Median AQI
41
Good
Georgia · County air quality · 2025
Glynn County, Georgia
Median AQI 41 (Good). 74.3% of monitored days rated Good, direct from EPA Air Quality System stations.
- 41
- Median AQI
- 74.3%
- Good-air days
- 0
- Unhealthy days
- 43%
- Cleaner than US counties
Glynn County's 2025 annual median AQI is 41 (Good), with 74.3% Good days
According to the U.S. EPA Air Quality System, Glynn County, Georgia posted a 2025 median AQI of 41 (Good) across 343 monitored days, with 74.3% 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
- Glynn County's 74.3% Good-day share places it cleaner than 43% of US counties in 2025.
- Closest median-AQI peer
- Armstrong County (70.5% Good, median AQI 41) is the closest nationwide median-AQI peer to Glynn County.
- 2020–2025 trend
- Glynn County's floor-qualifying Good-day share is worsening from 2020 to 2025 (89.8% → 74.3%).
- Median AQI
- Median AQI: 41
The verdict
According to EPA Air Quality System monitoring data, Glynn County's air is good on balance, more polluted than the median US county, a median AQI of 41 with 74.3% of 343 monitored days in the Good band, driven mainly by PM2.5.
- 41
- median AQI · Good
- 74.3%
- days rated Good
- PM2.5
- main pollutant
- 43%
- cleaner than US counties
Not one day crossed into the Unhealthy tier; the worst single reading was AQI 94.
Annual release change
What changed in the 2025 EPA annual release
- Glynn County's Good-day share fell from 78.1% to 74.3% between the 2024 and 2025 EPA annual releases, a change of -3.8 percentage points.
- Glynn County's peak single-day AQI rose from 84 to 94 between the 2024 and 2025 EPA annual releases, a change of +10 points.
Data updated August 2026
- Good · 255 d · 74.3%
- Moderate · 88 d · 25.7%
How did Glynn County's air break down in 2025?
Across 343 monitored days, 255 fell in the Good band (AQI 0–50) and 0 reached Unhealthy or worse. The worst single day peaked at AQI 94 (Moderate).
EPA AQS →Air quality data from EPA Air Quality System (2025). 343 days monitored. Median AQI: 41 (Good).
Insights: Glynn County, Georgia. EPA monitors recorded a median Air Quality Index of 41 across 343 measured days in 2025, earning a Good classification and a Moderate health grade. Of those days, 255 (74%) fell in the Good band (AQI 0–50), 88 (26%) registered Moderate readings, and 0 (0%) reached Unhealthy for Sensitive Groups. The 90th-percentile AQI settled at 57, while the worst single-day peak hit 94 (Moderate). Residents averaged about 22.3 clean-air days per 30-day window during the monitoring year.
The full pollutant mix ranks as PM2.5 (227 days), Ozone (116 days). Across the 2020–2025 trend window, the share of monitored days rated Good shifted by -15.5 points (measured against 285 monitored days in 2020 and 343 in 2025, so raw day counts are not comparable) and the median AQI moved +8 points, placing the multi-year trajectory at worsening. The worst single reading over the 2020–2025 window was AQI 94, moderate but never Unhealthy. Nearby counties show comparable readings: Bibb (42.7% good, AQI 52); Charlton (92.6% good, AQI 27); Chatham (58.6% good, AQI 47); Chattooga (96.3% good, AQI 39); Clarke (57.8% good, AQI 46); Clayton (54.1% good, AQI 48).
Air Quality Summary
Good Days
74.3%
255 of 343 monitored days
-0.7pp vs 75% target
Max AQI Recorded
94
Moderate
Health Grade
Moderate
90th-pct AQI 57
Glynn County, Good days share 74.3%
National avg
Share of monitored days at AQI 0-50 (Good band).
Glynn 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 343 monitored days across EPA AQI categories.
Good
255
74%
Moderate
88
26%
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 Glynn County.
- PM2.5 · 227 days · 66.2%
- Ozone · 116 days · 33.8%
Health Impact Assessment
Moderate
Glynn County's air quality is rated Moderate based on 74.3% good air days. No unhealthy air days were recorded in 2025.
Air quality was acceptable on 74.3% 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 227 of 343 monitored days.
5-Year Air Quality Trend
Air quality is worsening in Glynn County. Highest Good-day share: 2020 (89.8%, 256 of 285 monitored days).
| Year | Good | Moderate | USG | Unhealthy | Median AQI | Max AQI |
|---|---|---|---|---|---|---|
| 2020 | 256 | 29 | 0 | 0 | 33 | 97 |
| 2021 | 267 | 55 | 0 | 0 | 38 | 80 |
| 2022 | 221 | 134 | 1 | 0 | 45 | 106 |
| 2023 | 243 | 120 | 0 | 0 | 43 | 90 |
| 2024 | 286 | 80 | 0 | 0 | 39 | 84 |
| 2025 | 255 | 88 | 0 | 0 | 41 | 94 |
How does Glynn County compare?
How Glynn County compares
Good-day share worse than US avg
Glynn County 74.3%
Armstrong County, Pennsylvania 70.5%
US average 76.0%
Median AQI worse than US avg
Glynn County 41
Armstrong County, Pennsylvania 41
US average 39
Unhealthy days / yr better than US avg
Glynn County 0
Armstrong County, Pennsylvania 0
US average 1
Counties with a similar median AQI
Nationwide peers within about the same annual median AQI as Glynn County (41), not geographic neighbors.
Armstrong County, Pennsylvania
Median AQI 41 · 70.5% Good-day share
Benewah County, Idaho
Median AQI 41 · 63.4% Good-day share
Berrien County, Michigan
Median AQI 41 · 80.9% Good-day share
Callaway County, Missouri
Median AQI 41 · 89.6% Good-day share
Cambria County, Pennsylvania
Median AQI 41 · 74.5% Good-day share
Cass County, Missouri
Median AQI 41 · 77.6% 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).
Madison County, Tennessee
74.3% Good-day share · median AQI 36
Marion County, West Virginia
74.2% Good-day share · median AQI 37
McCracken County, Kentucky
74.5% Good-day share · median AQI 41
Becker County, Minnesota
74.0% Good-day share · median AQI 38
Frederick County, Virginia
74.0% Good-day share · median AQI 39
Richmond County, New York
74.0% Good-day share · median AQI 41
Georgia counties on the map
Geographic containment only, other monitored counties in Georgia, independent of AQI or pollutant match.
What Glynn 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 Glynn County ranks against every monitored U.S. county on Good-day share. County rankings
- Compare Glynn County with its Georgia neighbours before drawing a conclusion about the region. All of Georgia
Based on 343 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 Glynn County, Georgia? ▼
Glynn County has a median Air Quality Index (AQI) of 41, rated "Good." 74.3% of monitored days (255 out of 343) had good air quality in 2025.
What is the main pollutant in Glynn County? ▼
The primary pollutant in Glynn County is Fine Particles (PM2.5), which was the main AQI driver on 227 days (66% of monitored days). Penetrates deep into lungs and bloodstream. Linked to heart disease and premature death.
How many unhealthy air days does Glynn County have? ▼
In 2025, Glynn County recorded 0 unhealthy air days (0 Unhealthy, 0 Very Unhealthy, 0 Hazardous). The maximum AQI reached 94.
Is the air quality in Glynn County getting better or worse? ▼
Air quality in Glynn 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 89.8% (256 of 285 days). Lowest qualifying Good-day share: 2022 at 62.1% (221 of 356 days).
What does AQI 41 mean for health? ▼
Glynn County's median AQI of 41 falls in the "Good" category. See the AQI category guide for what each range means for health.
How does Glynn County compare to other counties in Georgia? ▼
Glynn County has 74.3% good air days. Nearby counties in Georgia: Bibb (42.7% good), Charlton (92.6% good), Chatham (58.6% good), Chattooga (96.3% good), Clarke (57.8% good), Clayton (54.1% good).
What is the 90th percentile AQI in Glynn County? ▼
The 90th percentile AQI for Glynn County is 57, meaning 90% of monitored days had an AQI at or below this level. The maximum AQI recorded was 94 (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 Glynn County, Georgia · 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.