EnviroNearby

Clark County, Arkansas air quality history

Daily Air Quality Index summaries from EPA monitors in Clark, Arkansas, 1990–2025.

97%
Good days in 2025
34
Median daily AQI, 2025
0
Days above 100 in 2025
363
Days with an AQI in 2025 (of 365)

In 2025, EPA reported a daily Air Quality Index (AQI) for Clark, Arkansas on 363 days. 351 of those days (97%) were in the Good range, and the median daily AQI was 34. That median is lower than the typical monitored county in Arkansas (median 46 across 11 counties), and lower than the typical monitored U.S. county (40). The main pollutant was ozone on 363 days. Across the years with fuller monitoring, the share of Good days rose: an average of 83% in 1990–1992 versus 94% 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%1990: Good 286 of 361 days1990: Moderate 65 of 361 days1990: Unhealthy for Sensitive Groups 10 of 361 days19901991: Good 300 of 363 days1991: Moderate 54 of 363 days1991: Unhealthy for Sensitive Groups 9 of 363 days1992: Good 307 of 357 days1992: Moderate 47 of 357 days1992: Unhealthy for Sensitive Groups 3 of 357 days1993: Good 288 of 351 days1993: Moderate 56 of 351 days1993: Unhealthy for Sensitive Groups 7 of 351 days1994: Good 291 of 360 days1994: Moderate 56 of 360 days1994: Unhealthy for Sensitive Groups 13 of 360 days1995: Good 198 of 266 days1995: Moderate 55 of 266 days1995: Unhealthy for Sensitive Groups 12 of 266 days1995: Unhealthy 1 of 266 days19951996: Good 172 of 211 days1996: Moderate 34 of 211 days1996: Unhealthy for Sensitive Groups 5 of 211 days1997: Good 280 of 362 days1997: Moderate 72 of 362 days1997: Unhealthy for Sensitive Groups 10 of 362 days1998: Good 250 of 358 days1998: Moderate 80 of 358 days1998: Unhealthy for Sensitive Groups 25 of 358 days1998: Unhealthy 3 of 358 days1999: Good 235 of 347 days1999: Moderate 83 of 347 days1999: Unhealthy for Sensitive Groups 23 of 347 days1999: Unhealthy 6 of 347 days2000: Good 265 of 347 days2000: Moderate 57 of 347 days2000: Unhealthy for Sensitive Groups 25 of 347 days20002001: Good 294 of 362 days2001: Moderate 60 of 362 days2001: Unhealthy for Sensitive Groups 8 of 362 days2002: Good 307 of 364 days2002: Moderate 42 of 364 days2002: Unhealthy for Sensitive Groups 12 of 364 days2002: Unhealthy 3 of 364 days2003: Good 242 of 282 days2003: Moderate 37 of 282 days2003: Unhealthy for Sensitive Groups 3 of 282 days2004: Good 310 of 348 days2004: Moderate 36 of 348 days2004: Unhealthy for Sensitive Groups 1 of 348 days2004: Unhealthy 1 of 348 days2005: Good 258 of 344 days2005: Moderate 78 of 344 days2005: Unhealthy for Sensitive Groups 8 of 344 days20052006: Good 300 of 345 days2006: Moderate 45 of 345 days2007: Good 323 of 358 days2007: Moderate 33 of 358 days2007: Unhealthy for Sensitive Groups 2 of 358 days2008: Good 324 of 343 days2008: Moderate 19 of 343 days2009: Good 334 of 345 days2009: Moderate 11 of 345 days2010: Good 310 of 359 days2010: Moderate 45 of 359 days2010: Unhealthy for Sensitive Groups 4 of 359 days20102011: Good 249 of 270 days2011: Moderate 21 of 270 days2012: Good 274 of 309 days2012: Moderate 34 of 309 days2012: Unhealthy for Sensitive Groups 1 of 309 days2013: Good 298 of 318 days2013: Moderate 19 of 318 days2013: Unhealthy for Sensitive Groups 1 of 318 days2014: Good 342 of 352 days2014: Moderate 10 of 352 days2015: Good 305 of 320 days2015: Moderate 15 of 320 days20152016: Good 351 of 355 days2016: Moderate 4 of 355 days2017: Good 345 of 358 days2017: Moderate 13 of 358 days2018: Good 342 of 361 days2018: Moderate 19 of 361 days2019: Good 347 of 355 days2019: Moderate 8 of 355 days2020: Good 341 of 342 days2020: Moderate 1 of 342 days20202021: Good 328 of 338 days2021: Moderate 10 of 338 days2022: Good 350 of 363 days2022: Moderate 13 of 363 days2023: Good 321 of 351 days2023: Moderate 30 of 351 days2024: Good 336 of 360 days2024: Moderate 24 of 360 days2025: Good 351 of 363 days2025: Moderate 12 of 363 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 year0501001990: 90th percentile AQI 771991: 90th percentile AQI 641992: 90th percentile AQI 581993: 90th percentile AQI 711994: 90th percentile AQI 711995: 90th percentile AQI 871996: 90th percentile AQI 641997: 90th percentile AQI 711998: 90th percentile AQI 931999: 90th percentile AQI 932000: 90th percentile AQI 902001: 90th percentile AQI 712002: 90th percentile AQI 642003: 90th percentile AQI 582004: 90th percentile AQI 542005: 90th percentile AQI 772006: 90th percentile AQI 612007: 90th percentile AQI 502008: 90th percentile AQI 472009: 90th percentile AQI 442010: 90th percentile AQI 582011: 90th percentile AQI 492012: 90th percentile AQI 542013: 90th percentile AQI 472014: 90th percentile AQI 452015: 90th percentile AQI 452016: 90th percentile AQI 452017: 90th percentile AQI 452018: 90th percentile AQI 462019: 90th percentile AQI 462020: 90th percentile AQI 402021: 90th percentile AQI 452022: 90th percentile AQI 462023: 90th percentile AQI 492024: 90th percentile AQI 482025: 90th percentile AQI 461990: Median AQI 391991: Median AQI 371992: Median AQI 381993: Median AQI 371994: Median AQI 361995: Median AQI 421996: Median AQI 361997: Median AQI 371998: Median AQI 401999: Median AQI 412000: Median AQI 392001: Median AQI 402002: Median AQI 362003: Median AQI 352004: Median AQI 332005: Median AQI 402006: Median AQI 352007: Median AQI 332008: Median AQI 312009: Median AQI 322010: Median AQI 352011: Median AQI 352012: Median AQI 352013: Median AQI 332014: Median AQI 332015: Median AQI 332016: Median AQI 342017: Median AQI 342018: Median AQI 312019: Median AQI 322020: Median AQI 292021: Median AQI 322022: Median AQI 352023: Median AQI 352024: Median AQI 352025: Median AQI 3419901995200020052010201520202025
  • 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
Ozone363100%

Year-by-year data

Annual AQI summary by year
YearDays with AQIGoodModerateUnhealthy for Sensitive GroupsUnhealthyVery UnhealthyHazardousMedian AQI90th pct.Max AQIMain pollutant
2025363351120000344684Ozone
2024360336240000354893Ozone
2023351321300000354987Ozone
2022363350130000354690Ozone
2021338328100000324590Ozone
202034234110000294067Ozone
201935534780000324667Ozone
2018361342190000314687Ozone
2017358345130000344574Ozone
201635535140000344554Ozone
2015320305150000334587Ozone
2014352342100000334590Ozone
20133182981910003347112Ozone
20123092743410003554133Ozone
20112702492100003549100Ozone
20103593104540003558126Ozone
2009345334110000324487Ozone
2008343324190000314784Ozone
20073583233320003350129Ozone
20063453004500003561100Ozone
20053442587880004077119Ozone
20043483103611003354154Ozone
20032822423730003558126Ozone
200236430742123003664161Ozone
20013622946080004071133Ozone
200034726557250003990147Ozone
199934723583236004193174Ozone
199835825080253004093164Ozone
199736228072100003771140Ozone
19962111723450003664140Ozone
199526619855121004287151Ozone
199436029156130003671147Ozone
19933512885670003771126Ozone
19923573074730003858122Ozone
19913633005490003764133Ozone
199036128665100003977143Ozone

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 Arkansas with a similar median AQI in 2025

All monitored counties in Arkansas

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