Median AQI
37
Good
North Carolina · County air quality · 2025
Caswell County, North Carolina
Median AQI 37 (Good). 95.1% of monitored days rated Good, direct from EPA Air Quality System stations.
- 37
- Median AQI
- 95.1%
- Good-air days
- 0
- Unhealthy days
- 92%
- Cleaner than US counties
Caswell County's 2025 annual median AQI is 37 (Good), with 95.1% Good days
According to the U.S. EPA Air Quality System, Caswell County, North Carolina posted a 2025 median AQI of 37 (Good) across 245 monitored days, with 95.1% 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
- Caswell County's 95.1% Good-day share places it cleaner than 92% of US counties in 2025.
- Closest median-AQI peer
- Alachua County (88.7% Good, median AQI 37) is the closest nationwide median-AQI peer to Caswell County.
- 2020–2025 trend
- Caswell County's floor-qualifying Good-day share is worsening from 2020 to 2025 (98.6% → 95.1%).
- Median AQI
- Median AQI: 37
The verdict
According to EPA Air Quality System monitoring data, Caswell County's air is good on balance, among the cleanest 10% of US counties, a median AQI of 37 with 95.1% of 245 monitored days in the Good band, driven mainly by Ozone.
- 37
- median AQI · Good
- 95.1%
- days rated Good
- Ozone
- main pollutant
- 92%
- cleaner than US counties
Not one day crossed into the Unhealthy tier; the worst single reading was AQI 77.
Annual release change
What changed in the 2025 EPA annual release
- Caswell County's Good-day share rose from 92.2% to 95.1% between the 2024 and 2025 EPA annual releases, a change of +2.9 percentage points.
Data updated August 2026
- Good · 233 d · 95.1%
- Moderate · 12 d · 4.9%
How did Caswell County's air break down in 2025?
Across 245 monitored days, 233 fell in the Good band (AQI 0–50) and 0 reached Unhealthy or worse. The worst single day peaked at AQI 77 (Moderate).
EPA AQS →Air quality data from EPA Air Quality System (2025). 245 days monitored. Median AQI: 37 (Good).
Insights: Caswell County, North Carolina. EPA monitors recorded a median Air Quality Index of 37 across 245 measured days in 2025, earning a Good classification and a Excellent health grade. Of those days, 233 (95%) fell in the Good band (AQI 0–50), 12 (5%) registered Moderate readings, and 0 (0%) reached Unhealthy for Sensitive Groups. The 90th-percentile AQI settled at 47, while the worst single-day peak hit 77 (Moderate). Residents averaged about 28.5 clean-air days per 30-day window during the monitoring year.
The full pollutant mix ranks as Ozone (245 days). Across the 2020–2025 trend window, the share of monitored days rated Good shifted by -3.5 points (measured against 354 monitored days in 2020 and 245 in 2025, so raw day counts are not comparable) and the median AQI moved +6 points, placing the multi-year trajectory at worsening. The worst single reading over the 2020–2025 window was AQI 77, 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); Catawba (68.9% good, AQI 42).
Air Quality Summary
Good Days
95.1%
233 of 245 monitored days
20.1pp vs 75% target
Max AQI Recorded
77
Moderate
Health Grade
Excellent
90th-pct AQI 47
Caswell County, Good days share 95.1%
National avg
Share of monitored days at AQI 0-50 (Good band).
Caswell 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 245 monitored days across EPA AQI categories.
Good
233
95%
Moderate
12
5%
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 Caswell County.
- Ozone · 245 days · 100.0%
Health Impact Assessment
Excellent
Caswell County's air quality is rated Excellent based on 95.1% good air days. No unhealthy air days were recorded in 2025.
Air quality was acceptable on 95.1% of monitored days in 2025, with a median AQI of 37. Unusually sensitive people can check real-time conditions at AirNow.gov during high-pollution events.
The dominant pollutant is Ozone, driving AQI on 245 of 245 monitored days.
5-Year Air Quality Trend
Air quality is worsening in Caswell County. Highest Good-day share: 2020 (98.6%, 349 of 354 monitored days).
| Year | Good | Moderate | USG | Unhealthy | Median AQI | Max AQI |
|---|---|---|---|---|---|---|
| 2020 | 349 | 5 | 0 | 0 | 31 | 61 |
| 2021 | 240 | 10 | 0 | 0 | 38 | 80 |
| 2022 | 253 | 11 | 0 | 0 | 39 | 64 |
| 2023 | 325 | 25 | 0 | 0 | 36 | 97 |
| 2024 | 225 | 19 | 0 | 0 | 38 | 84 |
| 2025 | 233 | 12 | 0 | 0 | 37 | 77 |
How does Caswell County compare?
How Caswell County compares
Good-day share better than typical
Caswell County 95.1%
Alachua County, Florida 88.7%
Typical US county 76.0%
Median AQI better than typical
Caswell County 37
Alachua County, Florida 37
Typical US county 39
Unhealthy days / yr better than typical
Caswell County 0
Alachua County, Florida 0
Typical US county 1
Counties with a similar median AQI
Nationwide peers within about the same annual median AQI as Caswell County (37), not geographic neighbors.
Alachua County, Florida
Median AQI 37 · 88.7% Good-day share
Arlington County, Virginia
Median AQI 37 · 87.4% Good-day share
Bennington County, Vermont
Median AQI 37 · 83.6% Good-day share
Boone County, Missouri
Median AQI 37 · 93.2% Good-day share
Bradford County, Pennsylvania
Median AQI 37 · 81.6% Good-day share
Brown County, Wisconsin
Median AQI 37 · 73.2% 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).
Dawson County, Georgia
95.1% Good-day share · median AQI 34
Rockingham County, North Carolina
95.1% Good-day share · median AQI 38
Lee County, Mississippi
95.0% Good-day share · median AQI 38
Lake County, Florida
95.0% Good-day share · median AQI 35
Highlands County, Florida
94.9% Good-day share · median AQI 35
Washington County, Minnesota
94.9% Good-day share · median AQI 34
North Carolina counties on the map
Geographic containment only, other monitored counties in North Carolina, independent of AQI or pollutant match.
What Caswell 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 37 means for exposure. Health guidance
- See how Caswell County ranks against every monitored U.S. county on Good-day share. County rankings
- Compare Caswell County with its North Carolina neighbours before drawing a conclusion about the region. All of North Carolina
Based on 245 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 Caswell County, North Carolina? ▼
Caswell County has a median Air Quality Index (AQI) of 37, rated "Good." 95.1% of monitored days (233 out of 245) had good air quality in 2025.
What is the main pollutant in Caswell County? ▼
The primary pollutant in Caswell County is Ozone (O3), which was the main AQI driver on 245 days (100% of monitored days). Can trigger asthma, reduce lung function, and cause chest pain.
How many unhealthy air days does Caswell County have? ▼
In 2025, Caswell County recorded 0 unhealthy air days (0 Unhealthy, 0 Very Unhealthy, 0 Hazardous). The maximum AQI reached 77.
Is the air quality in Caswell County getting better or worse? ▼
Air quality in Caswell 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 98.6% (349 of 354 days). Lowest qualifying Good-day share: 2024 at 92.2% (225 of 244 days).
What does AQI 37 mean for health? ▼
Caswell County's median AQI of 37 falls in the "Good" category. See the AQI category guide for what each range means for health.
How does Caswell County compare to other counties in North Carolina? ▼
Caswell County has 95.1% 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), Catawba (68.9% good).
What is the 90th percentile AQI in Caswell County? ▼
The 90th percentile AQI for Caswell County is 47, meaning 90% of monitored days had an AQI at or below this level. The maximum AQI recorded was 77 (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 Caswell 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.