EnviroNearby

Macoupin County, Illinois air quality history

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

92%
Good days in 2025
34
Median daily AQI, 2025
1
Days above 100 in 2025
364
Days with an AQI in 2025 (of 365)

In 2025, EPA reported a daily Air Quality Index (AQI) for Macoupin, Illinois on 364 days. 334 of those days (92%) were in the Good range, and the median daily AQI was 34. That median is lower than the typical monitored county in Illinois (median 42 across 23 counties), and lower than the typical monitored U.S. county (40). The main pollutant was ozone on 240 days. Across the years with fuller monitoring, the share of Good days rose: an average of 82% in 1980–1982 versus 90% 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 166 of 215 days1980: Moderate 30 of 215 days1980: Unhealthy for Sensitive Groups 12 of 215 days1980: Unhealthy 6 of 215 days1980: Very Unhealthy 1 of 215 days19801981: Good 122 of 152 days1981: Moderate 21 of 152 days1981: Unhealthy for Sensitive Groups 6 of 152 days1981: Unhealthy 3 of 152 days1982: Good 278 of 319 days1982: Moderate 35 of 319 days1982: Unhealthy for Sensitive Groups 6 of 319 days1983: Good 284 of 354 days1983: Moderate 41 of 354 days1983: Unhealthy for Sensitive Groups 24 of 354 days1983: Unhealthy 5 of 354 days1984: Good 267 of 348 days1984: Moderate 53 of 348 days1984: Unhealthy for Sensitive Groups 22 of 348 days1984: Unhealthy 6 of 348 days1985: Good 260 of 348 days1985: Moderate 66 of 348 days1985: Unhealthy for Sensitive Groups 17 of 348 days1985: Unhealthy 5 of 348 days19851986: Good 257 of 335 days1986: Moderate 57 of 335 days1986: Unhealthy for Sensitive Groups 16 of 335 days1986: Unhealthy 5 of 335 days1987: Good 252 of 358 days1987: Moderate 67 of 358 days1987: Unhealthy for Sensitive Groups 33 of 358 days1987: Unhealthy 5 of 358 days1987: Very Unhealthy 1 of 358 days1988: Good 224 of 352 days1988: Moderate 63 of 352 days1988: Unhealthy for Sensitive Groups 39 of 352 days1988: Unhealthy 24 of 352 days1988: Very Unhealthy 2 of 352 days1989: Good 258 of 347 days1989: Moderate 67 of 347 days1989: Unhealthy for Sensitive Groups 20 of 347 days1989: Unhealthy 2 of 347 days1990: Good 266 of 335 days1990: Moderate 45 of 335 days1990: Unhealthy for Sensitive Groups 17 of 335 days1990: Unhealthy 7 of 335 days19901991: Good 318 of 364 days1991: Moderate 36 of 364 days1991: Unhealthy for Sensitive Groups 9 of 364 days1991: Unhealthy 1 of 364 days1992: Good 308 of 361 days1992: Moderate 43 of 361 days1992: Unhealthy for Sensitive Groups 9 of 361 days1992: Unhealthy 1 of 361 days1993: Good 322 of 361 days1993: Moderate 32 of 361 days1993: Unhealthy for Sensitive Groups 6 of 361 days1993: Unhealthy 1 of 361 days1994: Good 283 of 360 days1994: Moderate 49 of 360 days1994: Unhealthy for Sensitive Groups 26 of 360 days1994: Unhealthy 2 of 360 days1995: Good 302 of 365 days1995: Moderate 41 of 365 days1995: Unhealthy for Sensitive Groups 20 of 365 days1995: Unhealthy 2 of 365 days19951996: Good 305 of 364 days1996: Moderate 40 of 364 days1996: Unhealthy for Sensitive Groups 14 of 364 days1996: Unhealthy 5 of 364 days1997: Good 297 of 364 days1997: Moderate 54 of 364 days1997: Unhealthy for Sensitive Groups 12 of 364 days1997: Unhealthy 1 of 364 days1998: Good 285 of 363 days1998: Moderate 60 of 363 days1998: Unhealthy for Sensitive Groups 18 of 363 days1999: Good 254 of 350 days1999: Moderate 79 of 350 days1999: Unhealthy for Sensitive Groups 14 of 350 days1999: Unhealthy 3 of 350 days2000: Good 286 of 362 days2000: Moderate 59 of 362 days2000: Unhealthy for Sensitive Groups 14 of 362 days2000: Unhealthy 3 of 362 days20002001: Good 279 of 357 days2001: Moderate 67 of 357 days2001: Unhealthy for Sensitive Groups 10 of 357 days2001: Unhealthy 1 of 357 days2002: Good 293 of 363 days2002: Moderate 51 of 363 days2002: Unhealthy for Sensitive Groups 16 of 363 days2002: Unhealthy 3 of 363 days2003: Good 287 of 361 days2003: Moderate 60 of 361 days2003: Unhealthy for Sensitive Groups 13 of 361 days2003: Unhealthy 1 of 361 days2004: Good 316 of 359 days2004: Moderate 42 of 359 days2004: Unhealthy for Sensitive Groups 1 of 359 days2005: Good 277 of 365 days2005: Moderate 75 of 365 days2005: Unhealthy for Sensitive Groups 12 of 365 days2005: Unhealthy 1 of 365 days20052006: Good 288 of 339 days2006: Moderate 49 of 339 days2006: Unhealthy for Sensitive Groups 2 of 339 days2007: Good 314 of 364 days2007: Moderate 41 of 364 days2007: Unhealthy for Sensitive Groups 8 of 364 days2007: Unhealthy 1 of 364 days2008: Good 326 of 351 days2008: Moderate 24 of 351 days2008: Unhealthy for Sensitive Groups 1 of 351 days2009: Good 314 of 343 days2009: Moderate 29 of 343 days2010: Good 321 of 360 days2010: Moderate 35 of 360 days2010: Unhealthy for Sensitive Groups 4 of 360 days20102011: Good 309 of 363 days2011: Moderate 48 of 363 days2011: Unhealthy for Sensitive Groups 5 of 363 days2011: Unhealthy 1 of 363 days2012: Good 282 of 361 days2012: Moderate 68 of 361 days2012: Unhealthy for Sensitive Groups 11 of 361 days2013: Good 259 of 294 days2013: Moderate 35 of 294 days2014: Good 192 of 214 days2014: Moderate 22 of 214 days2015: Good 195 of 213 days2015: Moderate 18 of 213 days20152016: Good 182 of 203 days2016: Moderate 21 of 203 days2017: Good 218 of 244 days2017: Moderate 26 of 244 days2018: Good 300 of 333 days2018: Moderate 30 of 333 days2018: Unhealthy for Sensitive Groups 3 of 333 days2019: Good 340 of 357 days2019: Moderate 17 of 357 days2020: Good 346 of 364 days2020: Moderate 18 of 364 days20202021: Good 339 of 358 days2021: Moderate 19 of 358 days2022: Good 352 of 363 days2022: Moderate 9 of 363 days2022: Unhealthy for Sensitive Groups 2 of 363 days2023: Good 310 of 365 days2023: Moderate 45 of 365 days2023: Unhealthy for Sensitive Groups 10 of 365 days2024: Good 342 of 366 days2024: Moderate 23 of 366 days2024: Unhealthy for Sensitive Groups 1 of 366 days2025: Good 334 of 364 days2025: Moderate 29 of 364 days2025: Unhealthy for Sensitive Groups 1 of 364 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 year0501001501980: 90th percentile AQI 931981: 90th percentile AQI 801982: 90th percentile AQI 611983: 90th percentile AQI 901984: 90th percentile AQI 971985: 90th percentile AQI 901986: 90th percentile AQI 871987: 90th percentile AQI 1011988: 90th percentile AQI 1361989: 90th percentile AQI 901990: 90th percentile AQI 841991: 90th percentile AQI 581992: 90th percentile AQI 641993: 90th percentile AQI 511994: 90th percentile AQI 871995: 90th percentile AQI 801996: 90th percentile AQI 741997: 90th percentile AQI 711998: 90th percentile AQI 741999: 90th percentile AQI 802000: 90th percentile AQI 742001: 90th percentile AQI 772002: 90th percentile AQI 802003: 90th percentile AQI 712004: 90th percentile AQI 542005: 90th percentile AQI 842006: 90th percentile AQI 612007: 90th percentile AQI 582008: 90th percentile AQI 492009: 90th percentile AQI 502010: 90th percentile AQI 512011: 90th percentile AQI 612012: 90th percentile AQI 712013: 90th percentile AQI 512014: 90th percentile AQI 512015: 90th percentile AQI 492016: 90th percentile AQI 512017: 90th percentile AQI 512018: 90th percentile AQI 502019: 90th percentile AQI 472020: 90th percentile AQI 452021: 90th percentile AQI 482022: 90th percentile AQI 452023: 90th percentile AQI 612024: 90th percentile AQI 472025: 90th percentile AQI 491980: Median AQI 341981: Median AQI 381982: Median AQI 331983: Median AQI 331984: Median AQI 351985: Median AQI 391986: Median AQI 361987: Median AQI 381988: Median AQI 411989: Median AQI 371990: Median AQI 341991: Median AQI 341992: Median AQI 331993: Median AQI 331994: Median AQI 341995: Median AQI 331996: Median AQI 361997: Median AQI 361998: Median AQI 361999: Median AQI 392000: Median AQI 382001: Median AQI 372002: Median AQI 342003: Median AQI 362004: Median AQI 342005: Median AQI 372006: Median AQI 342007: Median AQI 342008: Median AQI 332009: Median AQI 342010: Median AQI 372011: Median AQI 382012: Median AQI 362013: Median AQI 392014: Median AQI 382015: Median AQI 382016: Median AQI 392017: Median AQI 402018: Median AQI 362019: Median AQI 332020: Median AQI 312021: Median AQI 312022: Median AQI 332023: Median AQI 372024: Median AQI 352025: Median AQI 341980198519901995200020052010201520202025
  • 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
Ozone24066%
Nitrogen dioxide (NO₂)12434%

Year-by-year data

Annual AQI summary by year
YearDays with AQIGoodModerateUnhealthy for Sensitive GroupsUnhealthyVery UnhealthyHazardousMedian AQI90th pct.Max AQIMain pollutant
20253643342910003449105Ozone
20243663422310003547105Ozone
202336531045100003761129Ozone
2022363352920003345108Ozone
2021358339190000314893Ozone
2020364346180000314593Ozone
2019357340170000334787Ozone
20183333003030003650115Ozone
2017244218260000405193Ozone
2016203182210000395197Ozone
2015213195180000384990Ozone
2014214192220000385193Ozone
2013294259350000395187Ozone
201236128268110003671122Ozone
20113633094851003861151Ozone
20103603213540003751119Ozone
2009343314290000345087Ozone
20083513262410003349101Ozone
20073643144181003458164Ozone
20063392884920003461108Ozone
200536527775121003784151Ozone
20043593164210003454133Ozone
200336128760131003671161Ozone
200236329351163003480159Ozone
200135727967101003777164Ozone
200036228659143003874164Ozone
199935025479143003980166Ozone
199836328560180003674150Ozone
199736429754121003671156Ozone
199636430540145003674185Ozone
199536530241202003380197Ozone
199436028349262003487159Ozone
19933613223261003351179Ozone
19923613084391003364166Ozone
19913643183691003458195Ozone
199033526645177003484192Ozone
198934725867202003790169Ozone
19883522246339242041136227Ozone
1987358252673351038101201Ozone
198633525757165003687197Ozone
198534826066175003990187Ozone
198434826753226003597172Ozone
198335428441245003390197Ozone
19823192783560003361143Ozone
19811521222163003880166Ozone
198021516630126103493201Ozone

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