EnviroNearby

Durham County, North Carolina air quality history

Daily Air Quality Index summaries from EPA monitors in Durham, North Carolina, 1980–2025.

72%
Good days in 2025
42
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 Durham, North Carolina on 365 days. 262 of those days (72%) were in the Good range, and the median daily AQI was 42. That median is higher than the typical monitored county in North Carolina (median 39 across 33 counties), and about the same as the typical monitored U.S. county (40). The main pollutant was fine particles (PM2.5) on 227 days. Across the years with fuller monitoring, the share of Good days rose: an average of 55% in 1980–1982 versus 63% 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%1980: Good 185 of 355 days1980: Moderate 148 of 355 days1980: Unhealthy for Sensitive Groups 15 of 355 days1980: Unhealthy 5 of 355 days1980: Very Unhealthy 2 of 355 days19801981: Good 195 of 349 days1981: Moderate 139 of 349 days1981: Unhealthy for Sensitive Groups 12 of 349 days1981: Unhealthy 3 of 349 days1982: Good 204 of 349 days1982: Moderate 122 of 349 days1982: Unhealthy for Sensitive Groups 22 of 349 days1982: Unhealthy 1 of 349 days1983: Good 231 of 359 days1983: Moderate 112 of 359 days1983: Unhealthy for Sensitive Groups 12 of 359 days1983: Unhealthy 4 of 359 days1984: Good 168 of 318 days1984: Moderate 125 of 318 days1984: Unhealthy for Sensitive Groups 16 of 318 days1984: Unhealthy 9 of 318 days1985: Good 250 of 333 days1985: Moderate 76 of 333 days1985: Unhealthy for Sensitive Groups 2 of 333 days1985: Unhealthy 5 of 333 days19851986: Good 234 of 351 days1986: Moderate 110 of 351 days1986: Unhealthy for Sensitive Groups 5 of 351 days1986: Unhealthy 2 of 351 days1987: Good 236 of 365 days1987: Moderate 126 of 365 days1987: Unhealthy for Sensitive Groups 3 of 365 days1988: Good 251 of 366 days1988: Moderate 113 of 366 days1988: Unhealthy for Sensitive Groups 2 of 366 days1989: Good 295 of 365 days1989: Moderate 68 of 365 days1989: Unhealthy for Sensitive Groups 2 of 365 days1990: Good 312 of 365 days1990: Moderate 50 of 365 days1990: Unhealthy for Sensitive Groups 3 of 365 days19901991: Good 326 of 365 days1991: Moderate 39 of 365 days1992: Good 349 of 366 days1992: Moderate 17 of 366 days1993: Good 261 of 365 days1993: Moderate 70 of 365 days1993: Unhealthy for Sensitive Groups 30 of 365 days1993: Unhealthy 4 of 365 days1994: Good 256 of 365 days1994: Moderate 84 of 365 days1994: Unhealthy for Sensitive Groups 22 of 365 days1994: Unhealthy 3 of 365 days1995: Good 250 of 365 days1995: Moderate 81 of 365 days1995: Unhealthy for Sensitive Groups 32 of 365 days1995: Unhealthy 2 of 365 days19951996: Good 265 of 363 days1996: Moderate 73 of 363 days1996: Unhealthy for Sensitive Groups 22 of 363 days1996: Unhealthy 3 of 363 days1997: Good 266 of 365 days1997: Moderate 78 of 365 days1997: Unhealthy for Sensitive Groups 18 of 365 days1997: Unhealthy 3 of 365 days1998: Good 253 of 365 days1998: Moderate 60 of 365 days1998: Unhealthy for Sensitive Groups 37 of 365 days1998: Unhealthy 15 of 365 days1999: Good 94 of 364 days1999: Moderate 237 of 364 days1999: Unhealthy for Sensitive Groups 25 of 364 days1999: Unhealthy 8 of 364 days2000: Good 76 of 364 days2000: Moderate 251 of 364 days2000: Unhealthy for Sensitive Groups 31 of 364 days2000: Unhealthy 6 of 364 days20002001: Good 82 of 356 days2001: Moderate 246 of 356 days2001: Unhealthy for Sensitive Groups 25 of 356 days2001: Unhealthy 3 of 356 days2002: Good 88 of 349 days2002: Moderate 217 of 349 days2002: Unhealthy for Sensitive Groups 28 of 349 days2002: Unhealthy 16 of 349 days2003: Good 112 of 345 days2003: Moderate 217 of 345 days2003: Unhealthy for Sensitive Groups 15 of 345 days2003: Unhealthy 1 of 345 days2004: Good 105 of 360 days2004: Moderate 248 of 360 days2004: Unhealthy for Sensitive Groups 7 of 360 days2005: Good 96 of 342 days2005: Moderate 228 of 342 days2005: Unhealthy for Sensitive Groups 18 of 342 days20052006: Good 108 of 358 days2006: Moderate 237 of 358 days2006: Unhealthy for Sensitive Groups 12 of 358 days2006: Unhealthy 1 of 358 days2007: Good 116 of 296 days2007: Moderate 158 of 296 days2007: Unhealthy for Sensitive Groups 19 of 296 days2007: Unhealthy 3 of 296 days2008: Good 111 of 356 days2008: Moderate 238 of 356 days2008: Unhealthy for Sensitive Groups 7 of 356 days2009: Good 158 of 348 days2009: Moderate 190 of 348 days2010: Good 151 of 364 days2010: Moderate 205 of 364 days2010: Unhealthy for Sensitive Groups 8 of 364 days20102011: Good 178 of 365 days2011: Moderate 184 of 365 days2011: Unhealthy for Sensitive Groups 3 of 365 days2012: Good 214 of 365 days2012: Moderate 144 of 365 days2012: Unhealthy for Sensitive Groups 6 of 365 days2012: Unhealthy 1 of 365 days2013: Good 244 of 365 days2013: Moderate 121 of 365 days2014: Good 217 of 365 days2014: Moderate 148 of 365 days2015: Good 202 of 359 days2015: Moderate 157 of 359 days20152016: Good 194 of 366 days2016: Moderate 171 of 366 days2016: Unhealthy for Sensitive Groups 1 of 366 days2017: Good 191 of 365 days2017: Moderate 174 of 365 days2018: Good 191 of 358 days2018: Moderate 167 of 358 days2019: Good 207 of 364 days2019: Moderate 157 of 364 days2020: Good 276 of 364 days2020: Moderate 88 of 364 days20202021: Good 238 of 365 days2021: Moderate 127 of 365 days2022: Good 273 of 365 days2022: Moderate 92 of 365 days2023: Good 252 of 361 days2023: Moderate 106 of 361 days2023: Unhealthy for Sensitive Groups 3 of 361 days2024: Good 170 of 366 days2024: Moderate 196 of 366 days2025: Good 262 of 365 days2025: Moderate 103 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 year0501001501980: 90th percentile AQI 871981: 90th percentile AQI 841982: 90th percentile AQI 891983: 90th percentile AQI 841984: 90th percentile AQI 951985: 90th percentile AQI 681986: 90th percentile AQI 791987: 90th percentile AQI 781988: 90th percentile AQI 671989: 90th percentile AQI 591990: 90th percentile AQI 541991: 90th percentile AQI 521992: 90th percentile AQI 421993: 90th percentile AQI 971994: 90th percentile AQI 931995: 90th percentile AQI 1001996: 90th percentile AQI 871997: 90th percentile AQI 801998: 90th percentile AQI 1151999: 90th percentile AQI 982000: 90th percentile AQI 1032001: 90th percentile AQI 972002: 90th percentile AQI 1192003: 90th percentile AQI 842004: 90th percentile AQI 802005: 90th percentile AQI 872006: 90th percentile AQI 832007: 90th percentile AQI 972008: 90th percentile AQI 772009: 90th percentile AQI 642010: 90th percentile AQI 682011: 90th percentile AQI 742012: 90th percentile AQI 642013: 90th percentile AQI 592014: 90th percentile AQI 592015: 90th percentile AQI 642016: 90th percentile AQI 622017: 90th percentile AQI 622018: 90th percentile AQI 622019: 90th percentile AQI 602020: 90th percentile AQI 552021: 90th percentile AQI 592022: 90th percentile AQI 552023: 90th percentile AQI 632024: 90th percentile AQI 612025: 90th percentile AQI 571980: Median AQI 491981: Median AQI 471982: Median AQI 421983: Median AQI 391984: Median AQI 501985: Median AQI 361986: Median AQI 421987: Median AQI 401988: Median AQI 401989: Median AQI 331990: Median AQI 331991: Median AQI 301992: Median AQI 231993: Median AQI 361994: Median AQI 401995: Median AQI 361996: Median AQI 401997: Median AQI 411998: Median AQI 381999: Median AQI 592000: Median AQI 632001: Median AQI 612002: Median AQI 582003: Median AQI 572004: Median AQI 582005: Median AQI 582006: Median AQI 582007: Median AQI 552008: Median AQI 562009: Median AQI 522010: Median AQI 532011: Median AQI 512012: Median AQI 472013: Median AQI 432014: Median AQI 462015: Median AQI 482016: Median AQI 492017: Median AQI 492018: Median AQI 482019: Median AQI 472020: Median AQI 402021: Median AQI 442022: Median AQI 422023: Median AQI 442024: Median AQI 512025: Median AQI 421980198519901995200020052010201520202025
  • 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)22762%
Ozone13637%
Coarse particles (PM10)21%

Year-by-year data

Annual AQI summary by year
YearDays with AQIGoodModerateUnhealthy for Sensitive GroupsUnhealthyVery UnhealthyHazardousMedian AQI90th pct.Max AQIMain pollutant
20253652621030000425777PM2.5
20243661701960000516197PM2.5
202336125210630004463121PM2.5
2022365273920000425593PM2.5
20213652381270000445990PM2.5
2020364276880000405597PM2.5
20193642071570000476087PM2.5
201835819116700004862100PM2.5
201736519117400004962100PM2.5
201636619417110004962119PM2.5
20153592021570000486487PM2.5
20143652171480000465990PM2.5
20133652441210000435987PM2.5
201236521414461004764151PM2.5
201136517818430005174122PM2.5
201036415120580005368129PM2.5
20093481581900000526497PM2.5
200835611123870005677143PM2.5
2007296116158193005597166Ozone
2006358108237121005883159PM2.5
200534296228180005887140PM2.5
200436010524870005880136PM2.5
2003345112217151005784182PM2.5
20023498821728160058119195PM2.5
200135682246253006197182PM2.5
2000364762513160063103182PM2.5
199936494237258005998192PM2.5
19983652536037150038115197Ozone
199736526678183004180161Ozone
199636326573223004087169Ozone
1995365250813220036100156Ozone
199436525684223004093172Ozone
199336526170304003697166CO
1992366349170000234291CO
1991365326390000305295CO
19903653125030003354120CO
19893652956820003359145CO
198836625111320004067130CO
198736523612630004078118CO
198635123411052004279181CO
19853332507625003668166CO
1984318168125169005095190CO
1983359231112124003984166CO
1982349204122221004289163CO
1981349195139123004784158CO
1980355185148155204987210CO

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 North Carolina with a similar median AQI in 2025

All monitored counties in North Carolina

Source: U.S. EPA AirData, “Annual AQI by County” files for 1980–2025 (EPA download page). EPA file dates: 2026-06-26. Imported into EnviroNearby November 5, 2026. How we use this data · Report a problem