviroNearby

Chautauqua County, New York air quality history

Daily Air Quality Index summaries from EPA monitors in Chautauqua, New York, 1990–2025.

89%
Good days in 2025
36
Median daily AQI, 2025
1
Days above 100 in 2025
356
Days with an AQI in 2025 (of 365)

In 2025, EPA reported a daily Air Quality Index (AQI) for Chautauqua, New York on 356 days. 317 of those days (89%) were in the Good range, and the median daily AQI was 36. That median is about the same as the typical monitored county in New York (median 36 across 27 counties), and lower than the typical monitored U.S. county (40). The main pollutant was ozone on 338 days. Across the years with fuller monitoring, the share of Good days rose: an average of 83% in 1991–1993 versus 89% in 2023–2025.

Years with fewer than 120 monitored days (1990) 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%1990: Good 96 of 103 days1990: Moderate 5 of 103 days1990: Unhealthy for Sensitive Groups 2 of 103 days19901991: Good 311 of 357 days1991: Moderate 34 of 357 days1991: Unhealthy for Sensitive Groups 11 of 357 days1991: Unhealthy 1 of 357 days1992: Good 280 of 333 days1992: Moderate 42 of 333 days1992: Unhealthy for Sensitive Groups 8 of 333 days1992: Unhealthy 3 of 333 days1993: Good 262 of 335 days1993: Moderate 52 of 335 days1993: Unhealthy for Sensitive Groups 19 of 335 days1993: Unhealthy 2 of 335 days1994: Good 291 of 362 days1994: Moderate 46 of 362 days1994: Unhealthy for Sensitive Groups 25 of 362 days1995: Good 253 of 331 days1995: Moderate 54 of 331 days1995: Unhealthy for Sensitive Groups 20 of 331 days1995: Unhealthy 4 of 331 days19951996: Good 268 of 348 days1996: Moderate 57 of 348 days1996: Unhealthy for Sensitive Groups 21 of 348 days1996: Unhealthy 2 of 348 days1997: Good 272 of 324 days1997: Moderate 34 of 324 days1997: Unhealthy for Sensitive Groups 15 of 324 days1997: Unhealthy 3 of 324 days1998: Good 255 of 339 days1998: Moderate 49 of 339 days1998: Unhealthy for Sensitive Groups 27 of 339 days1998: Unhealthy 6 of 339 days1998: Very Unhealthy 2 of 339 days1999: Good 250 of 360 days1999: Moderate 68 of 360 days1999: Unhealthy for Sensitive Groups 31 of 360 days1999: Unhealthy 11 of 360 days2000: Good 255 of 366 days2000: Moderate 92 of 366 days2000: Unhealthy for Sensitive Groups 15 of 366 days2000: Unhealthy 3 of 366 days2000: Very Unhealthy 1 of 366 days20002001: Good 253 of 365 days2001: Moderate 82 of 365 days2001: Unhealthy for Sensitive Groups 19 of 365 days2001: Unhealthy 11 of 365 days2002: Good 238 of 364 days2002: Moderate 85 of 364 days2002: Unhealthy for Sensitive Groups 19 of 364 days2002: Unhealthy 21 of 364 days2002: Very Unhealthy 1 of 364 days2003: Good 258 of 365 days2003: Moderate 85 of 365 days2003: Unhealthy for Sensitive Groups 15 of 365 days2003: Unhealthy 5 of 365 days2003: Very Unhealthy 2 of 365 days2004: Good 262 of 365 days2004: Moderate 87 of 365 days2004: Unhealthy for Sensitive Groups 13 of 365 days2004: Unhealthy 3 of 365 days2005: Good 241 of 365 days2005: Moderate 94 of 365 days2005: Unhealthy for Sensitive Groups 24 of 365 days2005: Unhealthy 6 of 365 days20052006: Good 269 of 365 days2006: Moderate 74 of 365 days2006: Unhealthy for Sensitive Groups 21 of 365 days2006: Unhealthy 1 of 365 days2007: Good 257 of 365 days2007: Moderate 83 of 365 days2007: Unhealthy for Sensitive Groups 21 of 365 days2007: Unhealthy 4 of 365 days2008: Good 282 of 366 days2008: Moderate 74 of 366 days2008: Unhealthy for Sensitive Groups 8 of 366 days2008: Unhealthy 2 of 366 days2009: Good 296 of 365 days2009: Moderate 66 of 365 days2009: Unhealthy for Sensitive Groups 3 of 365 days2010: Good 271 of 365 days2010: Moderate 78 of 365 days2010: Unhealthy for Sensitive Groups 15 of 365 days2010: Unhealthy 1 of 365 days20102011: Good 293 of 365 days2011: Moderate 66 of 365 days2011: Unhealthy for Sensitive Groups 5 of 365 days2011: Unhealthy 1 of 365 days2012: Good 280 of 366 days2012: Moderate 69 of 366 days2012: Unhealthy for Sensitive Groups 15 of 366 days2012: Unhealthy 2 of 366 days2013: Good 298 of 347 days2013: Moderate 48 of 347 days2013: Unhealthy for Sensitive Groups 1 of 347 days2014: Good 299 of 357 days2014: Moderate 56 of 357 days2014: Unhealthy for Sensitive Groups 2 of 357 days2015: Good 290 of 362 days2015: Moderate 67 of 362 days2015: Unhealthy for Sensitive Groups 5 of 362 days20152016: Good 315 of 363 days2016: Moderate 45 of 363 days2016: Unhealthy for Sensitive Groups 3 of 363 days2017: Good 298 of 346 days2017: Moderate 46 of 346 days2017: Unhealthy for Sensitive Groups 2 of 346 days2018: Good 300 of 358 days2018: Moderate 54 of 358 days2018: Unhealthy for Sensitive Groups 4 of 358 days2019: Good 302 of 343 days2019: Moderate 40 of 343 days2019: Unhealthy for Sensitive Groups 1 of 343 days2020: Good 332 of 363 days2020: Moderate 31 of 363 days20202021: Good 300 of 361 days2021: Moderate 60 of 361 days2021: Unhealthy for Sensitive Groups 1 of 361 days2022: Good 322 of 355 days2022: Moderate 29 of 355 days2022: Unhealthy for Sensitive Groups 4 of 355 days2023: Good 322 of 363 days2023: Moderate 36 of 363 days2023: Unhealthy for Sensitive Groups 5 of 363 days2024: Good 326 of 363 days2024: Moderate 36 of 363 days2024: Unhealthy for Sensitive Groups 1 of 363 days2025: Good 317 of 356 days2025: Moderate 38 of 356 days2025: Unhealthy for Sensitive Groups 1 of 356 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 year0501001501990: 90th percentile AQI 461991: 90th percentile AQI 581992: 90th percentile AQI 711993: 90th percentile AQI 841994: 90th percentile AQI 841995: 90th percentile AQI 901996: 90th percentile AQI 871997: 90th percentile AQI 641998: 90th percentile AQI 1081999: 90th percentile AQI 1152000: 90th percentile AQI 872001: 90th percentile AQI 932002: 90th percentile AQI 1052003: 90th percentile AQI 842004: 90th percentile AQI 842005: 90th percentile AQI 972006: 90th percentile AQI 842007: 90th percentile AQI 842008: 90th percentile AQI 712009: 90th percentile AQI 602010: 90th percentile AQI 742011: 90th percentile AQI 642012: 90th percentile AQI 802013: 90th percentile AQI 552014: 90th percentile AQI 562015: 90th percentile AQI 612016: 90th percentile AQI 542017: 90th percentile AQI 542018: 90th percentile AQI 612019: 90th percentile AQI 532020: 90th percentile AQI 492021: 90th percentile AQI 572022: 90th percentile AQI 502023: 90th percentile AQI 542024: 90th percentile AQI 512025: 90th percentile AQI 521990: Median AQI 281991: Median AQI 321992: Median AQI 351993: Median AQI 351994: Median AQI 351995: Median AQI 341996: Median AQI 371997: Median AQI 351998: Median AQI 351999: Median AQI 402000: Median AQI 402001: Median AQI 412002: Median AQI 412003: Median AQI 402004: Median AQI 392005: Median AQI 432006: Median AQI 402007: Median AQI 402008: Median AQI 412009: Median AQI 382010: Median AQI 402011: Median AQI 392012: Median AQI 402013: Median AQI 372014: Median AQI 382015: Median AQI 392016: Median AQI 372017: Median AQI 382018: Median AQI 372019: Median AQI 382020: Median AQI 362021: Median AQI 382022: Median AQI 362023: Median AQI 372024: Median AQI 362025: Median AQI 3619901995200020052010201520202025
  • 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
Ozone33895%
Fine particles (PM2.5)185%

Year-by-year data

Annual AQI summary by year
YearDays with AQIGoodModerateUnhealthy for Sensitive GroupsUnhealthyVery UnhealthyHazardousMedian AQI90th pct.Max AQIMain pollutant
20253563173810003652108Ozone
20243633263610003651105Ozone
20233633223650003754133Ozone
20223553222940003650140Ozone
20213613006010003857105Ozone
2020363332310000364993Ozone
20193433024010003853105Ozone
20183583005440003761126Ozone
20173462984620003854129Ozone
20163633154530003754140Ozone
20153622906750003961126Ozone
20143572995620003856112Ozone
20133472984810003755119Ozone
201236628069152004080197Ozone
20113652936651003964159Ozone
201036527178151004074159Ozone
20093652966630003860133Ozone
20083662827482004171156Ozone
200736525783214004084169Ozone
200636526974211004084151Ozone
200536524194246004397179Ozone
200436526287133003984161Ozone
200336525885155204084214Ozone
20023642388519211041105206Ozone
2001365253821911004193195Ozone
200036625592153104087204Ozone
19993602506831110040115185Ozone
1998339255492762035108201Ozone
199732427234153003564172Ozone
199634826857212003787161Ozone
199533125354204003490161Ozone
199436229146250003584140Ozone
199333526252192003584169Ozone
19923332804283003571174Ozone
199135731134111003258156Ozone
199010396520002846101Ozone

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 New York with a similar median AQI in 2025

All monitored counties in New York

Source: U.S. EPA AirData, “Annual AQI by County” files for 1990–2025 (EPA download page). EPA file dates: 2026-06-26. Imported into EnviroNearby November 5, 2026. How we use this data · Report a problem