EnviroNearby

Codington County, South Dakota air quality history

Daily Air Quality Index summaries from EPA monitors in Codington, South Dakota, 2003–2025.

78%
Good days in 2025
35
Median daily AQI, 2025
4
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 Codington, South Dakota on 363 days. 283 of those days (78%) were in the Good range, and the median daily AQI was 35. That median is about the same as the typical monitored county in South Dakota (median 35.5 across 10 counties), and lower than the typical monitored U.S. county (40). The main pollutant was fine particles (PM2.5) on 204 days. Across the years with fuller monitoring, the share of Good days rose: an average of 53% in 2003–2005 versus 71% 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%2003: Good 66 of 121 days2003: Moderate 55 of 121 days20032004: Good 62 of 122 days2004: Moderate 59 of 122 days2004: Unhealthy for Sensitive Groups 1 of 122 days2005: Good 66 of 123 days2005: Moderate 57 of 123 days20052006: Good 275 of 340 days2006: Moderate 65 of 340 days2007: Good 307 of 360 days2007: Moderate 53 of 360 days20072008: Good 296 of 362 days2008: Moderate 65 of 362 days2008: Unhealthy 1 of 362 days2009: Good 317 of 363 days2009: Moderate 45 of 363 days2009: Unhealthy for Sensitive Groups 1 of 363 days20092010: Good 310 of 364 days2010: Moderate 54 of 364 days2011: Good 311 of 356 days2011: Moderate 44 of 356 days2011: Unhealthy for Sensitive Groups 1 of 356 days20112012: Good 151 of 357 days2012: Moderate 206 of 357 days2013: Good 198 of 361 days2013: Moderate 163 of 361 days20132014: Good 327 of 365 days2014: Moderate 38 of 365 days2015: Good 276 of 356 days2015: Moderate 79 of 356 days2015: Unhealthy for Sensitive Groups 1 of 356 days20152016: Good 295 of 366 days2016: Moderate 71 of 366 days2017: Good 276 of 364 days2017: Moderate 88 of 364 days20172018: Good 260 of 365 days2018: Moderate 104 of 365 days2018: Unhealthy for Sensitive Groups 1 of 365 days2019: Good 295 of 361 days2019: Moderate 66 of 361 days20192020: Good 293 of 366 days2020: Moderate 72 of 366 days2020: Unhealthy for Sensitive Groups 1 of 366 days2021: Good 246 of 365 days2021: Moderate 113 of 365 days2021: Unhealthy for Sensitive Groups 3 of 365 days2021: Unhealthy 2 of 365 days2021: Very Unhealthy 1 of 365 days20212022: Good 285 of 365 days2022: Moderate 79 of 365 days2022: Unhealthy for Sensitive Groups 1 of 365 days2023: Good 215 of 363 days2023: Moderate 135 of 363 days2023: Unhealthy for Sensitive Groups 12 of 363 days2023: Unhealthy 1 of 363 days20232024: Good 269 of 361 days2024: Moderate 91 of 361 days2024: Unhealthy for Sensitive Groups 1 of 361 days2025: Good 283 of 363 days2025: Moderate 76 of 363 days2025: Unhealthy for Sensitive Groups 3 of 363 days2025: Unhealthy 1 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 year0501002003: 90th percentile AQI 662004: 90th percentile AQI 642005: 90th percentile AQI 722006: 90th percentile AQI 572007: 90th percentile AQI 542008: 90th percentile AQI 552009: 90th percentile AQI 522010: 90th percentile AQI 562011: 90th percentile AQI 542012: 90th percentile AQI 652013: 90th percentile AQI 642014: 90th percentile AQI 512015: 90th percentile AQI 562016: 90th percentile AQI 542017: 90th percentile AQI 552018: 90th percentile AQI 572019: 90th percentile AQI 552020: 90th percentile AQI 552021: 90th percentile AQI 692022: 90th percentile AQI 582023: 90th percentile AQI 772024: 90th percentile AQI 582025: 90th percentile AQI 582003: Median AQI 462004: Median AQI 502005: Median AQI 482006: Median AQI 242007: Median AQI 262008: Median AQI 242009: Median AQI 222010: Median AQI 232011: Median AQI 202012: Median AQI 522013: Median AQI 482014: Median AQI 232015: Median AQI 342016: Median AQI 282017: Median AQI 392018: Median AQI 392019: Median AQI 322020: Median AQI 382021: Median AQI 432022: Median AQI 412023: Median AQI 452024: Median AQI 372025: Median AQI 35200320052007200920112013201520172019202120232025
  • 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)20456%
Ozone13036%
Coarse particles (PM10)298%

Year-by-year data

Annual AQI summary by year
YearDays with AQIGoodModerateUnhealthy for Sensitive GroupsUnhealthyVery UnhealthyHazardousMedian AQI90th pct.Max AQIMain pollutant
20253632837631003558154PM2.5
20243612699110003758102PM2.5
2023363215135121004577164PM2.5
20223652857910004158101Ozone
202136524611332104369271PM2.5
20203662937210003855101PM2.5
2019361295660000325583PM2.5
201836526010410003957103PM2.5
2017364276880000395582PM2.5
2016366295710000285473PM2.5
20153562767910003456138PM2.5
2014365327380000235187PM2.5
20133611981630000486484PM2.5
20123571512060000526592PM2.5
20113563114410002054102PM10
2010364310540000235699PM10
20093633174510002252107PM10
20083622966501002455151PM10
2007360307530000265488PM10
2006340275650000245786PM10
200512366570000487284PM2.5
2004122625910005064103PM2.5
200312166550000466683PM2.5

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 South Dakota with a similar median AQI in 2025

All monitored counties in South Dakota

Source: U.S. EPA AirData, “Annual AQI by County” files for 2003–2025 (EPA download page). EPA file dates: 2026-06-26. Imported into EnviroNearby November 5, 2026. How we use this data · Report a problem