EnviroNearby

Macon County, Illinois air quality history

Daily Air Quality Index summaries from EPA monitors in Macon, Illinois, 1980–2025.

65%
Good days in 2025
44
Median daily AQI, 2025
3
Days above 100 in 2025
365
Days with an AQI in 2025 (of 365)

In 2025, EPA reported a daily Air Quality Index (AQI) for Macon, Illinois on 365 days. 237 of those days (65%) were in the Good range, and the median daily AQI was 44. That median is about the same as the typical monitored county in Illinois (median 42 across 23 counties), and higher than the typical monitored U.S. county (40). The main pollutant was fine particles (PM2.5) on 222 days. Across the years with fuller monitoring, the share of Good days fell: an average of 85% in 1980–1982 versus 59% 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%1980: Good 178 of 240 days1980: Moderate 48 of 240 days1980: Unhealthy for Sensitive Groups 13 of 240 days1980: Unhealthy 1 of 240 days19801981: Good 213 of 234 days1981: Moderate 17 of 234 days1981: Unhealthy for Sensitive Groups 4 of 234 days1982: Good 303 of 335 days1982: Moderate 29 of 335 days1982: Unhealthy for Sensitive Groups 3 of 335 days1983: Good 194 of 265 days1983: Moderate 45 of 265 days1983: Unhealthy for Sensitive Groups 25 of 265 days1983: Unhealthy 1 of 265 days1984: Good 278 of 351 days1984: Moderate 40 of 351 days1984: Unhealthy for Sensitive Groups 31 of 351 days1984: Unhealthy 2 of 351 days1985: Good 293 of 358 days1985: Moderate 54 of 358 days1985: Unhealthy for Sensitive Groups 10 of 358 days1985: Unhealthy 1 of 358 days19851986: Good 252 of 341 days1986: Moderate 75 of 341 days1986: Unhealthy for Sensitive Groups 13 of 341 days1986: Unhealthy 1 of 341 days1987: Good 285 of 358 days1987: Moderate 60 of 358 days1987: Unhealthy for Sensitive Groups 12 of 358 days1987: Unhealthy 1 of 358 days1988: Good 265 of 361 days1988: Moderate 60 of 361 days1988: Unhealthy for Sensitive Groups 27 of 361 days1988: Unhealthy 9 of 361 days1989: Good 263 of 357 days1989: Moderate 80 of 357 days1989: Unhealthy for Sensitive Groups 11 of 357 days1989: Unhealthy 3 of 357 days1990: Good 290 of 361 days1990: Moderate 61 of 361 days1990: Unhealthy for Sensitive Groups 10 of 361 days19901991: Good 289 of 348 days1991: Moderate 46 of 348 days1991: Unhealthy for Sensitive Groups 9 of 348 days1991: Unhealthy 4 of 348 days1992: Good 298 of 360 days1992: Moderate 53 of 360 days1992: Unhealthy for Sensitive Groups 8 of 360 days1992: Unhealthy 1 of 360 days1993: Good 328 of 355 days1993: Moderate 25 of 355 days1993: Unhealthy for Sensitive Groups 2 of 355 days1994: Good 294 of 362 days1994: Moderate 53 of 362 days1994: Unhealthy for Sensitive Groups 14 of 362 days1994: Unhealthy 1 of 362 days1995: Good 299 of 363 days1995: Moderate 45 of 363 days1995: Unhealthy for Sensitive Groups 17 of 363 days1995: Unhealthy 2 of 363 days19951996: Good 294 of 362 days1996: Moderate 48 of 362 days1996: Unhealthy for Sensitive Groups 15 of 362 days1996: Unhealthy 5 of 362 days1997: Good 304 of 364 days1997: Moderate 49 of 364 days1997: Unhealthy for Sensitive Groups 11 of 364 days1998: Good 284 of 365 days1998: Moderate 68 of 365 days1998: Unhealthy for Sensitive Groups 13 of 365 days1999: Good 259 of 350 days1999: Moderate 77 of 350 days1999: Unhealthy for Sensitive Groups 10 of 350 days1999: Unhealthy 4 of 350 days2000: Good 251 of 366 days2000: Moderate 110 of 366 days2000: Unhealthy for Sensitive Groups 5 of 366 days20002001: Good 240 of 364 days2001: Moderate 117 of 364 days2001: Unhealthy for Sensitive Groups 7 of 364 days2002: Good 239 of 363 days2002: Moderate 102 of 363 days2002: Unhealthy for Sensitive Groups 20 of 363 days2002: Unhealthy 2 of 363 days2003: Good 246 of 365 days2003: Moderate 113 of 365 days2003: Unhealthy for Sensitive Groups 6 of 365 days2004: Good 301 of 365 days2004: Moderate 64 of 365 days2005: Good 248 of 365 days2005: Moderate 98 of 365 days2005: Unhealthy for Sensitive Groups 19 of 365 days20052006: Good 260 of 363 days2006: Moderate 97 of 363 days2006: Unhealthy for Sensitive Groups 6 of 363 days2007: Good 132 of 365 days2007: Moderate 221 of 365 days2007: Unhealthy for Sensitive Groups 12 of 365 days2008: Good 194 of 363 days2008: Moderate 169 of 363 days2009: Good 162 of 365 days2009: Moderate 203 of 365 days2010: Good 167 of 365 days2010: Moderate 198 of 365 days20102011: Good 119 of 365 days2011: Moderate 241 of 365 days2011: Unhealthy for Sensitive Groups 4 of 365 days2011: Unhealthy 1 of 365 days2012: Good 164 of 366 days2012: Moderate 192 of 366 days2012: Unhealthy for Sensitive Groups 10 of 366 days2013: Good 226 of 365 days2013: Moderate 139 of 365 days2014: Good 214 of 365 days2014: Moderate 151 of 365 days2015: Good 228 of 365 days2015: Moderate 137 of 365 days20152016: Good 201 of 365 days2016: Moderate 164 of 365 days2017: Good 214 of 363 days2017: Moderate 146 of 363 days2017: Unhealthy for Sensitive Groups 3 of 363 days2018: Good 162 of 365 days2018: Moderate 200 of 365 days2018: Unhealthy for Sensitive Groups 3 of 365 days2019: Good 176 of 364 days2019: Moderate 188 of 364 days2020: Good 214 of 362 days2020: Moderate 148 of 362 days20202021: Good 179 of 361 days2021: Moderate 179 of 361 days2021: Unhealthy for Sensitive Groups 3 of 361 days2022: Good 209 of 365 days2022: Moderate 154 of 365 days2022: Unhealthy for Sensitive Groups 2 of 365 days2023: Good 171 of 365 days2023: Moderate 178 of 365 days2023: Unhealthy for Sensitive Groups 14 of 365 days2023: Unhealthy 1 of 365 days2023: Very Unhealthy 1 of 365 days2024: Good 238 of 366 days2024: Moderate 127 of 366 days2024: Unhealthy for Sensitive Groups 1 of 366 days2025: Good 237 of 365 days2025: Moderate 125 of 365 days2025: Unhealthy for Sensitive Groups 3 of 365 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 year0501001980: 90th percentile AQI 871981: 90th percentile AQI 501982: 90th percentile AQI 501983: 90th percentile AQI 1001984: 90th percentile AQI 1001985: 90th percentile AQI 711986: 90th percentile AQI 741987: 90th percentile AQI 691988: 90th percentile AQI 1001989: 90th percentile AQI 771990: 90th percentile AQI 671991: 90th percentile AQI 671992: 90th percentile AQI 641993: 90th percentile AQI 491994: 90th percentile AQI 711995: 90th percentile AQI 771996: 90th percentile AQI 771997: 90th percentile AQI 671998: 90th percentile AQI 771999: 90th percentile AQI 772000: 90th percentile AQI 732001: 90th percentile AQI 742002: 90th percentile AQI 802003: 90th percentile AQI 742004: 90th percentile AQI 592005: 90th percentile AQI 872006: 90th percentile AQI 702007: 90th percentile AQI 802008: 90th percentile AQI 672009: 90th percentile AQI 702010: 90th percentile AQI 742011: 90th percentile AQI 712012: 90th percentile AQI 742013: 90th percentile AQI 632014: 90th percentile AQI 672015: 90th percentile AQI 642016: 90th percentile AQI 602017: 90th percentile AQI 612018: 90th percentile AQI 672019: 90th percentile AQI 642020: 90th percentile AQI 602021: 90th percentile AQI 672022: 90th percentile AQI 622023: 90th percentile AQI 762024: 90th percentile AQI 592025: 90th percentile AQI 641980: Median AQI 371981: Median AQI 311982: Median AQI 271983: Median AQI 351984: Median AQI 331985: Median AQI 351986: Median AQI 371987: Median AQI 341988: Median AQI 351989: Median AQI 371990: Median AQI 361991: Median AQI 341992: Median AQI 341993: Median AQI 301994: Median AQI 331995: Median AQI 311996: Median AQI 341997: Median AQI 321998: Median AQI 341999: Median AQI 372000: Median AQI 422001: Median AQI 412002: Median AQI 412003: Median AQI 412004: Median AQI 352005: Median AQI 392006: Median AQI 382007: Median AQI 552008: Median AQI 472009: Median AQI 522010: Median AQI 522011: Median AQI 552012: Median AQI 522013: Median AQI 442014: Median AQI 452015: Median AQI 442016: Median AQI 492017: Median AQI 472018: Median AQI 522019: Median AQI 512020: Median AQI 462021: Median AQI 512022: Median AQI 462023: Median AQI 512024: Median AQI 432025: Median AQI 441980198519901995200020052010201520202025
  • 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
Fine particles (PM2.5)22261%
Ozone14339%

Year-by-year data

Annual AQI summary by year
YearDays with AQIGoodModerateUnhealthy for Sensitive GroupsUnhealthyVery UnhealthyHazardousMedian AQI90th pct.Max AQIMain pollutant
202536523712530004464141PM2.5
202436623812710004359101PM2.5
2023365171178141105176287PM2.5
202236520915420004662115PM2.5
202136117917930005167112PM2.5
20203622141480000466090PM2.5
20193641761880000516493PM2.5
201836516220030005267126PM2.5
201736321414630004761108PM2.5
20163652011640000496097PM2.5
201536522813700004464100PM2.5
20143652141510000456790PM2.5
20133652261390000446388PM2.5
2012366164192100005274126PM2.5
201136511924141005571161PM2.5
20103651671980000527499PM2.5
20093651622030000527097PM2.5
20083631941690000476797PM2.5
2007365132221120005580129PM2.5
20063632609760003870129Ozone
200536524898190003987136Ozone
2004365301640000355988Ozone
200336524611360004174129Ozone
2002363239102202004180172Ozone
200136424011770004174119Ozone
200036625111050004273147Ozone
199935025977104003777164Ozone
199836528468130003477143Ozone
199736430449110003267136Ozone
199636229448155003477182Ozone
199536329945172003177177Ozone
199436229453141003371161Ozone
19933553282520003049143Ozone
19923602985381003464156Ozone
19913482894694003467166Ozone
199036129061100003667150Ozone
198935726380113003777164Ozone
1988361265602790035100174Ozone
198735828560121003469156Ozone
198634125275131003774156Ozone
198535829354101003571164Ozone
1984351278403120033100164Ozone
1983265194452510035100154Ozone
19823353032930002750105Ozone
19812342131740003150122Ozone
198024017848131003787151Ozone

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 Illinois with a similar median AQI in 2025

All monitored counties in Illinois

Source: U.S. EPA AirData, “Annual AQI by County” files for 1980–2025 (EPA download page). EPA file dates: 2026-06-26. Imported into EnviroNearby November 5, 2026. How we use this data · Report a problem