EnviroNearby

Denali, Alaska air quality history

Daily Air Quality Index summaries from EPA monitors in Denali, Alaska, 1987–2025.

100%
Good days in 2025
33
Median daily AQI, 2025
0
Days above 100 in 2025
362
Days with an AQI in 2025 (of 365)

In 2025, EPA reported a daily Air Quality Index (AQI) for Denali, Alaska on 362 days. 361 of those days (100%) were in the Good range, and the median daily AQI was 33. That median is higher than the typical monitored county in Alaska (median 26 across 5 counties), and lower than the typical monitored U.S. county (40). The main pollutant was ozone on 355 days. Across the years with fuller monitoring, the share of Good days held roughly steady: an average of 100% in 1987–1989 versus 99% in 2023–2025.

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%1987: Good 148 of 148 days19871988: Good 336 of 337 days1988: Moderate 1 of 337 days1989: Good 278 of 278 days1990: Good 315 of 318 days1990: Moderate 3 of 318 days1991: Good 314 of 317 days1991: Moderate 3 of 317 days1992: Good 354 of 354 days19921993: Good 349 of 352 days1993: Moderate 3 of 352 days1994: Good 358 of 359 days1994: Moderate 1 of 359 days1995: Good 346 of 349 days1995: Moderate 3 of 349 days1996: Good 320 of 321 days1996: Moderate 1 of 321 days1997: Good 320 of 323 days1997: Moderate 2 of 323 days1997: Unhealthy for Sensitive Groups 1 of 323 days19971998: Good 352 of 356 days1998: Moderate 4 of 356 days1999: Good 359 of 362 days1999: Moderate 3 of 362 days2000: Good 361 of 363 days2000: Moderate 1 of 363 days2000: Unhealthy for Sensitive Groups 1 of 363 days2001: Good 355 of 362 days2001: Moderate 7 of 362 days2002: Good 338 of 347 days2002: Moderate 7 of 347 days2002: Unhealthy for Sensitive Groups 2 of 347 days20022003: Good 363 of 364 days2003: Moderate 1 of 364 days2004: Good 360 of 363 days2004: Moderate 3 of 363 days2005: Good 361 of 365 days2005: Moderate 4 of 365 days2006: Good 357 of 359 days2006: Moderate 2 of 359 days2007: Good 354 of 356 days2007: Moderate 2 of 356 days20072008: Good 353 of 360 days2008: Moderate 5 of 360 days2008: Unhealthy for Sensitive Groups 2 of 360 days2009: Good 350 of 359 days2009: Moderate 8 of 359 days2009: Unhealthy for Sensitive Groups 1 of 359 days2010: Good 363 of 363 days2011: Good 363 of 365 days2011: Moderate 2 of 365 days2012: Good 363 of 365 days2012: Moderate 2 of 365 days20122013: Good 357 of 359 days2013: Moderate 2 of 359 days2014: Good 333 of 341 days2014: Moderate 8 of 341 days2015: Good 355 of 363 days2015: Moderate 8 of 363 days2016: Good 357 of 358 days2016: Moderate 1 of 358 days2017: Good 359 of 360 days2017: Moderate 1 of 360 days20172018: Good 361 of 364 days2018: Moderate 3 of 364 days2019: Good 355 of 360 days2019: Moderate 5 of 360 days2020: Good 356 of 358 days2020: Moderate 2 of 358 days2021: Good 360 of 363 days2021: Moderate 3 of 363 days2022: Good 328 of 338 days2022: Moderate 10 of 338 days20222023: Good 350 of 350 days2024: Good 357 of 362 days2024: Moderate 5 of 362 days2025: Good 361 of 362 days2025: Moderate 1 of 362 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 year0501001987: 90th percentile AQI 361988: 90th percentile AQI 391989: 90th percentile AQI 391990: 90th percentile AQI 391991: 90th percentile AQI 391992: 90th percentile AQI 411993: 90th percentile AQI 391994: 90th percentile AQI 401995: 90th percentile AQI 401996: 90th percentile AQI 431997: 90th percentile AQI 431998: 90th percentile AQI 451999: 90th percentile AQI 442000: 90th percentile AQI 342001: 90th percentile AQI 452002: 90th percentile AQI 442003: 90th percentile AQI 442004: 90th percentile AQI 442005: 90th percentile AQI 402006: 90th percentile AQI 442007: 90th percentile AQI 422008: 90th percentile AQI 442009: 90th percentile AQI 442010: 90th percentile AQI 442011: 90th percentile AQI 442012: 90th percentile AQI 432013: 90th percentile AQI 442014: 90th percentile AQI 442015: 90th percentile AQI 442016: 90th percentile AQI 412017: 90th percentile AQI 422018: 90th percentile AQI 442019: 90th percentile AQI 442020: 90th percentile AQI 422021: 90th percentile AQI 412022: 90th percentile AQI 442023: 90th percentile AQI 422024: 90th percentile AQI 432025: 90th percentile AQI 431987: Median AQI 301988: Median AQI 311989: Median AQI 301990: Median AQI 311991: Median AQI 301992: Median AQI 311993: Median AQI 311994: Median AQI 311995: Median AQI 301996: Median AQI 311997: Median AQI 361998: Median AQI 331999: Median AQI 312000: Median AQI 282001: Median AQI 342002: Median AQI 332003: Median AQI 332004: Median AQI 302005: Median AQI 322006: Median AQI 342007: Median AQI 332008: Median AQI 312009: Median AQI 342010: Median AQI 332011: Median AQI 342012: Median AQI 322013: Median AQI 322014: Median AQI 312015: Median AQI 352016: Median AQI 332017: Median AQI 342018: Median AQI 352019: Median AQI 362020: Median AQI 332021: Median AQI 332022: Median AQI 342023: Median AQI 332024: Median AQI 352025: Median AQI 33198719921997200220072012201720222025
  • 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
Ozone35598%
Fine particles (PM2.5)72%

Year-by-year data

Annual AQI summary by year
YearDays with AQIGoodModerateUnhealthy for Sensitive GroupsUnhealthyVery UnhealthyHazardousMedian AQI90th pct.Max AQIMain pollutant
202536236110000334354Ozone
202436235750000354377Ozone
202335035000000334250Ozone
2022338328100000344482Ozone
202136336030000334174Ozone
202035835620000334254Ozone
201936035550000364482Ozone
201836436130000354458Ozone
201736035910000344252Ozone
201635835710000334154Ozone
201536335580000354490Ozone
201434133380000314480Ozone
201335935720000324458Ozone
201236536320000324358Ozone
201136536320000344461Ozone
201036336300000334449Ozone
2009359350810003444117Ozone
2008360353520003144119Ozone
200735635420000334251Ozone
200635935720000344467Ozone
200536536140000324093Ozone
200436336030000304480Ozone
200336436310000334471Ozone
2002347338720003344113Ozone
200136235570000344571Ozone
2000363361110002834106Ozone
199936235930000314469Ozone
199835635240000334558Ozone
1997323320210003643101Ozone
199632132010000314361Ozone
199534934630000304061Ozone
199435935810000314051Ozone
199335234930000313955Ozone
199235435400000314148Ozone
199131731430000303964Ozone
199031831530000313966Ozone
198927827800000303944Ozone
198833733610000313951Ozone
198714814800000303641Ozone

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 Alaska with a similar median AQI in 2025

All monitored counties in Alaska

Source: U.S. EPA AirData, “Annual AQI by County” files for 1987–2025 (EPA download page). EPA file dates: 2026-06-26. Imported into EnviroNearby November 5, 2026. How we use this data · Report a problem