EnviroNearby

Lee County, Iowa air quality history

Daily Air Quality Index summaries from EPA monitors in Lee, Iowa, 2001–2023.

67%
Good days in 2019
39
Median daily AQI, 2019
0
Days above 100 in 2019
120
Days with an AQI in 2019 (of 365)

In 2019, EPA reported a daily Air Quality Index (AQI) for Lee, Iowa on 120 days. 80 of those days (67%) were in the Good range, and the median daily AQI was 39. That median is lower than the typical monitored county in Iowa (median 42 across 14 counties), and about the same as the typical monitored U.S. county (41). The main pollutant was fine particles (PM2.5) on 120 days.

EPA did not report an AQI for every day of 2019 here (120 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.

The most recent year with data for this county is 2023; EPA's files for 2024–2025 contain no row for it, which usually means its monitors stopped reporting.

Years with fewer than 120 monitored days (2016, 2017, 2020, 2021, 2022, 2023…) are shown in the table but left out of comparisons and trend statements.

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%2001: Good 24 of 24 days20012002: Good 95 of 95 days2003: Good 115 of 115 days20032004: Good 116 of 118 days2004: Moderate 2 of 118 days2005: Good 118 of 120 days2005: Moderate 2 of 120 days20052006: Good 116 of 116 days2007: Good 40 of 118 days2007: Moderate 78 of 118 days20072008: Good 44 of 118 days2008: Moderate 74 of 118 days2009: Good 57 of 120 days2009: Moderate 63 of 120 days20092010: Good 51 of 115 days2010: Moderate 62 of 115 days2010: Unhealthy for Sensitive Groups 2 of 115 days2011: Good 49 of 117 days2011: Moderate 68 of 117 days20112012: Good 49 of 111 days2012: Moderate 62 of 111 days2013: Good 50 of 110 days2013: Moderate 60 of 110 days20132014: Good 62 of 121 days2014: Moderate 59 of 121 days2015: Good 81 of 118 days2015: Moderate 37 of 118 days20152016: Good 71 of 113 days2016: Moderate 42 of 113 days2017: Good 71 of 111 days2017: Moderate 40 of 111 days20172018: Good 70 of 121 days2018: Moderate 51 of 121 days2019: Good 80 of 120 days2019: Moderate 40 of 120 days20192020: Good 83 of 118 days2020: Moderate 35 of 118 days2021: Good 63 of 101 days2021: Moderate 38 of 101 days20212022: Good 73 of 106 days2022: Moderate 33 of 106 days2023: Good 36 of 60 days2023: Moderate 24 of 60 days2023
  • 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 year0501002001: 90th percentile AQI 292002: 90th percentile AQI 312003: 90th percentile AQI 342004: 90th percentile AQI 342005: 90th percentile AQI 332006: 90th percentile AQI 342007: 90th percentile AQI 742008: 90th percentile AQI 692009: 90th percentile AQI 672010: 90th percentile AQI 712011: 90th percentile AQI 712012: 90th percentile AQI 712013: 90th percentile AQI 692014: 90th percentile AQI 682015: 90th percentile AQI 582016: 90th percentile AQI 602017: 90th percentile AQI 582018: 90th percentile AQI 612019: 90th percentile AQI 622020: 90th percentile AQI 582021: 90th percentile AQI 632022: 90th percentile AQI 572023: 90th percentile AQI 642001: Median AQI 202002: Median AQI 192003: Median AQI 212004: Median AQI 192005: Median AQI 192006: Median AQI 202007: Median AQI 562008: Median AQI 532009: Median AQI 522010: Median AQI 532011: Median AQI 522012: Median AQI 522013: Median AQI 522014: Median AQI 482015: Median AQI 442016: Median AQI 422017: Median AQI 432018: Median AQI 452019: Median AQI 392020: Median AQI 402021: Median AQI 422022: Median AQI 412023: Median AQI 47200120032005200720092011201320152017201920212023
  • Median daily AQI
  • 90th-percentile daily AQI

Main pollutant by day, 2019

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)120100%

Year-by-year data

Annual AQI summary by year
YearDays with AQIGoodModerateUnhealthy for Sensitive GroupsUnhealthyVery UnhealthyHazardousMedian AQI90th pct.Max AQIMain pollutant
20236036240000476497PM2.5
202210673330000415787PM2.5
202110163380000426373PM2.5
202011883350000405876PM2.5
201912080400000396273PM2.5
201812170510000456178PM2.5
201711171400000435869PM2.5
201611371420000426074PM2.5
201511881370000445884PM2.5
201412162590000486898PM2.5
201311050600000526990PM2.5
201211149620000527183PM2.5
201111749680000527183PM2.5
2010115516220005371115PM2.5
200912057630000526792PM2.5
200811844740000536991PM2.5
200711840780000567497PM2.5
200611611600000203450PM10
200512011820000193352PM10
200411811620000193461PM10
200311511500000213448PM10
2002959500000193145PM10
2001242400000202940PM10

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.

All monitored counties in Iowa

Source: U.S. EPA AirData, “Annual AQI by County” files for 2001–2023 (EPA download page). EPA file dates: 2026-06-26. Imported into EnviroNearby November 5, 2026. How we use this data · Report a problem