EnviroNearby

Swain County, North Carolina air quality history

Daily Air Quality Index summaries from EPA monitors in Swain, North Carolina, 1995–2025.

81%
Good days in 2025
37
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 Swain, North Carolina on 365 days. 296 of those days (81%) 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 fine particles (PM2.5) on 241 days. Across the years with fuller monitoring, the share of Good days fell: an average of 82% in 1995–1997 versus 79% 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%1995: Good 173 of 213 days1995: Moderate 40 of 213 days19951996: Good 180 of 203 days1996: Moderate 23 of 203 days1997: Good 181 of 234 days1997: Moderate 50 of 234 days1997: Unhealthy for Sensitive Groups 3 of 234 days1998: Good 144 of 238 days1998: Moderate 70 of 238 days1998: Unhealthy for Sensitive Groups 23 of 238 days1998: Unhealthy 1 of 238 days1999: Good 99 of 257 days1999: Moderate 145 of 257 days1999: Unhealthy for Sensitive Groups 13 of 257 days2000: Good 130 of 261 days2000: Moderate 126 of 261 days2000: Unhealthy for Sensitive Groups 5 of 261 days20002001: Good 146 of 261 days2001: Moderate 106 of 261 days2001: Unhealthy for Sensitive Groups 7 of 261 days2001: Unhealthy 2 of 261 days2002: Good 141 of 260 days2002: Moderate 109 of 260 days2002: Unhealthy for Sensitive Groups 10 of 260 days2003: Good 154 of 258 days2003: Moderate 99 of 258 days2003: Unhealthy for Sensitive Groups 5 of 258 days2004: Good 169 of 260 days2004: Moderate 91 of 260 days2005: Good 156 of 260 days2005: Moderate 101 of 260 days2005: Unhealthy for Sensitive Groups 3 of 260 days20052006: Good 101 of 360 days2006: Moderate 259 of 360 days2007: Good 104 of 363 days2007: Moderate 255 of 363 days2007: Unhealthy for Sensitive Groups 4 of 363 days2008: Good 121 of 365 days2008: Moderate 244 of 365 days2009: Good 191 of 365 days2009: Moderate 174 of 365 days2010: Good 151 of 359 days2010: Moderate 208 of 359 days20102011: Good 136 of 362 days2011: Moderate 226 of 362 days2012: Good 210 of 360 days2012: Moderate 150 of 360 days2013: Good 236 of 355 days2013: Moderate 119 of 355 days2014: Good 224 of 359 days2014: Moderate 135 of 359 days2015: Good 244 of 360 days2015: Moderate 116 of 360 days20152016: Good 244 of 365 days2016: Moderate 109 of 365 days2016: Unhealthy for Sensitive Groups 8 of 365 days2016: Unhealthy 4 of 365 days2017: Good 234 of 365 days2017: Moderate 131 of 365 days2018: Good 255 of 363 days2018: Moderate 108 of 363 days2019: Good 259 of 362 days2019: Moderate 103 of 362 days2020: Good 301 of 362 days2020: Moderate 60 of 362 days2020: Unhealthy for Sensitive Groups 1 of 362 days20202021: Good 261 of 354 days2021: Moderate 92 of 354 days2021: Unhealthy for Sensitive Groups 1 of 354 days2022: Good 275 of 365 days2022: Moderate 90 of 365 days2023: Good 267 of 365 days2023: Moderate 96 of 365 days2023: Unhealthy for Sensitive Groups 2 of 365 days2024: Good 305 of 366 days2024: Moderate 61 of 366 days2025: Good 296 of 365 days2025: Moderate 69 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 year0501001501995: 90th percentile AQI 581996: 90th percentile AQI 511997: 90th percentile AQI 671998: 90th percentile AQI 1011999: 90th percentile AQI 932000: 90th percentile AQI 742001: 90th percentile AQI 802002: 90th percentile AQI 842003: 90th percentile AQI 742004: 90th percentile AQI 672005: 90th percentile AQI 732006: 90th percentile AQI 742007: 90th percentile AQI 772008: 90th percentile AQI 712009: 90th percentile AQI 612010: 90th percentile AQI 652011: 90th percentile AQI 672012: 90th percentile AQI 602013: 90th percentile AQI 602014: 90th percentile AQI 622015: 90th percentile AQI 602016: 90th percentile AQI 642017: 90th percentile AQI 582018: 90th percentile AQI 582019: 90th percentile AQI 562020: 90th percentile AQI 532021: 90th percentile AQI 582022: 90th percentile AQI 572023: 90th percentile AQI 592024: 90th percentile AQI 532025: 90th percentile AQI 541995: Median AQI 421996: Median AQI 401997: Median AQI 421998: Median AQI 471999: Median AQI 582000: Median AQI 512001: Median AQI 482002: Median AQI 482003: Median AQI 462004: Median AQI 442005: Median AQI 462006: Median AQI 562007: Median AQI 582008: Median AQI 552009: Median AQI 492010: Median AQI 532011: Median AQI 552012: Median AQI 472013: Median AQI 432014: Median AQI 442015: Median AQI 422016: Median AQI 442017: Median AQI 442018: Median AQI 422019: Median AQI 422020: Median AQI 382021: Median AQI 402022: Median AQI 432023: Median AQI 412024: Median AQI 382025: Median AQI 371995200020052010201520202025
  • 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)24166%
Ozone12434%

Year-by-year data

Annual AQI summary by year
YearDays with AQIGoodModerateUnhealthy for Sensitive GroupsUnhealthyVery UnhealthyHazardousMedian AQI90th pct.Max AQIMain pollutant
2025365296690000375487PM2.5
2024366305610000385383PM2.5
20233652679620004159115PM2.5
2022365275900000435789PM2.5
20213542619210004058147Ozone
20203623016010003853119PM2.5
20193622591030000425690PM2.5
20183632551080000425881PM2.5
20173652341310000445871PM2.5
201636524410984004464182PM2.5
20153602441160000426087PM2.5
20143592241350000446284PM2.5
20133552361190000436093PM2.5
20123602101500000476084PM2.5
20113621362260000556782PM2.5
20103591512080000536597PM2.5
20093651911740000496184PM2.5
200836512124400005571100PM2.5
200736310425540005877120PM2.5
20063601012590000567494PM2.5
200526015610130004673119Ozone
20042601699100004467100Ozone
20032581549950004674126Ozone
2002260141109100004884147Ozone
200126114610672004880157Ozone
200026113012650005174119Ozone
199925799145130005893140Ozone
1998238144702310047101151Ozone
19972341815030004267129Ozone
1996203180230000405184Ozone
19952131734000004258100Ozone

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 1995–2025 (EPA download page). EPA file dates: 2026-06-26. Imported into EnviroNearby November 5, 2026. How we use this data · Report a problem