EnviroNearby

Caswell County, North Carolina air quality history

Daily Air Quality Index summaries from EPA monitors in Caswell, North Carolina, 1993–2025.

95%
Good days in 2025
37
Median daily AQI, 2025
0
Days above 100 in 2025
245
Days with an AQI in 2025 (of 365)

In 2025, EPA reported a daily Air Quality Index (AQI) for Caswell, North Carolina on 245 days. 233 of those days (95%) were in the Good range, and the median daily AQI was 37. That median is about the same as the typical monitored county in North Carolina (median 39 across 33 counties), and lower than the typical monitored U.S. county (40). The main pollutant was ozone on 245 days. Across the years with fuller monitoring, the share of Good days rose: an average of 52% in 1994–1996 versus 93% in 2023–2025.

EPA did not report an AQI for every day of 2025 here (245 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.

Years with fewer than 120 monitored days (1993) 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%1993: Good 21 of 64 days1993: Moderate 22 of 64 days1993: Unhealthy for Sensitive Groups 13 of 64 days1993: Unhealthy 8 of 64 days19931994: Good 101 of 183 days1994: Moderate 59 of 183 days1994: Unhealthy for Sensitive Groups 20 of 183 days1994: Unhealthy 2 of 183 days1994: Very Unhealthy 1 of 183 days1995: Good 136 of 213 days1995: Moderate 60 of 213 days1995: Unhealthy for Sensitive Groups 13 of 213 days1995: Unhealthy 4 of 213 days1996: Good 66 of 174 days1996: Moderate 67 of 174 days1996: Unhealthy for Sensitive Groups 35 of 174 days1996: Unhealthy 6 of 174 days1997: Good 77 of 213 days1997: Moderate 74 of 213 days1997: Unhealthy for Sensitive Groups 47 of 213 days1997: Unhealthy 15 of 213 days1998: Good 90 of 214 days1998: Moderate 60 of 214 days1998: Unhealthy for Sensitive Groups 50 of 214 days1998: Unhealthy 14 of 214 days19981999: Good 108 of 239 days1999: Moderate 107 of 239 days1999: Unhealthy for Sensitive Groups 18 of 239 days1999: Unhealthy 6 of 239 days2000: Good 99 of 262 days2000: Moderate 121 of 262 days2000: Unhealthy for Sensitive Groups 33 of 262 days2000: Unhealthy 9 of 262 days2001: Good 103 of 260 days2001: Moderate 121 of 260 days2001: Unhealthy for Sensitive Groups 31 of 260 days2001: Unhealthy 5 of 260 days2002: Good 105 of 260 days2002: Moderate 118 of 260 days2002: Unhealthy for Sensitive Groups 23 of 260 days2002: Unhealthy 13 of 260 days2002: Very Unhealthy 1 of 260 days2003: Good 130 of 265 days2003: Moderate 115 of 265 days2003: Unhealthy for Sensitive Groups 17 of 265 days2003: Unhealthy 3 of 265 days20032004: Good 150 of 262 days2004: Moderate 106 of 262 days2004: Unhealthy for Sensitive Groups 6 of 262 days2005: Good 123 of 260 days2005: Moderate 125 of 260 days2005: Unhealthy for Sensitive Groups 12 of 260 days2006: Good 86 of 351 days2006: Moderate 250 of 351 days2006: Unhealthy for Sensitive Groups 15 of 351 days2007: Good 109 of 363 days2007: Moderate 219 of 363 days2007: Unhealthy for Sensitive Groups 34 of 363 days2007: Unhealthy 1 of 363 days2008: Good 125 of 366 days2008: Moderate 229 of 366 days2008: Unhealthy for Sensitive Groups 10 of 366 days2008: Unhealthy 2 of 366 days20082009: Good 157 of 362 days2009: Moderate 204 of 362 days2009: Unhealthy for Sensitive Groups 1 of 362 days2010: Good 176 of 365 days2010: Moderate 183 of 365 days2010: Unhealthy for Sensitive Groups 6 of 365 days2011: Good 182 of 363 days2011: Moderate 178 of 363 days2011: Unhealthy for Sensitive Groups 3 of 363 days2012: Good 162 of 353 days2012: Moderate 187 of 353 days2012: Unhealthy for Sensitive Groups 4 of 353 days2013: Good 171 of 364 days2013: Moderate 192 of 364 days2013: Unhealthy for Sensitive Groups 1 of 364 days20132014: Good 155 of 357 days2014: Moderate 202 of 357 days2015: Good 212 of 358 days2015: Moderate 146 of 358 days2016: Good 303 of 329 days2016: Moderate 26 of 329 days2017: Good 275 of 291 days2017: Moderate 16 of 291 days2018: Good 198 of 232 days2018: Moderate 34 of 232 days20182019: Good 236 of 245 days2019: Moderate 9 of 245 days2020: Good 349 of 354 days2020: Moderate 5 of 354 days2021: Good 240 of 250 days2021: Moderate 10 of 250 days2022: Good 253 of 264 days2022: Moderate 11 of 264 days2023: Good 325 of 350 days2023: Moderate 25 of 350 days20232024: Good 225 of 244 days2024: Moderate 19 of 244 days2025: Good 233 of 245 days2025: Moderate 12 of 245 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 year0501001502001993: 90th percentile AQI 1511994: 90th percentile AQI 1051995: 90th percentile AQI 971996: 90th percentile AQI 1261997: 90th percentile AQI 1431998: 90th percentile AQI 1401999: 90th percentile AQI 1012000: 90th percentile AQI 1152001: 90th percentile AQI 1122002: 90th percentile AQI 1222003: 90th percentile AQI 932004: 90th percentile AQI 772005: 90th percentile AQI 902006: 90th percentile AQI 872007: 90th percentile AQI 1002008: 90th percentile AQI 802009: 90th percentile AQI 662010: 90th percentile AQI 732011: 90th percentile AQI 712012: 90th percentile AQI 672013: 90th percentile AQI 642014: 90th percentile AQI 642015: 90th percentile AQI 602016: 90th percentile AQI 492017: 90th percentile AQI 482018: 90th percentile AQI 582019: 90th percentile AQI 472020: 90th percentile AQI 442021: 90th percentile AQI 472022: 90th percentile AQI 482023: 90th percentile AQI 492024: 90th percentile AQI 492025: 90th percentile AQI 471993: Median AQI 801994: Median AQI 481995: Median AQI 441996: Median AQI 641997: Median AQI 671998: Median AQI 641999: Median AQI 542000: Median AQI 572001: Median AQI 572002: Median AQI 562003: Median AQI 512004: Median AQI 472005: Median AQI 512006: Median AQI 582007: Median AQI 572008: Median AQI 542009: Median AQI 522010: Median AQI 512011: Median AQI 502012: Median AQI 522013: Median AQI 512014: Median AQI 522015: Median AQI 472016: Median AQI 332017: Median AQI 372018: Median AQI 402019: Median AQI 392020: Median AQI 312021: Median AQI 382022: Median AQI 392023: Median AQI 362024: Median AQI 382025: Median AQI 3719931998200320082013201820232025
  • 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
Ozone245100%

Year-by-year data

Annual AQI summary by year
YearDays with AQIGoodModerateUnhealthy for Sensitive GroupsUnhealthyVery UnhealthyHazardousMedian AQI90th pct.Max AQIMain pollutant
2025245233120000374777Ozone
2024244225190000384984Ozone
2023350325250000364997Ozone
2022264253110000394864Ozone
2021250240100000384780Ozone
202035434950000314461Ozone
201924523690000394764Ozone
2018232198340000405897Ozone
2017291275160000374871Ozone
2016329303260000334997Ozone
20153582121460000476087PM2.5
20143571552020000526497PM2.5
201336417119210005164112PM2.5
201235316218740005267136PM2.5
201136318217830005071129PM2.5
201036517618360005173126PM2.5
200936215720410005266101PM2.5
2008366125229102005480159PM2.5
20073631092193410057100164PM2.5
200635186250150005887122PM2.5
2005260123125120005190133Ozone
200426215010660004777129Ozone
2003265130115173005193197Ozone
200226010511823131056122208Ozone
20012601031213150057112174Ozone
2000262991213390057115192Ozone
19992391081071860054101177Ozone
1998214906050140064140197Ozone
1997213777447150067143182Ozone
199617466673560064126187Ozone
199521313660134004497187Ozone
1994183101592021048105202Ozone
19936421221380080151179Ozone

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 1993–2025 (EPA download page). EPA file dates: 2026-06-26. Imported into EnviroNearby November 5, 2026. How we use this data · Report a problem