EnviroNearby

Montgomery County, North Carolina air quality history

Daily Air Quality Index summaries from EPA monitors in Montgomery, North Carolina, 1982–2025.

82%
Good days in 2025
39
Median daily AQI, 2025
0
Days above 100 in 2025
363
Days with an AQI in 2025 (of 365)

In 2025, EPA reported a daily Air Quality Index (AQI) for Montgomery, North Carolina on 363 days. 297 of those days (82%) were in the Good range, and the median daily AQI was 39. That median is about the same as 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 ozone on 203 days. Across the years with fuller monitoring, the share of Good days rose: an average of 59% in 1982–1984 versus 69% in 2023–2025.

Years with fewer than 120 monitored days (1990) 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%1982: Good 93 of 129 days1982: Moderate 33 of 129 days1982: Unhealthy for Sensitive Groups 3 of 129 days19821983: Good 98 of 184 days1983: Moderate 52 of 184 days1983: Unhealthy for Sensitive Groups 27 of 184 days1983: Unhealthy 6 of 184 days1983: Very Unhealthy 1 of 184 days1984: Good 112 of 217 days1984: Moderate 68 of 217 days1984: Unhealthy for Sensitive Groups 29 of 217 days1984: Unhealthy 8 of 217 days1990: Good 74 of 82 days1990: Moderate 8 of 82 days1991: Good 253 of 360 days1991: Moderate 93 of 360 days1991: Unhealthy for Sensitive Groups 13 of 360 days1991: Unhealthy 1 of 360 days1992: Good 254 of 362 days1992: Moderate 90 of 362 days1992: Unhealthy for Sensitive Groups 15 of 362 days1992: Unhealthy 3 of 362 days19921993: Good 221 of 359 days1993: Moderate 100 of 359 days1993: Unhealthy for Sensitive Groups 35 of 359 days1993: Unhealthy 3 of 359 days1994: Good 247 of 349 days1994: Moderate 83 of 349 days1994: Unhealthy for Sensitive Groups 18 of 349 days1994: Unhealthy 1 of 349 days1995: Good 158 of 260 days1995: Moderate 81 of 260 days1995: Unhealthy for Sensitive Groups 20 of 260 days1995: Unhealthy 1 of 260 days1996: Good 128 of 207 days1996: Moderate 54 of 207 days1996: Unhealthy for Sensitive Groups 19 of 207 days1996: Unhealthy 6 of 207 days1997: Good 198 of 346 days1997: Moderate 108 of 346 days1997: Unhealthy for Sensitive Groups 36 of 346 days1997: Unhealthy 3 of 346 days1997: Very Unhealthy 1 of 346 days19971998: Good 210 of 355 days1998: Moderate 87 of 355 days1998: Unhealthy for Sensitive Groups 42 of 355 days1998: Unhealthy 16 of 355 days1999: Good 202 of 363 days1999: Moderate 103 of 363 days1999: Unhealthy for Sensitive Groups 42 of 363 days1999: Unhealthy 16 of 363 days2000: Good 184 of 354 days2000: Moderate 147 of 354 days2000: Unhealthy for Sensitive Groups 22 of 354 days2000: Unhealthy 1 of 354 days2001: Good 209 of 362 days2001: Moderate 132 of 362 days2001: Unhealthy for Sensitive Groups 20 of 362 days2001: Unhealthy 1 of 362 days2002: Good 223 of 362 days2002: Moderate 112 of 362 days2002: Unhealthy for Sensitive Groups 20 of 362 days2002: Unhealthy 7 of 362 days20022003: Good 235 of 349 days2003: Moderate 104 of 349 days2003: Unhealthy for Sensitive Groups 9 of 349 days2003: Unhealthy 1 of 349 days2004: Good 232 of 350 days2004: Moderate 114 of 350 days2004: Unhealthy for Sensitive Groups 4 of 350 days2005: Good 238 of 364 days2005: Moderate 115 of 364 days2005: Unhealthy for Sensitive Groups 11 of 364 days2006: Good 240 of 364 days2006: Moderate 121 of 364 days2006: Unhealthy for Sensitive Groups 2 of 364 days2006: Unhealthy 1 of 364 days2007: Good 215 of 364 days2007: Moderate 137 of 364 days2007: Unhealthy for Sensitive Groups 12 of 364 days20072008: Good 231 of 349 days2008: Moderate 110 of 349 days2008: Unhealthy for Sensitive Groups 8 of 349 days2009: Good 267 of 340 days2009: Moderate 72 of 340 days2009: Unhealthy for Sensitive Groups 1 of 340 days2010: Good 221 of 331 days2010: Moderate 106 of 331 days2010: Unhealthy for Sensitive Groups 4 of 331 days2011: Good 230 of 342 days2011: Moderate 111 of 342 days2011: Unhealthy for Sensitive Groups 1 of 342 days2012: Good 294 of 361 days2012: Moderate 65 of 361 days2012: Unhealthy for Sensitive Groups 1 of 361 days2012: Unhealthy 1 of 361 days20122013: Good 274 of 361 days2013: Moderate 87 of 361 days2014: Good 184 of 365 days2014: Moderate 181 of 365 days2015: Good 235 of 362 days2015: Moderate 127 of 362 days2016: Good 288 of 365 days2016: Moderate 77 of 365 days2017: Good 307 of 365 days2017: Moderate 58 of 365 days20172018: Good 282 of 363 days2018: Moderate 81 of 363 days2019: Good 256 of 365 days2019: Moderate 109 of 365 days2020: Good 281 of 366 days2020: Moderate 85 of 366 days2021: Good 257 of 365 days2021: Moderate 108 of 365 days2022: Good 263 of 363 days2022: Moderate 100 of 363 days20222023: Good 200 of 363 days2023: Moderate 160 of 363 days2023: Unhealthy for Sensitive Groups 3 of 363 days2024: Good 257 of 366 days2024: Moderate 109 of 366 days2025: Good 297 of 363 days2025: Moderate 66 of 363 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 year0501001501982: 90th percentile AQI 711983: 90th percentile AQI 1221984: 90th percentile AQI 1221990: 90th percentile AQI 481991: 90th percentile AQI 871992: 90th percentile AQI 871993: 90th percentile AQI 1051994: 90th percentile AQI 871995: 90th percentile AQI 971996: 90th percentile AQI 1081997: 90th percentile AQI 1051998: 90th percentile AQI 1221999: 90th percentile AQI 1152000: 90th percentile AQI 932001: 90th percentile AQI 902002: 90th percentile AQI 892003: 90th percentile AQI 742004: 90th percentile AQI 772005: 90th percentile AQI 732006: 90th percentile AQI 712007: 90th percentile AQI 802008: 90th percentile AQI 712009: 90th percentile AQI 612010: 90th percentile AQI 652011: 90th percentile AQI 662012: 90th percentile AQI 572013: 90th percentile AQI 602014: 90th percentile AQI 642015: 90th percentile AQI 582016: 90th percentile AQI 552017: 90th percentile AQI 532018: 90th percentile AQI 552019: 90th percentile AQI 582020: 90th percentile AQI 552021: 90th percentile AQI 582022: 90th percentile AQI 582023: 90th percentile AQI 632024: 90th percentile AQI 572025: 90th percentile AQI 531982: Median AQI 401983: Median AQI 491984: Median AQI 491990: Median AQI 321991: Median AQI 421992: Median AQI 421993: Median AQI 441994: Median AQI 401995: Median AQI 451996: Median AQI 451997: Median AQI 471998: Median AQI 461999: Median AQI 482000: Median AQI 502001: Median AQI 462002: Median AQI 442003: Median AQI 412004: Median AQI 412005: Median AQI 432006: Median AQI 442007: Median AQI 472008: Median AQI 442009: Median AQI 382010: Median AQI 432011: Median AQI 432012: Median AQI 402013: Median AQI 422014: Median AQI 502015: Median AQI 452016: Median AQI 412017: Median AQI 412018: Median AQI 392019: Median AQI 442020: Median AQI 402021: Median AQI 432022: Median AQI 432023: Median AQI 482024: Median AQI 422025: Median AQI 39198219921997200220072012201720222025
  • 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
Ozone20356%
Fine particles (PM2.5)16044%

Year-by-year data

Annual AQI summary by year
YearDays with AQIGoodModerateUnhealthy for Sensitive GroupsUnhealthyVery UnhealthyHazardousMedian AQI90th pct.Max AQIMain pollutant
2025363297660000395385Ozone
20243662571090000425783PM2.5
202336320016030004863134PM2.5
20223632631000000435880PM2.5
20213652571080000435880PM2.5
2020366281850000405585PM2.5
20193652561090000445871PM2.5
2018363282810000395598PM2.5
2017365307580000415371Ozone
2016365288770000415587Ozone
20153622351270000455880PM2.5
20143651841810000506484PM2.5
2013361274870000426080Ozone
20123612946511004057151Ozone
201134223011110004366112Ozone
201033122110640004365129Ozone
20093402677210003861108Ozone
200834923111080004471147Ozone
2007364215137120004780147Ozone
200636424012121004471161Ozone
2005364238115110004373147Ozone
200435023211440004177136Ozone
200334923510491004174151Ozone
2002362223112207004489187Ozone
2001362209132201004690151Ozone
2000354184147221005093159Ozone
199936320210342160048115187Ozone
19983552108742160046122200Ozone
19973461981083631047105206Ozone
1996207128541960045108185Ozone
199526015881201004597197Ozone
199434924783181004087166Ozone
19933592211003530044105174Ozone
199236225490153004287166Ozone
199136025393131004287190Ozone
1990827480000324893Ozone
1984217112682980049122177Ozone
198318498522761049122205Ozone
1982129933330004071140Ozone

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 1982–2025 (EPA download page). EPA file dates: 2026-06-26. Imported into EnviroNearby November 5, 2026. How we use this data · Report a problem