EnviroNearby

Caldwell County, North Carolina air quality history

Daily Air Quality Index summaries from EPA monitors in Caldwell, North Carolina, 1981–2025.

97%
Good days in 2025
36
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 Caldwell, North Carolina on 245 days. 238 of those days (97%) were in the Good range, and the median daily AQI was 36. That median is lower than 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 56% in 1982–1984 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 (1981) 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%1981: Good 79 of 119 days1981: Moderate 35 of 119 days1981: Unhealthy for Sensitive Groups 4 of 119 days1981: Unhealthy 1 of 119 days19811982: Good 96 of 175 days1982: Moderate 62 of 175 days1982: Unhealthy for Sensitive Groups 15 of 175 days1982: Unhealthy 2 of 175 days1983: Good 116 of 216 days1983: Moderate 57 of 216 days1983: Unhealthy for Sensitive Groups 36 of 216 days1983: Unhealthy 7 of 216 days1984: Good 137 of 225 days1984: Moderate 66 of 225 days1984: Unhealthy for Sensitive Groups 22 of 225 days1986: Good 132 of 210 days1986: Moderate 65 of 210 days1986: Unhealthy for Sensitive Groups 13 of 210 days1989: Good 121 of 211 days1989: Moderate 73 of 211 days1989: Unhealthy for Sensitive Groups 17 of 211 days19891991: Good 131 of 211 days1991: Moderate 72 of 211 days1991: Unhealthy for Sensitive Groups 7 of 211 days1991: Unhealthy 1 of 211 days1993: Good 113 of 206 days1993: Moderate 79 of 206 days1993: Unhealthy for Sensitive Groups 14 of 206 days1995: Good 91 of 213 days1995: Moderate 95 of 213 days1995: Unhealthy for Sensitive Groups 26 of 213 days1995: Unhealthy 1 of 213 days1997: Good 113 of 214 days1997: Moderate 89 of 214 days1997: Unhealthy for Sensitive Groups 12 of 214 days1998: Good 85 of 213 days1998: Moderate 74 of 213 days1998: Unhealthy for Sensitive Groups 45 of 213 days1998: Unhealthy 8 of 213 days1998: Very Unhealthy 1 of 213 days19981999: Good 70 of 214 days1999: Moderate 85 of 214 days1999: Unhealthy for Sensitive Groups 44 of 214 days1999: Unhealthy 15 of 214 days2000: Good 97 of 203 days2000: Moderate 72 of 203 days2000: Unhealthy for Sensitive Groups 31 of 203 days2000: Unhealthy 3 of 203 days2001: Good 124 of 212 days2001: Moderate 66 of 212 days2001: Unhealthy for Sensitive Groups 20 of 212 days2001: Unhealthy 2 of 212 days2002: Good 114 of 214 days2002: Moderate 66 of 214 days2002: Unhealthy for Sensitive Groups 25 of 214 days2002: Unhealthy 9 of 214 days2003: Good 136 of 213 days2003: Moderate 64 of 213 days2003: Unhealthy for Sensitive Groups 10 of 213 days2003: Unhealthy 3 of 213 days20032004: Good 166 of 208 days2004: Moderate 39 of 208 days2004: Unhealthy for Sensitive Groups 3 of 208 days2005: Good 144 of 211 days2005: Moderate 54 of 211 days2005: Unhealthy for Sensitive Groups 13 of 211 days2006: Good 141 of 213 days2006: Moderate 66 of 213 days2006: Unhealthy for Sensitive Groups 6 of 213 days2007: Good 110 of 204 days2007: Moderate 81 of 204 days2007: Unhealthy for Sensitive Groups 13 of 204 days2008: Good 141 of 214 days2008: Moderate 66 of 214 days2008: Unhealthy for Sensitive Groups 7 of 214 days20082009: Good 190 of 213 days2009: Moderate 23 of 213 days2010: Good 149 of 212 days2010: Moderate 59 of 212 days2010: Unhealthy for Sensitive Groups 4 of 212 days2011: Good 161 of 214 days2011: Moderate 53 of 214 days2012: Good 182 of 214 days2012: Moderate 31 of 214 days2012: Unhealthy for Sensitive Groups 1 of 214 days2013: Good 203 of 214 days2013: Moderate 11 of 214 days20132014: Good 194 of 211 days2014: Moderate 17 of 211 days2015: Good 173 of 207 days2015: Moderate 34 of 207 days2016: Good 180 of 214 days2016: Moderate 34 of 214 days2017: Good 209 of 239 days2017: Moderate 30 of 239 days2018: Good 209 of 244 days2018: Moderate 35 of 244 days20182019: Good 214 of 243 days2019: Moderate 29 of 243 days2020: Good 243 of 243 days2021: Good 219 of 243 days2021: Moderate 24 of 243 days2022: Good 224 of 245 days2022: Moderate 21 of 245 days2023: Good 220 of 245 days2023: Moderate 25 of 245 days20232024: Good 221 of 237 days2024: Moderate 16 of 237 days2025: Good 238 of 245 days2025: Moderate 7 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 year0501001501981: 90th percentile AQI 871982: 90th percentile AQI 1001983: 90th percentile AQI 1191984: 90th percentile AQI 1001986: 90th percentile AQI 971989: 90th percentile AQI 931991: 90th percentile AQI 841993: 90th percentile AQI 931995: 90th percentile AQI 1051997: 90th percentile AQI 931998: 90th percentile AQI 1331999: 90th percentile AQI 1432000: 90th percentile AQI 1152001: 90th percentile AQI 1052002: 90th percentile AQI 1262003: 90th percentile AQI 872004: 90th percentile AQI 672005: 90th percentile AQI 802006: 90th percentile AQI 772007: 90th percentile AQI 972008: 90th percentile AQI 802009: 90th percentile AQI 512010: 90th percentile AQI 742011: 90th percentile AQI 612012: 90th percentile AQI 582013: 90th percentile AQI 472014: 90th percentile AQI 492015: 90th percentile AQI 612016: 90th percentile AQI 542017: 90th percentile AQI 582018: 90th percentile AQI 582019: 90th percentile AQI 542020: 90th percentile AQI 442021: 90th percentile AQI 502022: 90th percentile AQI 502023: 90th percentile AQI 512024: 90th percentile AQI 492025: 90th percentile AQI 461981: Median AQI 441982: Median AQI 491983: Median AQI 491984: Median AQI 461986: Median AQI 461989: Median AQI 481991: Median AQI 471993: Median AQI 481995: Median AQI 611997: Median AQI 491998: Median AQI 611999: Median AQI 712000: Median AQI 512001: Median AQI 492002: Median AQI 492003: Median AQI 462004: Median AQI 412005: Median AQI 462006: Median AQI 472007: Median AQI 492008: Median AQI 482009: Median AQI 372010: Median AQI 442011: Median AQI 452012: Median AQI 422013: Median AQI 372014: Median AQI 382015: Median AQI 422016: Median AQI 432017: Median AQI 422018: Median AQI 392019: Median AQI 422020: Median AQI 342021: Median AQI 402022: Median AQI 402023: Median AQI 402024: Median AQI 402025: Median AQI 36198119891998200320082013201820232025
  • 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
202524523870000364677Ozone
2024237221160000404987Ozone
2023245220250000405197Ozone
2022245224210000405074Ozone
2021243219240000405077Ozone
202024324300000344450Ozone
2019243214290000425474Ozone
2018244209350000395893Ozone
2017239209300000425890Ozone
2016214180340000435490Ozone
2015207173340000426197Ozone
20142111941700003849100Ozone
2013214203110000374793Ozone
20122141823110004258129Ozone
20112141615300004561100Ozone
20102121495940004474122Ozone
2009213190230000375190Ozone
20082141416670004880126Ozone
200720411081130004997136Ozone
20062131416660004777136Ozone
200521114454130004680133Ozone
20042081663930004167112Ozone
200321313664103004687154Ozone
2002214114662590049126185Ozone
2001212124662020049105154Ozone
200020397723130051115164Ozone
1999214708544150071143195Ozone
199821385744581061133204Ozone
199721411389120004993150Ozone
199521391952610061105166Ozone
199320611379140004893140Ozone
19912111317271004784164Ozone
198921112173170004893136Ozone
198621013265130004697140Ozone
1984225137662200046100147Ozone
1983216116573670049119177Ozone
198217596621520049100156Ozone
1981119793541004487166Ozone

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 1981–2025 (EPA download page). EPA file dates: 2026-06-26. Imported into EnviroNearby November 5, 2026. How we use this data · Report a problem