Median AQI
33
Good
North Carolina · County air quality · 2025
Northampton County, North Carolina
Median AQI 33 (Good). 78.1% of monitored days rated Good, direct from EPA Air Quality System stations.
- 33
- Median AQI
- 78.1%
- Good-air days
- 0
- Unhealthy days
- 51%
- Cleaner than US counties
Northampton County's 2025 annual median AQI is 33 (Good), with 78.1% Good days
According to the U.S. EPA Air Quality System, Northampton County, North Carolina posted a 2025 median AQI of 33 (Good) across 351 monitored days, with 78.1% 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
- Northampton County's 78.1% Good-day share places it cleaner than 51% of US counties in 2025.
- Closest median-AQI peer
- Apache County (86.2% Good, median AQI 33) is the closest nationwide median-AQI peer to Northampton County.
- 2020–2025 trend
- Northampton County's floor-qualifying Good-day share is worsening from 2020 to 2025 (84.2% → 78.1%).
- Median AQI
- Median AQI: 33
The verdict
According to EPA Air Quality System monitoring data, Northampton County's air is good on balance, cleaner than the median US county, a median AQI of 33 with 78.1% of 351 monitored days in the Good band, driven mainly by PM2.5.
- 33
- median AQI · Good
- 78.1%
- days rated Good
- PM2.5
- main pollutant
- 51%
- cleaner than US counties
Not one day crossed into the Unhealthy tier; the worst single reading was AQI 79.
Data updated August 2026
- Good · 274 d · 78.1%
- Moderate · 77 d · 21.9%
How did Northampton County's air break down in 2025?
Across 351 monitored days, 274 fell in the Good band (AQI 0–50) and 0 reached Unhealthy or worse. The worst single day peaked at AQI 79 (Moderate).
EPA AQS →Air quality data from EPA Air Quality System (2025). 351 days monitored. Median AQI: 33 (Good).
Insights: Northampton County, North Carolina. EPA monitors recorded a median Air Quality Index of 33 across 351 measured days in 2025, earning a Good classification and a Good health grade. Of those days, 274 (78%) fell in the Good band (AQI 0–50), 77 (22%) registered Moderate readings, and 0 (0%) reached Unhealthy for Sensitive Groups. The 90th-percentile AQI settled at 55, while the worst single-day peak hit 79 (Moderate). Residents averaged about 23.4 clean-air days per 30-day window during the monitoring year.
The full pollutant mix ranks as PM2.5 (351 days). Across the 2020–2025 trend window, the share of monitored days rated Good shifted by -6.1 points and the median AQI moved +4 points, placing the multi-year trajectory at worsening. The worst single reading over the 2020–2025 window was AQI 79, 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
78.1%
274 of 351 monitored days
3.1pp vs 75% target
Max AQI Recorded
79
Moderate
Health Grade
Good
90th-pct AQI 55
Northampton County, Good days share 78.1%
National avg
Share of monitored days at AQI 0-50 (Good band).
Northampton 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 351 monitored days across EPA AQI categories.
Good
274
78%
Moderate
77
22%
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 Northampton County.
- PM2.5 · 351 days · 100.0%
Health Impact Assessment
Good
Northampton County's air quality is rated Good based on 78.1% good air days. No unhealthy air days were recorded in 2025.
Air quality was acceptable on 78.1% of monitored days in 2025, with a median AQI of 33. Unusually sensitive people can check real-time conditions at AirNow.gov during high-pollution events.
The dominant pollutant is PM2.5, driving AQI on 351 of 351 monitored days.
5-Year Air Quality Trend
Air quality is worsening in Northampton County. Highest Good-day share: 2020 (84.2%, 303 of 360 monitored days).
| Year | Good | Moderate | USG | Unhealthy | Median AQI | Max AQI |
|---|---|---|---|---|---|---|
| 2020 | 303 | 57 | 0 | 0 | 29 | 90 |
| 2021 | 270 | 93 | 0 | 0 | 34 | 94 |
| 2022 | 284 | 78 | 0 | 0 | 33 | 71 |
| 2023 | 256 | 108 | 1 | 0 | 37 | 134 |
| 2024 | 289 | 77 | 0 | 0 | 32 | 82 |
| 2025 | 274 | 77 | 0 | 0 | 33 | 79 |
How does Northampton County compare?
How Northampton County compares
Good-day share better than US avg
Northampton County 78.1%
Apache County, Arizona 86.2%
US average 76.0%
Median AQI better than US avg
Northampton County 33
Apache County, Arizona 33
US average 39
Unhealthy days / yr better than US avg
Northampton County 0
Apache County, Arizona 0
US average 1
Counties with a similar median AQI
Nationwide peers within about the same annual median AQI as Northampton County (33), not geographic neighbors.
Apache County, Arizona
Median AQI 33 · 86.2% Good-day share
Ascension County, Louisiana
Median AQI 33 · 95.6% Good-day share
Carlton County, Minnesota
Median AQI 33 · 82.8% Good-day share
Clark County, Illinois
Median AQI 33 · 93.8% Good-day share
Clark County, Washington
Median AQI 33 · 82.7% Good-day share
Clay County, Alabama
Median AQI 33 · 81.1% Good-day share
Same primary pollutant: PM2.5
PM2.5 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).
Humboldt County, California
78.1% Good-day share · median AQI 38
Sumter County, Alabama
78.0% Good-day share · median AQI 41
Bristol City County, Virginia
78.0% Good-day share · median AQI 34
McMinn County, Tennessee
78.2% Good-day share · median AQI 37
Codington County, South Dakota
78.0% Good-day share · median AQI 35
Siskiyou County, California
78.2% 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 Northampton 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 33 means for exposure. Health guidance
- See how Northampton County ranks against every monitored U.S. county on Good-day share. County rankings
- Compare Northampton County with its North Carolina neighbours before drawing a conclusion about the region. All of North Carolina
Based on 351 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 Northampton County, North Carolina? ▼
Northampton County has a median Air Quality Index (AQI) of 33, rated "Good." 78.1% of monitored days (274 out of 351) had good air quality in 2025.
What is the main pollutant in Northampton County? ▼
The primary pollutant in Northampton County is Fine Particles (PM2.5), which was the main AQI driver on 351 days (100% of monitored days). Penetrates deep into lungs and bloodstream. Linked to heart disease and premature death.
How many unhealthy air days does Northampton County have? ▼
In 2025, Northampton County recorded 0 unhealthy air days (0 Unhealthy, 0 Very Unhealthy, 0 Hazardous). The maximum AQI reached 79.
Is the air quality in Northampton County getting better or worse? ▼
Air quality in Northampton 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 84.2% (303 of 360 days). Lowest qualifying Good-day share: 2023 at 70.1% (256 of 365 days).
What does AQI 33 mean for health? ▼
Northampton County's median AQI of 33 falls in the "Good" category. See the AQI category guide for what each range means for health.
How does Northampton County compare to other counties in North Carolina? ▼
Northampton County has 78.1% 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), Caswell (95.1% good).
What is the 90th percentile AQI in Northampton County? ▼
The 90th percentile AQI for Northampton County is 55, meaning 90% of monitored days had an AQI at or below this level. The maximum AQI recorded was 79 (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 Northampton County, North Carolina · 2020–2025
Share this annual record
Send the source-year summary or download its ready-to-use data card.
Download this county's annual AQI row as CSV , with the same EPA fields and denominator shown on this page.
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.