Median AQI
45
Good
North Carolina · County air quality · 2025
Forsyth County, North Carolina
Median AQI 45 (Good). 63.6% of monitored days rated Good, direct from EPA Air Quality System stations.
- 45
- Median AQI
- 63.6%
- Good-air days
- 0
- Unhealthy days
- 20%
- Cleaner than US counties
Forsyth County's 2025 annual median AQI is 45 (Good), with 63.6% Good days
According to the U.S. EPA Air Quality System, Forsyth County, North Carolina posted a 2025 median AQI of 45 (Good) across 365 monitored days, with 63.6% 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
- Forsyth County's 63.6% Good-day share places it cleaner than 20% of US counties in 2025.
- Closest median-AQI peer
- Baltimore County (64.7% Good, median AQI 45) is the closest nationwide median-AQI peer to Forsyth County.
- 2020–2025 trend
- Forsyth County's floor-qualifying Good-day share is stable from 2020 to 2025 (63.7% → 63.6%).
- Median AQI
- Median AQI: 45
The verdict
According to EPA Air Quality System monitoring data, Forsyth County's air is good on balance, among the more polluted 10% of US counties, a median AQI of 45 with 63.6% of 365 monitored days in the Good band, driven mainly by PM2.5.
- 45
- median AQI · Good
- 63.6%
- days rated Good
- PM2.5
- main pollutant
- 20%
- cleaner than US counties
Not one day crossed into the Unhealthy tier; the worst single reading was AQI 100.
Annual release change
What changed in the 2025 EPA annual release
- Forsyth County's Good-day share rose from 57.4% to 63.6% between the 2024 and 2025 EPA annual releases, a change of +6.2 percentage points.
- Forsyth County's peak single-day AQI fell from 122 to 100 between the 2024 and 2025 EPA annual releases, a change of -22 points.
Data updated August 2026
- Good · 232 d · 63.6%
- Moderate · 133 d · 36.4%
How did Forsyth County's air break down in 2025?
Across 365 monitored days, 232 fell in the Good band (AQI 0–50) and 0 reached Unhealthy or worse. The worst single day peaked at AQI 100 (Moderate).
EPA AQS →Air quality data from EPA Air Quality System (2025). 365 days monitored. Median AQI: 45 (Good).
Insights: Forsyth County, North Carolina. EPA monitors recorded a median Air Quality Index of 45 across 365 measured days in 2025, earning a Good classification and a Moderate health grade. Of those days, 232 (64%) fell in the Good band (AQI 0–50), 133 (36%) registered Moderate readings, and 0 (0%) reached Unhealthy for Sensitive Groups. The 90th-percentile AQI settled at 63, while the worst single-day peak hit 100 (Moderate). Residents averaged about 19.1 clean-air days per 30-day window during the monitoring year.
The full pollutant mix ranks as PM2.5 (208 days), Ozone (154 days), NO2 (3 days). Across the 2020–2025 trend window, the share of monitored days rated Good shifted by -0.1 points and the median AQI moved +0 points, placing the multi-year trajectory at stable. The worst single reading over the 2020–2025 window was AQI 100, 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
63.6%
232 of 365 monitored days
-11.4pp vs 75% target
Max AQI Recorded
100
Moderate
Health Grade
Moderate
90th-pct AQI 63
Forsyth County, Good days share 63.6%
National avg
Share of monitored days at AQI 0-50 (Good band).
Forsyth 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 365 monitored days across EPA AQI categories.
Good
232
64%
Moderate
133
36%
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 Forsyth County.
- PM2.5 · 208 days · 57.0%
- Ozone · 154 days · 42.2%
- NO₂ · 3 days · 0.8%
Health Impact Assessment
Moderate
Forsyth County's air quality is rated Moderate based on 63.6% good air days. No unhealthy air days were recorded in 2025.
Air quality was acceptable on 63.6% of monitored days in 2025, with a median AQI of 45. Unusually sensitive people can check real-time conditions at AirNow.gov during high-pollution events.
The dominant pollutant is PM2.5, driving AQI on 208 of 365 monitored days.
5-Year Air Quality Trend
Air quality is stable in Forsyth County. Highest Good-day share: 2020 (63.7%, 233 of 366 monitored days).
| Year | Good | Moderate | USG | Unhealthy | Median AQI | Max AQI |
|---|---|---|---|---|---|---|
| 2020 | 233 | 133 | 0 | 0 | 45 | 97 |
| 2021 | 201 | 161 | 3 | 0 | 48 | 124 |
| 2022 | 209 | 155 | 1 | 0 | 48 | 137 |
| 2023 | 165 | 193 | 6 | 1 | 52 | 154 |
| 2024 | 210 | 152 | 4 | 0 | 47 | 122 |
| 2025 | 232 | 133 | 0 | 0 | 45 | 100 |
How does Forsyth County compare?
How Forsyth County compares
Good-day share worse than typical
Forsyth County 63.6%
Baltimore County, Maryland 64.7%
Typical US county 76.0%
Median AQI worse than typical
Forsyth County 45
Baltimore County, Maryland 45
Typical US county 39
Unhealthy days / yr better than typical
Forsyth County 0
Baltimore County, Maryland 0
Typical US county 1
Counties with a similar median AQI
Nationwide peers within about the same annual median AQI as Forsyth County (45), not geographic neighbors.
Baltimore County, Maryland
Median AQI 45 · 64.7% Good-day share
Bell County, Texas
Median AQI 45 · 66.0% Good-day share
Box Elder County, Utah
Median AQI 45 · 64.7% Good-day share
Bronx County, New York
Median AQI 45 · 59.2% Good-day share
Catano County, Puerto Rico
Median AQI 45 · 60.6% Good-day share
Catron County, New Mexico
Median AQI 45 · 71.7% 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).
Queens County, New York
63.6% Good-day share · median AQI 44
Summit County, Ohio
63.6% Good-day share · median AQI 44
Marshall County, West Virginia
63.7% Good-day share · median AQI 42
Benewah County, Idaho
63.4% Good-day share · median AQI 41
Mahoning County, Ohio
63.4% Good-day share · median AQI 44
Montgomery County, Alabama
63.8% Good-day share · median AQI 44
North Carolina counties on the map
Geographic containment only, other monitored counties in North Carolina, independent of AQI or pollutant match.
What Forsyth 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 45 means for exposure. Health guidance
- See how Forsyth County ranks against every monitored U.S. county on Good-day share. County rankings
- Compare Forsyth County with its North Carolina neighbours before drawing a conclusion about the region. All of North Carolina
Based on 365 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 Forsyth County, North Carolina? ▼
Forsyth County has a median Air Quality Index (AQI) of 45, rated "Good." 63.6% of monitored days (232 out of 365) had good air quality in 2025.
What is the main pollutant in Forsyth County? ▼
The primary pollutant in Forsyth County is Fine Particles (PM2.5), which was the main AQI driver on 208 days (57% of monitored days). Penetrates deep into lungs and bloodstream. Linked to heart disease and premature death.
How many unhealthy air days does Forsyth County have? ▼
In 2025, Forsyth County recorded 0 unhealthy air days (0 Unhealthy, 0 Very Unhealthy, 0 Hazardous). The maximum AQI reached 100.
Is the air quality in Forsyth County getting better or worse? ▼
Air quality in Forsyth County is stable 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 63.7% (233 of 366 days). Lowest qualifying Good-day share: 2023 at 45.2% (165 of 365 days).
What does AQI 45 mean for health? ▼
Forsyth County's median AQI of 45 falls in the "Good" category. See the AQI category guide for what each range means for health.
How does Forsyth County compare to other counties in North Carolina? ▼
Forsyth County has 63.6% 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 Forsyth County? ▼
The 90th percentile AQI for Forsyth County is 63, meaning 90% of monitored days had an AQI at or below this level. The maximum AQI recorded was 100 (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 Forsyth 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.