EnviroNearby

Bremer County, Iowa air quality history

Daily Air Quality Index summaries from EPA monitors in Bremer, Iowa, 2000–2025.

87%
Good days in 2025
38
Median daily AQI, 2025
1
Days above 100 in 2025
241
Days with an AQI in 2025 (of 365)

In 2025, EPA reported a daily Air Quality Index (AQI) for Bremer, Iowa on 241 days. 210 of those days (87%) were in the Good range, and the median daily AQI was 38. That median is lower than the typical monitored county in Iowa (median 43.5 across 14 counties), and about the same as the typical monitored U.S. county (40). The main pollutant was ozone on 241 days. Across the years with fuller monitoring, the share of Good days rose: an average of 79% in 2000–2002 versus 84% in 2023–2025.

EPA did not report an AQI for every day of 2025 here (241 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.

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%2000: Good 168 of 213 days2000: Moderate 35 of 213 days2000: Unhealthy for Sensitive Groups 10 of 213 days20002001: Good 165 of 207 days2001: Moderate 39 of 207 days2001: Unhealthy for Sensitive Groups 2 of 207 days2001: Unhealthy 1 of 207 days2002: Good 163 of 209 days2002: Moderate 43 of 209 days2002: Unhealthy for Sensitive Groups 3 of 209 days20022003: Good 143 of 211 days2003: Moderate 65 of 211 days2003: Unhealthy for Sensitive Groups 3 of 211 days2004: Good 192 of 214 days2004: Moderate 22 of 214 days20042005: Good 149 of 199 days2005: Moderate 47 of 199 days2005: Unhealthy for Sensitive Groups 3 of 199 days2006: Good 204 of 257 days2006: Moderate 53 of 257 days20062007: Good 175 of 243 days2007: Moderate 64 of 243 days2007: Unhealthy for Sensitive Groups 3 of 243 days2007: Unhealthy 1 of 243 days2008: Good 184 of 213 days2008: Moderate 29 of 213 days20082009: Good 193 of 214 days2009: Moderate 21 of 214 days2010: Good 187 of 214 days2010: Moderate 26 of 214 days2010: Unhealthy for Sensitive Groups 1 of 214 days20102011: Good 191 of 213 days2011: Moderate 22 of 213 days2012: Good 158 of 213 days2012: Moderate 53 of 213 days2012: Unhealthy for Sensitive Groups 2 of 213 days20122013: Good 197 of 210 days2013: Moderate 13 of 210 days2014: Good 195 of 212 days2014: Moderate 17 of 212 days20142015: Good 200 of 214 days2015: Moderate 14 of 214 days2016: Good 196 of 213 days2016: Moderate 17 of 213 days20162017: Good 224 of 241 days2017: Moderate 17 of 241 days2018: Good 224 of 245 days2018: Moderate 19 of 245 days2018: Unhealthy for Sensitive Groups 2 of 245 days20182019: Good 228 of 243 days2019: Moderate 15 of 243 days2020: Good 232 of 244 days2020: Moderate 12 of 244 days20202021: Good 223 of 244 days2021: Moderate 21 of 244 days2022: Good 235 of 243 days2022: Moderate 8 of 243 days20222023: Good 180 of 235 days2023: Moderate 45 of 235 days2023: Unhealthy for Sensitive Groups 9 of 235 days2023: Unhealthy 1 of 235 days2024: Good 207 of 234 days2024: Moderate 27 of 234 days20242025: Good 210 of 241 days2025: Moderate 30 of 241 days2025: Unhealthy for Sensitive Groups 1 of 241 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 year0501002000: 90th percentile AQI 772001: 90th percentile AQI 672002: 90th percentile AQI 712003: 90th percentile AQI 742004: 90th percentile AQI 512005: 90th percentile AQI 742006: 90th percentile AQI 622007: 90th percentile AQI 672008: 90th percentile AQI 542009: 90th percentile AQI 502010: 90th percentile AQI 542011: 90th percentile AQI 512012: 90th percentile AQI 742013: 90th percentile AQI 492014: 90th percentile AQI 482015: 90th percentile AQI 482016: 90th percentile AQI 482017: 90th percentile AQI 492018: 90th percentile AQI 502019: 90th percentile AQI 462020: 90th percentile AQI 452021: 90th percentile AQI 492022: 90th percentile AQI 472023: 90th percentile AQI 742024: 90th percentile AQI 542025: 90th percentile AQI 542000: Median AQI 382001: Median AQI 402002: Median AQI 422003: Median AQI 442004: Median AQI 382005: Median AQI 432006: Median AQI 422007: Median AQI 432008: Median AQI 402009: Median AQI 362010: Median AQI 382011: Median AQI 402012: Median AQI 432013: Median AQI 382014: Median AQI 372015: Median AQI 362016: Median AQI 332017: Median AQI 362018: Median AQI 372019: Median AQI 372020: Median AQI 352021: Median AQI 402022: Median AQI 372023: Median AQI 422024: Median AQI 402025: Median AQI 3820002002200420062008201020122014201620182020202220242025
  • 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
Ozone241100%

Year-by-year data

Annual AQI summary by year
YearDays with AQIGoodModerateUnhealthy for Sensitive GroupsUnhealthyVery UnhealthyHazardousMedian AQI90th pct.Max AQIMain pollutant
20252412103010003854115Ozone
2024234207270000405474Ozone
20232351804591004274151Ozone
202224323580000374767Ozone
2021244223210000404990Ozone
2020244232120000354587Ozone
2019243228150000374690Ozone
20182452241920003750112Ozone
2017241224170000364993Ozone
2016213196170000334880Ozone
2015214200140000364880Ozone
2014212195170000374887Ozone
2013210197130000384977Ozone
20122131585320004374105Ozone
2011213191220000405197Ozone
20102141872610003854108Ozone
2009214193210000365077Ozone
2008213184290000405487Ozone
20072431756431004367151Ozone
2006257204530000426297Ozone
20051991494730004374126Ozone
2004214192220000385184Ozone
20032111436530004474101Ozone
20022091634330004271129Ozone
20012071653921004067154Ozone
200021316835100003877143Ozone

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 Iowa with a similar median AQI in 2025

All monitored counties in Iowa

Source: U.S. EPA AirData, “Annual AQI by County” files for 2000–2025 (EPA download page). EPA file dates: 2026-06-26. Imported into EnviroNearby November 5, 2026. How we use this data · Report a problem