Median AQI
40
Good
Arkansas · County air quality · 2025
Polk County, Arkansas
Median AQI 40 (Good). 81.2% of monitored days rated Good, direct from EPA Air Quality System stations.
- 40
- Median AQI
- 81.2%
- Good-air days
- 0
- Unhealthy days
- 56%
- Cleaner than US counties
The verdict
According to EPA Air Quality System monitoring data, Polk County's air is good on balance, cleaner than the median US county, a median AQI of 40 with 81.2% of 271 monitored days in the Good band, driven mainly by Ozone.
- 40
- median AQI · Good
- 81.2%
- days rated Good
- Ozone
- main pollutant
- 56%
- cleaner than US counties
Not one day crossed into the Unhealthy tier; the worst single reading was AQI 119.
Data updated July 2026
- Good · 220 d · 81.2%
- Moderate · 50 d · 18.5%
- USG · 1 d · 0.4%
How did Polk County's air break down in 2025?
Across 271 monitored days, 220 fell in the Good band (AQI 0–50) and 0 reached Unhealthy or worse. The worst single day peaked at AQI 119 (USG).
EPA AQS →Air quality data from EPA Air Quality System (2025). 271 days monitored. Median AQI: 40 (Good).
Insights: Polk County, Arkansas. EPA monitors recorded a median Air Quality Index of 40 across 271 measured days in 2025, earning a Good classification and a Good health grade. Of those days, 220 (81%) fell in the Good band (AQI 0–50), 50 (18%) registered Moderate readings, and 1 (0%) reached Unhealthy for Sensitive Groups. The 90th-percentile AQI settled at 58, while the worst single-day peak hit 119 (USG). Residents averaged about 24.4 clean-air days per 30-day window during the monitoring year.
The full pollutant mix ranks as Ozone (213 days), PM2.5 (58 days). Across the 2020–2025 trend window, good days shifted by -102 and the median AQI moved +3 points, placing the multi-year trajectory at worsening. The worst single reading over the 2020–2025 window was AQI 119, usg but never Unhealthy. Nearby counties show comparable readings: Arkansas (51.6% good, AQI 49); Ashley (53.9% good, AQI 49); Clark (97.5% good, AQI 35); Crittenden (79.8% good, AQI 41); Garland (52.8% good, AQI 49); Jackson (65.9% good, AQI 44).
Air Quality Summary
Good Days
81.2%
220 of 271 monitored days
6.2pp vs 75% target
Max AQI Recorded
119
USG
Health Grade
Good
90th-pct AQI 58
Polk County, Good days share 81.2%
National avg
Share of monitored days at AQI 0-50 (Good band).
Polk 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 271 monitored days across EPA AQI categories.
Good
220
81%
Moderate
50
18%
USG
1
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 Polk County.
- Ozone · 213 days · 78.6%
- PM2.5 · 58 days · 21.4%
Health Impact Assessment
Good
Polk County's air quality is rated Good based on 81.2% good air days. No unhealthy air days were recorded in 2025.
Air quality was acceptable on 81.2% of monitored days in 2025, with a median AQI of 40. Unusually sensitive people can check real-time conditions at AirNow.gov during high-pollution events.
The dominant pollutant is Ozone, driving AQI on 213 of 271 monitored days.
5-Year Air Quality Trend
Air quality is worsening in Polk County. Best year: 2020 (322 good days).
| Year | Good | Moderate | USG | Unhealthy | Median AQI | Max AQI |
|---|---|---|---|---|---|---|
| 2020 | 322 | 37 | 0 | 0 | 37 | 84 |
| 2021 | 299 | 61 | 0 | 0 | 40 | 93 |
| 2022 | 308 | 40 | 2 | 0 | 34 | 105 |
| 2023 | 188 | 54 | 0 | 0 | 40 | 92 |
| 2024 | 261 | 62 | 0 | 1 | 38 | 167 |
| 2025 | 220 | 50 | 1 | 0 | 40 | 119 |
How does Polk County compare?
How Polk County compares
Good-day share better than US avg
Polk County 81.2%
Arkansas County, Arkansas 51.6%
US average 76.5%
Median AQI worse than US avg
Polk County 40
Arkansas County, Arkansas 49
US average 38
Unhealthy days / yr about average
Polk County 0
Arkansas County, Arkansas 0
US average 0
Other Counties in Arkansas
Air quality comparison for nearby counties in Arkansas.
Counties with Similar Air Quality
Counties across the US with a similar median AQI to Polk County.
Amador County, California
AQI 40 · 84.8% good
Anne Arundel County, Maryland
AQI 40 · 87.2% good
Arlington County, Virginia
AQI 40 · 84.8% good
Bergen County, New Jersey
AQI 40 · 71.1% good
Berkeley County, West Virginia
AQI 40 · 81.1% good
Billings County, North Dakota
AQI 40 · 80.3% good
What Polk 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 40 means for exposure. Health guidance
- See how Polk County ranks against every monitored U.S. county on Good-day share. County rankings
- Compare Polk County with its Arkansas neighbours before drawing a conclusion about the region. All of Arkansas
Based on 271 EPA-monitored days in 2025; figures reflect only days the monitors reported. Source: EPA Air Quality System annual summaries.
More Air Quality Data
Air Quality Guides
Frequently Asked Questions
What is the air quality in Polk County, Arkansas? ▼
Polk County has a median Air Quality Index (AQI) of 40, rated "Good." 81.2% of monitored days (220 out of 271) had good air quality in 2025.
What is the main pollutant in Polk County? ▼
The primary pollutant in Polk County is Ozone (O3), which was the main AQI driver on 213 days (79% of monitored days). Can trigger asthma, reduce lung function, and cause chest pain.
How many unhealthy air days does Polk County have? ▼
In 2025, Polk County recorded 0 unhealthy air days (0 Unhealthy, 0 Very Unhealthy, 0 Hazardous). The maximum AQI reached 119.
Is the air quality in Polk County getting better or worse? ▼
Air quality in Polk County is worsening based on 5-year trends (2020-2025). Best year: 2020 with 322 good days. Worst year: 2023 with 188 good days.
What does AQI 40 mean for health? ▼
Polk County's median AQI of 40 falls in the "Good" category. See the <a href="/guides/understanding-aqi" class="underline">AQI category guide</a> for what each range means for health.
How does Polk County compare to other counties in Arkansas? ▼
Polk County has 81.2% good air days. Nearby counties in Arkansas: Arkansas (51.6% good), Ashley (53.9% good), Clark (97.5% good), Crittenden (79.8% good), Garland (52.8% good), Jackson (65.9% good).
What is the 90th percentile AQI in Polk County? ▼
The 90th percentile AQI for Polk County is 58, meaning 90% of monitored days had an AQI at or below this level. The maximum AQI recorded was 119 (USG).
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.
Every figure on PlainAir 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.