Median AQI
45
Good
Mississippi · County air quality · 2025
Forrest County, Mississippi
Median AQI 45 (Good). 62.3% of monitored days rated Good, direct from EPA Air Quality System stations.
- 45
- Median AQI
- 62.3%
- Good-air days
- 0
- Unhealthy days
- 18%
- Cleaner than US counties
Forrest County's 2025 annual median AQI is 45 (Good), with 62.3% Good days
According to the U.S. EPA Air Quality System, Forrest County, Mississippi posted a 2025 median AQI of 45 (Good) across 363 monitored days, with 62.3% 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
- Forrest County's 62.3% Good-day share places it cleaner than 18% 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 Forrest County.
- 2020–2025 trend
- Forrest County's floor-qualifying Good-day share is improving from 2020 to 2025 (54.3% → 62.3%).
- Median AQI
- Median AQI: 45
The verdict
According to EPA Air Quality System monitoring data, Forrest County's air is good on balance, among the more polluted 10% of US counties, a median AQI of 45 with 62.3% of 363 monitored days in the Good band, driven mainly by PM2.5.
- 45
- median AQI · Good
- 62.3%
- days rated Good
- PM2.5
- main pollutant
- 18%
- cleaner than US counties
Not one day crossed into the Unhealthy tier; the worst single reading was AQI 97.
Annual release change
What changed in the 2025 EPA annual release
- Forrest County's Good-day share rose from 55.8% to 62.3% between the 2024 and 2025 EPA annual releases, a change of +6.5 percentage points.
Data updated August 2026
- Good · 226 d · 62.3%
- Moderate · 137 d · 37.7%
How did Forrest County's air break down in 2025?
Across 363 monitored days, 226 fell in the Good band (AQI 0–50) and 0 reached Unhealthy or worse. The worst single day peaked at AQI 97 (Moderate).
EPA AQS →Air quality data from EPA Air Quality System (2025). 363 days monitored. Median AQI: 45 (Good).
Insights: Forrest County, Mississippi. EPA monitors recorded a median Air Quality Index of 45 across 363 measured days in 2025, earning a Good classification and a Moderate health grade. Of those days, 226 (62%) fell in the Good band (AQI 0–50), 137 (38%) registered Moderate readings, and 0 (0%) reached Unhealthy for Sensitive Groups. The 90th-percentile AQI settled at 59, while the worst single-day peak hit 97 (Moderate). Residents averaged about 18.7 clean-air days per 30-day window during the monitoring year.
The full pollutant mix ranks as PM2.5 (363 days). Across the 2020–2025 trend window, the share of monitored days rated Good shifted by +8.0 points and the median AQI moved -3 points, placing the multi-year trajectory at improving. The worst single reading over the 2020–2025 window was AQI 97, moderate but never Unhealthy. Nearby counties show comparable readings: Bolivar (71.9% good, AQI 43); DeSoto (69.0% good, AQI 43); Hancock (70.1% good, AQI 43); Harrison (69.0% good, AQI 43); Hinds (45.8% good, AQI 52); Jackson (69.9% good, AQI 44).
Air Quality Summary
Good Days
62.3%
226 of 363 monitored days
-12.7pp vs 75% target
Max AQI Recorded
97
Moderate
Health Grade
Moderate
90th-pct AQI 59
Forrest County, Good days share 62.3%
National avg
Share of monitored days at AQI 0-50 (Good band).
Forrest 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 363 monitored days across EPA AQI categories.
Good
226
62%
Moderate
137
38%
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 Forrest County.
- PM2.5 · 363 days · 100.0%
Health Impact Assessment
Moderate
Forrest County's air quality is rated Moderate based on 62.3% good air days. No unhealthy air days were recorded in 2025.
Air quality was acceptable on 62.3% 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 363 of 363 monitored days.
5-Year Air Quality Trend
Air quality is improving in Forrest County. Highest Good-day share: 2025 (62.3%, 226 of 363 monitored days).
| Year | Good | Moderate | USG | Unhealthy | Median AQI | Max AQI |
|---|---|---|---|---|---|---|
| 2020 | 196 | 165 | 0 | 0 | 48 | 97 |
| 2021 | 178 | 185 | 0 | 0 | 51 | 93 |
| 2022 | 178 | 186 | 1 | 0 | 51 | 105 |
| 2023 | 145 | 220 | 0 | 0 | 53 | 94 |
| 2024 | 202 | 159 | 1 | 0 | 47 | 103 |
| 2025 | 226 | 137 | 0 | 0 | 45 | 97 |
How does Forrest County compare?
How Forrest County compares
Good-day share worse than US avg
Forrest County 62.3%
Baltimore County, Maryland 64.7%
US average 76.0%
Median AQI worse than US avg
Forrest County 45
Baltimore County, Maryland 45
US average 39
Unhealthy days / yr better than US avg
Forrest County 0
Baltimore County, Maryland 0
US average 1
Counties with a similar median AQI
Nationwide peers within about the same annual median AQI as Forrest 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).
Jackson County, Arkansas
62.3% Good-day share · median AQI 46
Calcasieu County, Louisiana
62.2% Good-day share · median AQI 47
Jefferson County, Louisiana
62.2% Good-day share · median AQI 47
Ouachita County, Louisiana
62.2% Good-day share · median AQI 45
Dauphin County, Pennsylvania
62.5% Good-day share · median AQI 44
Milwaukee County, Wisconsin
62.5% Good-day share · median AQI 43
Mississippi counties on the map
Geographic containment only, other monitored counties in Mississippi, independent of AQI or pollutant match.
What Forrest 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 Forrest County ranks against every monitored U.S. county on Good-day share. County rankings
- Compare Forrest County with its Mississippi neighbours before drawing a conclusion about the region. All of Mississippi
Based on 363 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 Forrest County, Mississippi? ▼
Forrest County has a median Air Quality Index (AQI) of 45, rated "Good." 62.3% of monitored days (226 out of 363) had good air quality in 2025.
What is the main pollutant in Forrest County? ▼
The primary pollutant in Forrest County is Fine Particles (PM2.5), which was the main AQI driver on 363 days (100% of monitored days). Penetrates deep into lungs and bloodstream. Linked to heart disease and premature death.
How many unhealthy air days does Forrest County have? ▼
In 2025, Forrest County recorded 0 unhealthy air days (0 Unhealthy, 0 Very Unhealthy, 0 Hazardous). The maximum AQI reached 97.
Is the air quality in Forrest County getting better or worse? ▼
Air quality in Forrest County is improving across floor-qualifying years (2020-2025); years with fewer than 100 monitored days are excluded from that direction. Highest qualifying Good-day share: 2025 at 62.3% (226 of 363 days). Lowest qualifying Good-day share: 2023 at 39.7% (145 of 365 days).
What does AQI 45 mean for health? ▼
Forrest 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 Forrest County compare to other counties in Mississippi? ▼
Forrest County has 62.3% good air days. Nearby counties in Mississippi: Bolivar (71.9% good), DeSoto (69.0% good), Hancock (70.1% good), Harrison (69.0% good), Hinds (45.8% good), Jackson (69.9% good).
What is the 90th percentile AQI in Forrest County? ▼
The 90th percentile AQI for Forrest County is 59, meaning 90% of monitored days had an AQI at or below this level. The maximum AQI recorded was 97 (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 Forrest County, Mississippi · 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.