EnviroNearby

DeKalb County, Alabama air quality history

Daily Air Quality Index summaries from EPA monitors in DeKalb, Alabama, 1990–2025.

77%
Good days in 2025
41
Median daily AQI, 2025
0
Days above 100 in 2025
365
Days with an AQI in 2025 (of 365)

In 2025, EPA reported a daily Air Quality Index (AQI) for DeKalb, Alabama on 365 days. 282 of those days (77%) were in the Good range, and the median daily AQI was 41. That median is about the same as the typical monitored county in Alabama (median 41 across 14 counties), and about the same as the typical monitored U.S. county (40). The main pollutant was ozone on 233 days. Across the years with fuller monitoring, the share of Good days held roughly steady: an average of 68% in 1990–1992 versus 70% 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 204 of 360 days1990: Moderate 89 of 360 days1990: Unhealthy for Sensitive Groups 55 of 360 days1990: Unhealthy 11 of 360 days1990: Very Unhealthy 1 of 360 days19901991: Good 249 of 342 days1991: Moderate 82 of 342 days1991: Unhealthy for Sensitive Groups 10 of 342 days1991: Unhealthy 1 of 342 days1992: Good 263 of 349 days1992: Moderate 71 of 349 days1992: Unhealthy for Sensitive Groups 13 of 349 days1992: Unhealthy 2 of 349 days1993: Good 244 of 357 days1993: Moderate 86 of 357 days1993: Unhealthy for Sensitive Groups 22 of 357 days1993: Unhealthy 5 of 357 days1994: Good 266 of 347 days1994: Moderate 70 of 347 days1994: Unhealthy for Sensitive Groups 11 of 347 days1995: Good 152 of 285 days1995: Moderate 98 of 285 days1995: Unhealthy for Sensitive Groups 28 of 285 days1995: Unhealthy 7 of 285 days19951996: Good 147 of 225 days1996: Moderate 56 of 225 days1996: Unhealthy for Sensitive Groups 16 of 225 days1996: Unhealthy 6 of 225 days1997: Good 231 of 307 days1997: Moderate 58 of 307 days1997: Unhealthy for Sensitive Groups 17 of 307 days1997: Unhealthy 1 of 307 days1998: Good 215 of 363 days1998: Moderate 84 of 363 days1998: Unhealthy for Sensitive Groups 45 of 363 days1998: Unhealthy 17 of 363 days1998: Very Unhealthy 2 of 363 days1999: Good 127 of 332 days1999: Moderate 126 of 332 days1999: Unhealthy for Sensitive Groups 60 of 332 days1999: Unhealthy 19 of 332 days2000: Good 161 of 354 days2000: Moderate 131 of 354 days2000: Unhealthy for Sensitive Groups 58 of 354 days2000: Unhealthy 4 of 354 days20002001: Good 198 of 365 days2001: Moderate 136 of 365 days2001: Unhealthy for Sensitive Groups 28 of 365 days2001: Unhealthy 3 of 365 days2002: Good 212 of 360 days2002: Moderate 121 of 360 days2002: Unhealthy for Sensitive Groups 24 of 360 days2002: Unhealthy 3 of 360 days2003: Good 208 of 361 days2003: Moderate 140 of 361 days2003: Unhealthy for Sensitive Groups 11 of 361 days2003: Unhealthy 2 of 361 days2004: Good 228 of 361 days2004: Moderate 126 of 361 days2004: Unhealthy for Sensitive Groups 7 of 361 days2005: Good 220 of 358 days2005: Moderate 130 of 358 days2005: Unhealthy for Sensitive Groups 8 of 358 days20052006: Good 191 of 363 days2006: Moderate 157 of 363 days2006: Unhealthy for Sensitive Groups 15 of 363 days2007: Good 186 of 362 days2007: Moderate 148 of 362 days2007: Unhealthy for Sensitive Groups 27 of 362 days2007: Unhealthy 1 of 362 days2008: Good 236 of 365 days2008: Moderate 124 of 365 days2008: Unhealthy for Sensitive Groups 5 of 365 days2009: Good 294 of 363 days2009: Moderate 69 of 363 days2010: Good 227 of 358 days2010: Moderate 127 of 358 days2010: Unhealthy for Sensitive Groups 4 of 358 days20102011: Good 231 of 336 days2011: Moderate 104 of 336 days2011: Unhealthy for Sensitive Groups 1 of 336 days2012: Good 262 of 361 days2012: Moderate 94 of 361 days2012: Unhealthy for Sensitive Groups 5 of 361 days2013: Good 288 of 360 days2013: Moderate 72 of 360 days2014: Good 281 of 360 days2014: Moderate 79 of 360 days2015: Good 294 of 363 days2015: Moderate 68 of 363 days2015: Unhealthy for Sensitive Groups 1 of 363 days20152016: Good 282 of 348 days2016: Moderate 65 of 348 days2016: Unhealthy for Sensitive Groups 1 of 348 days2017: Good 305 of 359 days2017: Moderate 54 of 359 days2018: Good 302 of 350 days2018: Moderate 48 of 350 days2019: Good 303 of 361 days2019: Moderate 58 of 361 days2020: Good 332 of 364 days2020: Moderate 32 of 364 days20202021: Good 315 of 361 days2021: Moderate 46 of 361 days2022: Good 323 of 364 days2022: Moderate 41 of 364 days2023: Good 212 of 365 days2023: Moderate 151 of 365 days2023: Unhealthy for Sensitive Groups 2 of 365 days2024: Good 277 of 366 days2024: Moderate 89 of 366 days2025: Good 282 of 365 days2025: Moderate 83 of 365 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 year0501001501990: 90th percentile AQI 1191991: 90th percentile AQI 801992: 90th percentile AQI 771993: 90th percentile AQI 901994: 90th percentile AQI 771995: 90th percentile AQI 1051996: 90th percentile AQI 1001997: 90th percentile AQI 801998: 90th percentile AQI 1291999: 90th percentile AQI 1332000: 90th percentile AQI 1152001: 90th percentile AQI 972002: 90th percentile AQI 932003: 90th percentile AQI 802004: 90th percentile AQI 742005: 90th percentile AQI 752006: 90th percentile AQI 842007: 90th percentile AQI 932008: 90th percentile AQI 742009: 90th percentile AQI 582010: 90th percentile AQI 742011: 90th percentile AQI 652012: 90th percentile AQI 642013: 90th percentile AQI 552014: 90th percentile AQI 572015: 90th percentile AQI 552016: 90th percentile AQI 562017: 90th percentile AQI 542018: 90th percentile AQI 542019: 90th percentile AQI 542020: 90th percentile AQI 492021: 90th percentile AQI 532022: 90th percentile AQI 522023: 90th percentile AQI 662024: 90th percentile AQI 572025: 90th percentile AQI 561990: Median AQI 471991: Median AQI 411992: Median AQI 381993: Median AQI 441994: Median AQI 381995: Median AQI 481996: Median AQI 411997: Median AQI 371998: Median AQI 461999: Median AQI 612000: Median AQI 542001: Median AQI 472002: Median AQI 452003: Median AQI 472004: Median AQI 442005: Median AQI 442006: Median AQI 492007: Median AQI 492008: Median AQI 442009: Median AQI 382010: Median AQI 442011: Median AQI 422012: Median AQI 422013: Median AQI 402014: Median AQI 402015: Median AQI 382016: Median AQI 412017: Median AQI 402018: Median AQI 362019: Median AQI 392020: Median AQI 372021: Median AQI 372022: Median AQI 382023: Median AQI 482024: Median AQI 432025: Median AQI 4119901995200020052010201520202025
  • 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
Ozone23364%
Fine particles (PM2.5)13236%

Year-by-year data

Annual AQI summary by year
YearDays with AQIGoodModerateUnhealthy for Sensitive GroupsUnhealthyVery UnhealthyHazardousMedian AQI90th pct.Max AQIMain pollutant
2025365282830000415693Ozone
2024366277890000435787Ozone
202336521215120004866133PM2.5
2022364323410000385297Ozone
2021361315460000375384Ozone
2020364332320000374991Ozone
2019361303580000395490Ozone
2018350302480000365484Ozone
2017359305540000405480Ozone
20163482826510004156119Ozone
20153632946810003855101Ozone
2014360281790000405790Ozone
2013360288720000405593Ozone
20123612629450004264115Ozone
201133623110410004265101Ozone
201035822712740004474101Ozone
20093632946900003858100Ozone
200836523612450004474122Ozone
2007362186148271004993169Ozone
2006363191157150004984140Ozone
200535822013080004475140Ozone
200436122812670004474115Ozone
2003361208140112004780164Ozone
2002360212121243004593164Ozone
2001365198136283004797164Ozone
20003541611315840054115159Ozone
199933212712660190061133195Ozone
19983632158445172046129205Ozone
199730723158171003780179Ozone
1996225147561660041100182Ozone
1995285152982870048105190Ozone
199434726670110003877143Ozone
199335724486225004490177Ozone
199234926371132003877169Ozone
199134224982101004180151Ozone
19903602048955111047119201Ozone

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 Alabama with a similar median AQI in 2025

All monitored counties in Alabama

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