EnviroNearby

Herkimer County, New York air quality history

Daily Air Quality Index summaries from EPA monitors in Herkimer, New York, 1990–2019.

100%
Good days in 2019
29
Median daily AQI, 2019
0
Days above 100 in 2019
185
Days with an AQI in 2019 (of 365)

In 2019, EPA reported a daily Air Quality Index (AQI) for Herkimer, New York on 185 days. 185 of those days (100%) were in the Good range, and the median daily AQI was 29. That median is lower than the typical monitored county in New York (median 37 across 29 counties), and lower than the typical monitored U.S. county (41). The main pollutant was ozone on 185 days. Across the years with fuller monitoring, the share of Good days rose: an average of 93% in 1992–1994 versus 98% in 2017–2019.

EPA did not report an AQI for every day of 2019 here (185 of 365 days). Figures describe monitored days only; seasonal monitoring (for example, ozone measured only in warmer months) can make a county look cleaner or dirtier than a full-year record would.

The most recent year with data for this county is 2019; EPA's files for 2020–2025 contain no row for it, which usually means its monitors stopped reporting.

Years with fewer than 120 monitored days (1990, 1991) 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 28 of 28 days19901991: Good 55 of 56 days1991: Moderate 1 of 56 days1992: Good 277 of 300 days1992: Moderate 19 of 300 days1992: Unhealthy for Sensitive Groups 3 of 300 days1992: Unhealthy 1 of 300 days1993: Good 335 of 358 days1993: Moderate 23 of 358 days1994: Good 334 of 359 days1994: Moderate 23 of 359 days1994: Unhealthy for Sensitive Groups 2 of 359 days1995: Good 331 of 356 days1995: Moderate 20 of 356 days1995: Unhealthy for Sensitive Groups 5 of 356 days19951996: Good 338 of 358 days1996: Moderate 19 of 358 days1996: Unhealthy for Sensitive Groups 1 of 358 days1997: Good 331 of 360 days1997: Moderate 23 of 360 days1997: Unhealthy for Sensitive Groups 6 of 360 days1998: Good 329 of 359 days1998: Moderate 26 of 359 days1998: Unhealthy for Sensitive Groups 4 of 359 days1999: Good 288 of 327 days1999: Moderate 32 of 327 days1999: Unhealthy for Sensitive Groups 7 of 327 days2000: Good 335 of 351 days2000: Moderate 14 of 351 days2000: Unhealthy for Sensitive Groups 1 of 351 days2000: Unhealthy 1 of 351 days20002001: Good 318 of 353 days2001: Moderate 28 of 353 days2001: Unhealthy for Sensitive Groups 7 of 353 days2002: Good 319 of 353 days2002: Moderate 25 of 353 days2002: Unhealthy for Sensitive Groups 8 of 353 days2002: Unhealthy 1 of 353 days2003: Good 315 of 344 days2003: Moderate 24 of 344 days2003: Unhealthy for Sensitive Groups 3 of 344 days2003: Unhealthy 2 of 344 days2004: Good 338 of 359 days2004: Moderate 20 of 359 days2004: Unhealthy for Sensitive Groups 1 of 359 days2005: Good 321 of 356 days2005: Moderate 33 of 356 days2005: Unhealthy for Sensitive Groups 2 of 356 days20052006: Good 336 of 356 days2006: Moderate 18 of 356 days2006: Unhealthy for Sensitive Groups 2 of 356 days2007: Good 327 of 351 days2007: Moderate 19 of 351 days2007: Unhealthy for Sensitive Groups 5 of 351 days2008: Good 334 of 361 days2008: Moderate 24 of 361 days2008: Unhealthy for Sensitive Groups 3 of 361 days2009: Good 338 of 362 days2009: Moderate 23 of 362 days2009: Unhealthy for Sensitive Groups 1 of 362 days2010: Good 332 of 359 days2010: Moderate 26 of 359 days2010: Unhealthy for Sensitive Groups 1 of 359 days20102011: Good 340 of 354 days2011: Moderate 14 of 354 days2012: Good 340 of 359 days2012: Moderate 19 of 359 days2013: Good 348 of 359 days2013: Moderate 11 of 359 days2014: Good 350 of 357 days2014: Moderate 7 of 357 days2015: Good 351 of 360 days2015: Moderate 9 of 360 days20152016: Good 337 of 347 days2016: Moderate 6 of 347 days2016: Unhealthy for Sensitive Groups 4 of 347 days2017: Good 308 of 312 days2017: Moderate 4 of 312 days2018: Good 233 of 245 days2018: Moderate 12 of 245 days2019: Good 185 of 185 days2019
  • 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 year0501001990: 90th percentile AQI 381991: 90th percentile AQI 291992: 90th percentile AQI 471993: 90th percentile AQI 461994: 90th percentile AQI 491995: 90th percentile AQI 481996: 90th percentile AQI 471997: 90th percentile AQI 481998: 90th percentile AQI 491999: 90th percentile AQI 542000: 90th percentile AQI 462001: 90th percentile AQI 502002: 90th percentile AQI 492003: 90th percentile AQI 502004: 90th percentile AQI 462005: 90th percentile AQI 502006: 90th percentile AQI 472007: 90th percentile AQI 482008: 90th percentile AQI 482009: 90th percentile AQI 472010: 90th percentile AQI 492011: 90th percentile AQI 462012: 90th percentile AQI 472013: 90th percentile AQI 452014: 90th percentile AQI 442015: 90th percentile AQI 442016: 90th percentile AQI 432017: 90th percentile AQI 422018: 90th percentile AQI 482019: 90th percentile AQI 371990: Median AQI 101991: Median AQI 141992: Median AQI 331993: Median AQI 311994: Median AQI 341995: Median AQI 341996: Median AQI 351997: Median AQI 331998: Median AQI 331999: Median AQI 352000: Median AQI 342001: Median AQI 352002: Median AQI 352003: Median AQI 352004: Median AQI 332005: Median AQI 352006: Median AQI 332007: Median AQI 332008: Median AQI 332009: Median AQI 342010: Median AQI 362011: Median AQI 342012: Median AQI 332013: Median AQI 332014: Median AQI 332015: Median AQI 332016: Median AQI 322017: Median AQI 312018: Median AQI 362019: Median AQI 291990199520002005201020152019
  • Median daily AQI
  • 90th-percentile daily AQI

Main pollutant by day, 2019

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
Ozone185100%

Year-by-year data

Annual AQI summary by year
YearDays with AQIGoodModerateUnhealthy for Sensitive GroupsUnhealthyVery UnhealthyHazardousMedian AQI90th pct.Max AQIMain pollutant
201918518500000293745Ozone
2018245233120000364893Ozone
201731230840000314277Ozone
2016347337640003243108Ozone
201536035190000334484Ozone
2014357350700003344100Ozone
2013359348110000334593Ozone
2012359340190000334793Ozone
2011354340140000344690Ozone
20103593322610003649105Ozone
20093623382310003447105Ozone
20083613342430003348140Ozone
20073513271950003348147Ozone
20063563361820003347115Ozone
20053563213320003550129Ozone
20043593382010003346115Ozone
20033443152432003550161Ozone
20023533192581003549159Ozone
20013533182870003550147Ozone
20003513351411003446166Ozone
19993272883270003554136Ozone
19983593292640003349147Ozone
19973603312360003348122Ozone
19963583381910003547140Ozone
19953563312050003448150Ozone
19943593342320003449133Ozone
1993358335230000314693Ozone
19923002771931003347151Ozone
1991565510000142958PM10
1990282800000103848PM10

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 2019

All monitored counties in New York

Source: U.S. EPA AirData, “Annual AQI by County” files for 1990–2019 (EPA download page). EPA file dates: 2026-06-26. Imported into EnviroNearby November 5, 2026. How we use this data · Report a problem