Median AQI
41
Good
North Carolina · County air quality · 2025
Montgomery County, North Carolina
Median AQI 41 (Good). 78.6% of monitored days rated Good, direct from EPA Air Quality System stations.
- 41
- Median AQI
- 78.6%
- Good-air days
- 0
- Unhealthy days
- 48%
- Cleaner than US counties
The verdict
According to EPA Air Quality System monitoring data, Montgomery County's air is good on balance, more polluted than the median US county, a median AQI of 41 with 78.6% of 271 monitored days in the Good band, driven mainly by PM2.5.
- 41
- median AQI · Good
- 78.6%
- days rated Good
- PM2.5
- main pollutant
- 48%
- cleaner than US counties
Not one day crossed into the Unhealthy tier; the worst single reading was AQI 85.
Data updated July 2026
- Good · 213 d · 78.6%
- Moderate · 58 d · 21.4%
How did Montgomery County's air break down in 2025?
Across 271 monitored days, 213 fell in the Good band (AQI 0–50) and 0 reached Unhealthy or worse. The worst single day peaked at AQI 85 (Moderate).
EPA AQS →Air quality data from EPA Air Quality System (2025). 271 days monitored. Median AQI: 41 (Good).
Insights: Montgomery County, North Carolina. EPA monitors recorded a median Air Quality Index of 41 across 271 measured days in 2025, earning a Good classification and a Good health grade. Of those days, 213 (79%) fell in the Good band (AQI 0–50), 58 (21%) registered Moderate readings, and 0 (0%) reached Unhealthy for Sensitive Groups. The 90th-percentile AQI settled at 54, while the worst single-day peak hit 85 (Moderate). Residents averaged about 23.6 clean-air days per 30-day window during the monitoring year.
The full pollutant mix ranks as PM2.5 (143 days), Ozone (128 days). Across the 2020–2025 trend window, good days shifted by -68 and the median AQI moved +1 points, placing the multi-year trajectory at stable. The worst single reading over the 2020–2025 window was AQI 85, moderate but never Unhealthy. Nearby counties show comparable readings: Alexander (92.4% good, AQI 39); Avery (93.9% good, AQI 38); Buncombe (71.4% good, AQI 42); Caldwell (96.2% good, AQI 37); Carteret (94.2% good, AQI 37); Caswell (94.6% good, AQI 39).
Air Quality Summary
Good Days
78.6%
213 of 271 monitored days
3.6pp vs 75% target
Max AQI Recorded
85
Moderate
Health Grade
Good
90th-pct AQI 54
Montgomery County, Good days share 78.6%
National avg
Share of monitored days at AQI 0-50 (Good band).
Montgomery County, Unhealthy-or-worse share 0.0%
National avg
Share of monitored days above AQI 150 (Unhealthy or worse). Bar maxes at 10% (worst-county ceiling).
AQI Day Breakdown (2025)
Distribution of 271 monitored days across EPA AQI categories.
Good
213
79%
Moderate
58
21%
USG
0
0%
Unhealthy
0
0%
Very Unhealthy
0
0%
Hazardous
0
0%
Pollutant Breakdown
Days where each pollutant was the primary driver of AQI readings in Montgomery County.
- PM2.5 · 143 days · 52.8%
- Ozone · 128 days · 47.2%
Health Impact Assessment
Good
Montgomery County's air quality is rated Good based on 78.6% good air days. No unhealthy air days were recorded in 2025.
Air quality was acceptable on 78.6% of monitored days in 2025, with a median AQI of 41. Unusually sensitive people can check real-time conditions at AirNow.gov during high-pollution events.
The dominant pollutant is PM2.5, driving AQI on 143 of 271 monitored days.
5-Year Air Quality Trend
Air quality is stable in Montgomery County. Best year: 2020 (281 good days).
| Year | Good | Moderate | USG | Unhealthy | Median AQI | Max AQI |
|---|---|---|---|---|---|---|
| 2020 | 281 | 85 | 0 | 0 | 40 | 85 |
| 2021 | 257 | 108 | 0 | 0 | 43 | 80 |
| 2022 | 263 | 100 | 0 | 0 | 43 | 80 |
| 2023 | 200 | 160 | 3 | 0 | 48 | 134 |
| 2024 | 257 | 109 | 0 | 0 | 42 | 83 |
| 2025 | 213 | 58 | 0 | 0 | 41 | 85 |
How does Montgomery County compare?
How Montgomery County compares
Good-day share better than US avg
Montgomery County 78.6%
Alexander County, North Carolina 92.4%
US average 76.5%
Median AQI worse than US avg
Montgomery County 41
Alexander County, North Carolina 39
US average 38
Unhealthy days / yr about average
Montgomery County 0
Alexander County, North Carolina 0
US average 0
Other Counties in North Carolina
Air quality comparison for nearby counties in North Carolina.
Counties with Similar Air Quality
Counties across the US with a similar median AQI to Montgomery County.
Albemarle County, Virginia
AQI 41 · 77.9% good
Anderson County, South Carolina
AQI 41 · 90.0% good
Berkshire County, Massachusetts
AQI 41 · 71.6% good
Berrien County, Michigan
AQI 41 · 80.9% good
Blair County, Pennsylvania
AQI 41 · 71.9% good
Bonner County, Idaho
AQI 41 · 71.3% good
What Montgomery County's air means for you
The air here stays in the breathable range year-round, with PM2.5 the main thing to watch.
- Sensitive groups (asthma, heart conditions, children, older adults) should check the AQI on high-PM2.5 days, the guide explains what a median of 41 means for exposure. Health guidance
- See how Montgomery County ranks against every monitored U.S. county on Good-day share. County rankings
- Compare Montgomery County with its North Carolina neighbours before drawing a conclusion about the region. All of North Carolina
Based on 271 EPA-monitored days in 2025; figures reflect only days the monitors reported. Source: EPA Air Quality System annual summaries.
More Air Quality Data
Air Quality Guides
Frequently Asked Questions
What is the air quality in Montgomery County, North Carolina? ▼
Montgomery County has a median Air Quality Index (AQI) of 41, rated "Good." 78.6% of monitored days (213 out of 271) had good air quality in 2025.
What is the main pollutant in Montgomery County? ▼
The primary pollutant in Montgomery County is Fine Particles (PM2.5), which was the main AQI driver on 143 days (53% of monitored days). Penetrates deep into lungs and bloodstream. Linked to heart disease and premature death.
How many unhealthy air days does Montgomery County have? ▼
In 2025, Montgomery County recorded 0 unhealthy air days (0 Unhealthy, 0 Very Unhealthy, 0 Hazardous). The maximum AQI reached 85.
Is the air quality in Montgomery County getting better or worse? ▼
Air quality in Montgomery County is stable based on 5-year trends (2020-2025). Best year: 2020 with 281 good days. Worst year: 2023 with 200 good days.
What does AQI 41 mean for health? ▼
Montgomery County's median AQI of 41 falls in the "Good" category. See the <a href="/guides/understanding-aqi" class="underline">AQI category guide</a> for what each range means for health.
How does Montgomery County compare to other counties in North Carolina? ▼
Montgomery County has 78.6% good air days. Nearby counties in North Carolina: Alexander (92.4% good), Avery (93.9% good), Buncombe (71.4% good), Caldwell (96.2% good), Carteret (94.2% good), Caswell (94.6% good).
What is the 90th percentile AQI in Montgomery County? ▼
The 90th percentile AQI for Montgomery County is 54, meaning 90% of monitored days had an AQI at or below this level. The maximum AQI recorded was 85 (Moderate).
Data Sources
Primary Source: U.S. Environmental Protection Agency (EPA), Air Quality System (AQS), Annual AQI by County dataset, 2020–2025 (aqs.epa.gov). For current conditions (not shown here — this page is historical annual data), see EPA AirNow (airnow.gov). See our methodology for how AQI, median, and coverage figures are computed.
Informational only, not professional advice. Data from EPA AQS. See our disclaimer.
Every figure on PlainAir is rendered directly from EPA AQS air-quality monitoring data, no number is typed in by an editor. This page draws directly on EPA AQS air-quality monitoring data, no figure is typed in by an editor. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error.