Median AQI
39
Good
North Carolina · County air quality · 2025
Granville County, North Carolina
Median AQI 39 (Good). 93.3% of monitored days rated Good, direct from EPA Air Quality System stations.
- 39
- Median AQI
- 93.3%
- Good-air days
- 0
- Unhealthy days
- 88%
- Cleaner than US counties
Granville County's 2025 annual median AQI is 39 (Good), with 93.3% Good days
According to the U.S. EPA Air Quality System, Granville County, North Carolina posted a 2025 median AQI of 39 (Good) across 238 monitored days, with 93.3% rated Good and 0 unhealthy or worse. This is an annual comparison, not today's advisory.
Data source EPA Air Quality System (AQS)
- Cleaner than US
- Granville County's 93.3% Good-day share places it cleaner than 88% of US counties in 2025.
- Closest median-AQI peer
- Aiken County (90.6% Good, median AQI 39) is the closest nationwide median-AQI peer to Granville County.
- 2020–2025 trend
- Granville County's floor-qualifying Good-day share is worsening from 2020 to 2025 (99.6% → 93.3%).
- Median AQI
- Median AQI: 39
The verdict
According to EPA Air Quality System monitoring data, Granville County's air is good on balance, cleaner than most US counties, a median AQI of 39 with 93.3% of 238 monitored days in the Good band, driven mainly by Ozone.
- 39
- median AQI · Good
- 93.3%
- days rated Good
- Ozone
- main pollutant
- 88%
- cleaner than US counties
Not one day crossed into the Unhealthy tier; the worst single reading was AQI 87.
Annual release change
What changed in the 2025 EPA annual release
- Granville County's Good-day share rose from 84.4% to 93.3% between the 2024 and 2025 EPA annual releases, a change of +8.9 percentage points.
- Granville County's peak single-day AQI fell from 101 to 87 between the 2024 and 2025 EPA annual releases, a change of -14 points.
- Granville County's median AQI fell from 42 to 39 between the 2024 and 2025 EPA annual releases, a change of -3 points.
Data updated August 2026
- Good · 222 d · 93.3%
- Moderate · 16 d · 6.7%
How did Granville County's air break down in 2025?
Across 238 monitored days, 222 fell in the Good band (AQI 0–50) and 0 reached Unhealthy or worse. The worst single day peaked at AQI 87 (Moderate).
EPA AQS →Air quality data from EPA Air Quality System (2025). 238 days monitored. Median AQI: 39 (Good).
Insights: Granville County, North Carolina. EPA monitors recorded a median Air Quality Index of 39 across 238 measured days in 2025, earning a Good classification and a Excellent health grade. Of those days, 222 (93%) fell in the Good band (AQI 0–50), 16 (7%) registered Moderate readings, and 0 (0%) reached Unhealthy for Sensitive Groups. The 90th-percentile AQI settled at 49, while the worst single-day peak hit 87 (Moderate). Residents averaged about 28.0 clean-air days per 30-day window during the monitoring year.
The full pollutant mix ranks as Ozone (238 days). Across the 2020–2025 trend window, the share of monitored days rated Good shifted by -6.3 points and the median AQI moved +3 points, placing the multi-year trajectory at worsening. The worst single reading over the 2020–2025 window was AQI 87, moderate but never Unhealthy. Nearby counties show comparable readings: Alexander (93.5% good, AQI 38); Avery (92.3% good, AQI 38); Buncombe (73.4% good, AQI 40); Caldwell (97.1% good, AQI 36); Carteret (96.2% good, AQI 35); Caswell (95.1% good, AQI 37).
Air Quality Summary
Good Days
93.3%
222 of 238 monitored days
18.3pp vs 75% target
Max AQI Recorded
87
Moderate
Health Grade
Excellent
90th-pct AQI 49
Granville County, Good days share 93.3%
National avg
Share of monitored days at AQI 0-50 (Good band).
Granville 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 238 monitored days across EPA AQI categories.
Good
222
93%
Moderate
16
7%
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 Granville County.
- Ozone · 238 days · 100.0%
Health Impact Assessment
Excellent
Granville County's air quality is rated Excellent based on 93.3% good air days. No unhealthy air days were recorded in 2025.
Air quality was acceptable on 93.3% of monitored days in 2025, with a median AQI of 39. Unusually sensitive people can check real-time conditions at AirNow.gov during high-pollution events.
The dominant pollutant is Ozone, driving AQI on 238 of 238 monitored days.
5-Year Air Quality Trend
Air quality is worsening in Granville County. Highest Good-day share: 2020 (99.6%, 237 of 238 monitored days).
| Year | Good | Moderate | USG | Unhealthy | Median AQI | Max AQI |
|---|---|---|---|---|---|---|
| 2020 | 237 | 1 | 0 | 0 | 36 | 51 |
| 2021 | 237 | 5 | 0 | 0 | 38 | 67 |
| 2022 | 223 | 20 | 1 | 0 | 42 | 112 |
| 2023 | 202 | 39 | 1 | 0 | 43 | 105 |
| 2024 | 206 | 37 | 1 | 0 | 42 | 101 |
| 2025 | 222 | 16 | 0 | 0 | 39 | 87 |
How does Granville County compare?
How Granville County compares
Good-day share better than US avg
Granville County 93.3%
Aiken County, South Carolina 90.6%
US average 76.0%
Median AQI about average
Granville County 39
Aiken County, South Carolina 39
US average 39
Unhealthy days / yr better than US avg
Granville County 0
Aiken County, South Carolina 0
US average 1
Counties with a similar median AQI
Nationwide peers within about the same annual median AQI as Granville County (39), not geographic neighbors.
Aiken County, South Carolina
Median AQI 39 · 90.6% Good-day share
Albany County, New York
Median AQI 39 · 68.5% Good-day share
Anderson County, Tennessee
Median AQI 39 · 94.3% Good-day share
Bay County, Michigan
Median AQI 39 · 70.4% Good-day share
Berkeley County, West Virginia
Median AQI 39 · 83.6% Good-day share
Boyd County, Kentucky
Median AQI 39 · 80.0% Good-day share
Same primary pollutant: Ozone
Ozone led the AQI on the most monitored days here. These peers share that driver and the closest Good-day share (a second relationship type beyond median-AQI neighbors).
Tompkins County, New York
93.2% Good-day share · median AQI 35
Berkeley County, South Carolina
93.3% Good-day share · median AQI 35
Boone County, Missouri
93.2% Good-day share · median AQI 37
Simpson County, Kentucky
93.4% Good-day share · median AQI 39
Wilson County, Tennessee
93.4% Good-day share · median AQI 38
La Crosse County, Wisconsin
93.4% Good-day share · median AQI 37
North Carolina counties on the map
Geographic containment only, other monitored counties in North Carolina, independent of AQI or pollutant match.
What Granville County's air means for you
The air here stays in the breathable range year-round, with Ozone the main thing to watch.
- Sensitive groups (asthma, heart conditions, children, older adults) should check the AQI on high-Ozone days, the guide explains what a median of 39 means for exposure. Health guidance
- See how Granville County ranks against every monitored U.S. county on Good-day share. County rankings
- Compare Granville County with its North Carolina neighbours before drawing a conclusion about the region. All of North Carolina
Based on 238 EPA-monitored days in 2025; figures reflect only days the monitors reported. Source: EPA Air Quality System annual summaries.
Keep exploring the annual AQI record
Air-quality reading list
Frequently Asked Questions
What is the air quality in Granville County, North Carolina? ▼
Granville County has a median Air Quality Index (AQI) of 39, rated "Good." 93.3% of monitored days (222 out of 238) had good air quality in 2025.
What is the main pollutant in Granville County? ▼
The primary pollutant in Granville County is Ozone (O3), which was the main AQI driver on 238 days (100% of monitored days). Can trigger asthma, reduce lung function, and cause chest pain.
How many unhealthy air days does Granville County have? ▼
In 2025, Granville County recorded 0 unhealthy air days (0 Unhealthy, 0 Very Unhealthy, 0 Hazardous). The maximum AQI reached 87.
Is the air quality in Granville County getting better or worse? ▼
Air quality in Granville County is worsening across floor-qualifying years (2020-2025); years with fewer than 100 monitored days are excluded from that direction. Highest qualifying Good-day share: 2020 at 99.6% (237 of 238 days). Lowest qualifying Good-day share: 2023 at 83.5% (202 of 242 days).
What does AQI 39 mean for health? ▼
Granville County's median AQI of 39 falls in the "Good" category. See the AQI category guide for what each range means for health.
How does Granville County compare to other counties in North Carolina? ▼
Granville County has 93.3% good air days. Nearby counties in North Carolina: Alexander (93.5% good), Avery (92.3% good), Buncombe (73.4% good), Caldwell (97.1% good), Carteret (96.2% good), Caswell (95.1% good).
What is the 90th percentile AQI in Granville County? ▼
The 90th percentile AQI for Granville County is 49, meaning 90% of monitored days had an AQI at or below this level. The maximum AQI recorded was 87 (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. Spotted a figure that looks wrong? Report a correction.
Source: U.S. EPA Air Quality System (AQS) Annual AQI by county summary files for Granville County, North Carolina · 2020–2025
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Every figure on PlainAirData 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.